Programs & Examples On #Synchronized block

Can You Get A Users Local LAN IP Address Via JavaScript?

I cleaned up mido's post and then cleaned up the function that they found. This will either return false or an array. When testing remember that you need to collapse the array in the web developer console otherwise it's nonintuitive default behavior may deceive you in to thinking that it is returning an empty array.

function ip_local()
{
 var ip = false;
 window.RTCPeerConnection = window.RTCPeerConnection || window.mozRTCPeerConnection || window.webkitRTCPeerConnection || false;

 if (window.RTCPeerConnection)
 {
  ip = [];
  var pc = new RTCPeerConnection({iceServers:[]}), noop = function(){};
  pc.createDataChannel('');
  pc.createOffer(pc.setLocalDescription.bind(pc), noop);

  pc.onicecandidate = function(event)
  {
   if (event && event.candidate && event.candidate.candidate)
   {
    var s = event.candidate.candidate.split('\n');
    ip.push(s[0].split(' ')[4]);
   }
  }
 }

 return ip;
}

Additionally please keep in mind folks that this isn't something old-new like CSS border-radius though one of those bits that is outright not supported by IE11 and older. Always use object detection, test in reasonably older browsers (e.g. Firefox 4, IE9, Opera 12.1) and make sure your newer scripts aren't breaking your newer bits of code. Additionally always detect standards compliant code first so if there is something with say a CSS prefix detect the standard non-prefixed code first and then fall back as in the long term support will eventually be standardized for the rest of it's existence.

How to show current user name in a cell?

if you don't want to create a UDF in VBA or you can't, this could be an alternative.

=Cell("Filename",A1) this will give you the full file name, and from this you could get the user name with something like this:

=Mid(A1,Find("\",A1,4)+1;Find("\";A1;Find("\";A1;4))-2)


This Formula runs only from a workbook saved earlier.

You must start from 4th position because of the first slash from the drive.

Get the height and width of the browser viewport without scrollbars using jquery?

The script $(window).height() does work well (showing the viewport's height and not the document with scrolling height), BUT it needs that you put correctly the doctype tag in your document, for example these doctypes:

For html5: <!doctype html>

for transitional html4: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

Probably the default doctype assumed by some browsers is such, that $(window).height() takes the document's height and not the browser's height. With the doctype specification, it's satisfactorily solved, and I'm pretty sure you peps will avoid the "changing scroll-overflow to hidden and then back", which is, I'm sorry, a bit dirty trick, specially if you don't document it on the code for future programmer's usage.

Moreover, if you are doing a script, you can invent tests to help programmers in your libraries, let me invent a couple:

$(document).ready(function() {
    if(typeof $=='undefined') {
        alert("Error, you haven't called JQuery library");
    }
    if(document.doctype==null || screen.height < parseInt($(window).height()) ) {
        alert("ERROR, check your doctype, the calculated heights are not what you might expect");
    } 
});

Get checkbox values using checkbox name using jquery

You are selecting inputs with name attribute of "bla", but your inputs have "bla[]" name attribute.

$("input[name='bla[]']").each(function (index, obj) {
        // loop all checked items
    });

http://jsfiddle.net/26axX/

How to add a new project to Github using VS Code

Here are the detailed steps needed to achieve this.

The existing commands can be simply run via the CLI terminal of VS-CODE. It is understood that Git is installed in the system, configured with desired username and email Id.

1) Navigate to the local project directory and create a local git repository:

 git init

2) Once that is successful, click on the 'Source Control' icon on the left navbar in VS-Code.One should be able to see files ready to be commit-ed. Press on 'Commit' button, provide comments, stage the changes and commit the files. Alternatively you can run from CLI

git commit -m "Your comment"

3) Now you need to visit your GitHub account and create a new Repository. Exclude creating 'README.md', '.gitIgnore' files. Also do not add any License to the repo. Sometimes these settings cause issue while pushing in.

4) Copy the link to this newly created GitHub Repository.

5) Come back to the terminal in VS-CODE and type these commands in succession:

git remote add origin <Link to GitHub Repo>     //maps the remote repo link to local git repo

git remote -v                                  //this is to verify the link to the remote repo 

git push -u origin master                      // pushes the commit-ed changes into the remote repo

Note: If it is the first time the local git account is trying to connect to GitHub, you may be required to enter credentials to GitHub in a separate window.

6) You can see the success message in the Terminal. You can also verify by refreshing the GitHub repo online.

Hope this helps

The CodeDom provider type "Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider" could not be located

Regarding this error I've tried:

  • Cleaning and rebuilding the project
  • Unloading and reloading the project
  • Modifying the Target Framework
  • Modifying the Output path
  • Adding nuggets to the GAC
  • Deleting the packages uninstall-package Microsoft.CodeDom.Providers.DotNetCompilerPlatform uninstall-package Microsoft.Net.Compilers and installing them again.

While these all seem to be valid solutions, I was only able to generate new errors and in the end, the error seems able to display when certain references/nugets are missing.

In my case, I had recently reinstalled Microsoft Office and was referencing assemblies like Microsoft.Office.Core. The new install didn't seem to include the required packages, which made it so my solution couldn't build correctly.

I was able to solve this issue by reworking my code to the point where I didn't need to reference Microsoft.Office, but could've solved it by looking up the required packages and installing them accordingly.

Seems like an unclear error message from Visual Studio.

Check if string is neither empty nor space in shell script

To check if a string is empty or contains only whitespace you could use:

shopt -s extglob  # more powerful pattern matching

if [ -n "${str##+([[:space:]])}" ]; then
    echo '$str is not null or space'
fi

See Shell Parameter Expansion and Pattern Matching in the Bash Manual.

J2ME/Android/BlackBerry - driving directions, route between two locations

J2ME Map Route Provider

maps.google.com has a navigation service which can provide you route information in KML format.

To get kml file we need to form url with start and destination locations:

public static String getUrl(double fromLat, double fromLon,
                            double toLat, double toLon) {// connect to map web service
    StringBuffer urlString = new StringBuffer();
    urlString.append("http://maps.google.com/maps?f=d&hl=en");
    urlString.append("&saddr=");// from
    urlString.append(Double.toString(fromLat));
    urlString.append(",");
    urlString.append(Double.toString(fromLon));
    urlString.append("&daddr=");// to
    urlString.append(Double.toString(toLat));
    urlString.append(",");
    urlString.append(Double.toString(toLon));
    urlString.append("&ie=UTF8&0&om=0&output=kml");
    return urlString.toString();
}

Next you will need to parse xml (implemented with SAXParser) and fill data structures:

public class Point {
    String mName;
    String mDescription;
    String mIconUrl;
    double mLatitude;
    double mLongitude;
}

public class Road {
    public String mName;
    public String mDescription;
    public int mColor;
    public int mWidth;
    public double[][] mRoute = new double[][] {};
    public Point[] mPoints = new Point[] {};
}

Network connection is implemented in different ways on Android and Blackberry, so you will have to first form url:

 public static String getUrl(double fromLat, double fromLon,
     double toLat, double toLon)

then create connection with this url and get InputStream.
Then pass this InputStream and get parsed data structure:

 public static Road getRoute(InputStream is) 

Full source code RoadProvider.java

BlackBerry

class MapPathScreen extends MainScreen {
    MapControl map;
    Road mRoad = new Road();
    public MapPathScreen() {
        double fromLat = 49.85, fromLon = 24.016667;
        double toLat = 50.45, toLon = 30.523333;
        String url = RoadProvider.getUrl(fromLat, fromLon, toLat, toLon);
        InputStream is = getConnection(url);
        mRoad = RoadProvider.getRoute(is);
        map = new MapControl();
        add(new LabelField(mRoad.mName));
        add(new LabelField(mRoad.mDescription));
        add(map);
    }
    protected void onUiEngineAttached(boolean attached) {
        super.onUiEngineAttached(attached);
        if (attached) {
            map.drawPath(mRoad);
        }
    }
    private InputStream getConnection(String url) {
        HttpConnection urlConnection = null;
        InputStream is = null;
        try {
            urlConnection = (HttpConnection) Connector.open(url);
            urlConnection.setRequestMethod("GET");
            is = urlConnection.openInputStream();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return is;
    }
}

See full code on J2MEMapRouteBlackBerryEx on Google Code

Android

Android G1 screenshot

public class MapRouteActivity extends MapActivity {
    LinearLayout linearLayout;
    MapView mapView;
    private Road mRoad;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mapView = (MapView) findViewById(R.id.mapview);
        mapView.setBuiltInZoomControls(true);
        new Thread() {
            @Override
            public void run() {
                double fromLat = 49.85, fromLon = 24.016667;
                double toLat = 50.45, toLon = 30.523333;
                String url = RoadProvider
                        .getUrl(fromLat, fromLon, toLat, toLon);
                InputStream is = getConnection(url);
                mRoad = RoadProvider.getRoute(is);
                mHandler.sendEmptyMessage(0);
            }
        }.start();
    }

    Handler mHandler = new Handler() {
        public void handleMessage(android.os.Message msg) {
            TextView textView = (TextView) findViewById(R.id.description);
            textView.setText(mRoad.mName + " " + mRoad.mDescription);
            MapOverlay mapOverlay = new MapOverlay(mRoad, mapView);
            List<Overlay> listOfOverlays = mapView.getOverlays();
            listOfOverlays.clear();
            listOfOverlays.add(mapOverlay);
            mapView.invalidate();
        };
    };

    private InputStream getConnection(String url) {
        InputStream is = null;
        try {
            URLConnection conn = new URL(url).openConnection();
            is = conn.getInputStream();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return is;
    }
    @Override
    protected boolean isRouteDisplayed() {
        return false;
    }
}

See full code on J2MEMapRouteAndroidEx on Google Code

How to parse freeform street/postal address out of text, and into components

No code? For shame!

Here is a simple JavaScript address parser. It's pretty awful for every single reason that Matt gives in his dissertation above (which I almost 100% agree with: addresses are complex types, and humans make mistakes; better to outsource and automate this - when you can afford to).

But rather than cry, I decided to try:

This code works OK for parsing most Esri results for findAddressCandidate and also with some other (reverse)geocoders that return single-line address where street/city/state are delimited by commas. You can extend if you want or write country-specific parsers. Or just use this as case study of how challenging this exercise can be or at how lousy I am at JavaScript. I admit I only spent about thirty mins on this (future iterations could add caches, zip validation, and state lookups as well as user location context), but it worked for my use case: End user sees form that parses geocode search response into 4 textboxes. If address parsing comes out wrong (which is rare unless source data was poor) it's no big deal - the user gets to verify and fix it! (But for automated solutions could either discard/ignore or flag as error so dev can either support the new format or fix source data.)

_x000D_
_x000D_
/* _x000D_
address assumptions:_x000D_
- US addresses only (probably want separate parser for different countries)_x000D_
- No country code expected._x000D_
- if last token is a number it is probably a postal code_x000D_
-- 5 digit number means more likely_x000D_
- if last token is a hyphenated string it might be a postal code_x000D_
-- if both sides are numeric, and in form #####-#### it is more likely_x000D_
- if city is supplied, state will also be supplied (city names not unique)_x000D_
- zip/postal code may be omitted even if has city & state_x000D_
- state may be two-char code or may be full state name._x000D_
- commas: _x000D_
-- last comma is usually city/state separator_x000D_
-- second-to-last comma is possibly street/city separator_x000D_
-- other commas are building-specific stuff that I don't care about right now._x000D_
- token count:_x000D_
-- because units, street names, and city names may contain spaces token count highly variable._x000D_
-- simplest address has at least two tokens: 714 OAK_x000D_
-- common simple address has at least four tokens: 714 S OAK ST_x000D_
-- common full (mailing) address has at least 5-7:_x000D_
--- 714 OAK, RUMTOWN, VA 59201_x000D_
--- 714 S OAK ST, RUMTOWN, VA 59201_x000D_
-- complex address may have a dozen or more:_x000D_
--- MAGICICIAN SUPPLY, LLC, UNIT 213A, MAGIC TOWN MALL, 13 MAGIC CIRCLE DRIVE, LAND OF MAGIC, MA 73122-3412_x000D_
*/_x000D_
_x000D_
var rawtext = $("textarea").val();_x000D_
var rawlist = rawtext.split("\n");_x000D_
_x000D_
function ParseAddressEsri(singleLineaddressString) {_x000D_
  var address = {_x000D_
    street: "",_x000D_
    city: "",_x000D_
    state: "",_x000D_
    postalCode: ""_x000D_
  };_x000D_
_x000D_
  // tokenize by space (retain commas in tokens)_x000D_
  var tokens = singleLineaddressString.split(/[\s]+/);_x000D_
  var tokenCount = tokens.length;_x000D_
  var lastToken = tokens.pop();_x000D_
  if (_x000D_
    // if numeric assume postal code (ignore length, for now)_x000D_
    !isNaN(lastToken) ||_x000D_
    // if hyphenated assume long zip code, ignore whether numeric, for now_x000D_
    lastToken.split("-").length - 1 === 1) {_x000D_
    address.postalCode = lastToken;_x000D_
    lastToken = tokens.pop();_x000D_
  }_x000D_
_x000D_
  if (lastToken && isNaN(lastToken)) {_x000D_
    if (address.postalCode.length && lastToken.length === 2) {_x000D_
      // assume state/province code ONLY if had postal code_x000D_
      // otherwise it could be a simple address like "714 S OAK ST"_x000D_
      // where "ST" for "street" looks like two-letter state code_x000D_
      // possibly this could be resolved with registry of known state codes, but meh. (and may collide anyway)_x000D_
      address.state = lastToken;_x000D_
      lastToken = tokens.pop();_x000D_
    }_x000D_
    if (address.state.length === 0) {_x000D_
      // check for special case: might have State name instead of State Code._x000D_
      var stateNameParts = [lastToken.endsWith(",") ? lastToken.substring(0, lastToken.length - 1) : lastToken];_x000D_
_x000D_
      // check remaining tokens from right-to-left for the first comma_x000D_
      while (2 + 2 != 5) {_x000D_
        lastToken = tokens.pop();_x000D_
        if (!lastToken) break;_x000D_
        else if (lastToken.endsWith(",")) {_x000D_
          // found separator, ignore stuff on left side_x000D_
          tokens.push(lastToken); // put it back_x000D_
          break;_x000D_
        } else {_x000D_
          stateNameParts.unshift(lastToken);_x000D_
        }_x000D_
      }_x000D_
      address.state = stateNameParts.join(' ');_x000D_
      lastToken = tokens.pop();_x000D_
    }_x000D_
  }_x000D_
_x000D_
  if (lastToken) {_x000D_
    // here is where it gets trickier:_x000D_
    if (address.state.length) {_x000D_
      // if there is a state, then assume there is also a city and street._x000D_
      // PROBLEM: city may be multiple words (spaces)_x000D_
      // but we can pretty safely assume next-from-last token is at least PART of the city name_x000D_
      // most cities are single-name. It would be very helpful if we knew more context, like_x000D_
      // the name of the city user is in. But ignore that for now._x000D_
      // ideally would have zip code service or lookup to give city name for the zip code._x000D_
      var cityNameParts = [lastToken.endsWith(",") ? lastToken.substring(0, lastToken.length - 1) : lastToken];_x000D_
_x000D_
      // assumption / RULE: street and city must have comma delimiter_x000D_
      // addresses that do not follow this rule will be wrong only if city has space_x000D_
      // but don't care because Esri formats put comma before City_x000D_
      var streetNameParts = [];_x000D_
_x000D_
      // check remaining tokens from right-to-left for the first comma_x000D_
      while (2 + 2 != 5) {_x000D_
        lastToken = tokens.pop();_x000D_
        if (!lastToken) break;_x000D_
        else if (lastToken.endsWith(",")) {_x000D_
          // found end of street address (may include building, etc. - don't care right now)_x000D_
          // add token back to end, but remove trailing comma (it did its job)_x000D_
          tokens.push(lastToken.endsWith(",") ? lastToken.substring(0, lastToken.length - 1) : lastToken);_x000D_
          streetNameParts = tokens;_x000D_
          break;_x000D_
        } else {_x000D_
          cityNameParts.unshift(lastToken);_x000D_
        }_x000D_
      }_x000D_
      address.city = cityNameParts.join(' ');_x000D_
      address.street = streetNameParts.join(' ');_x000D_
    } else {_x000D_
      // if there is NO state, then assume there is NO city also, just street! (easy)_x000D_
      // reasoning: city names are not very original (Portland, OR and Portland, ME) so if user wants city they need to store state also (but if you are only ever in Portlan, OR, you don't care about city/state)_x000D_
      // put last token back in list, then rejoin on space_x000D_
      tokens.push(lastToken);_x000D_
      address.street = tokens.join(' ');_x000D_
    }_x000D_
  }_x000D_
  // when parsing right-to-left hard to know if street only vs street + city/state_x000D_
  // hack fix for now is to shift stuff around._x000D_
  // assumption/requirement: will always have at least street part; you will never just get "city, state"  _x000D_
  // could possibly tweak this with options or more intelligent parsing&sniffing_x000D_
  if (!address.city && address.state) {_x000D_
    address.city = address.state;_x000D_
    address.state = '';_x000D_
  }_x000D_
  if (!address.street) {_x000D_
    address.street = address.city;_x000D_
    address.city = '';_x000D_
  }_x000D_
_x000D_
  return address;_x000D_
}_x000D_
_x000D_
// get list of objects with discrete address properties_x000D_
var addresses = rawlist_x000D_
  .filter(function(o) {_x000D_
    return o.length > 0_x000D_
  })_x000D_
  .map(ParseAddressEsri);_x000D_
$("#output").text(JSON.stringify(addresses));_x000D_
console.log(addresses);
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<textarea>_x000D_
27488 Stanford Ave, Bowden, North Dakota_x000D_
380 New York St, Redlands, CA 92373_x000D_
13212 E SPRAGUE AVE, FAIR VALLEY, MD 99201_x000D_
1005 N Gravenstein Highway, Sebastopol CA 95472_x000D_
A. P. Croll &amp; Son 2299 Lewes-Georgetown Hwy, Georgetown, DE 19947_x000D_
11522 Shawnee Road, Greenwood, DE 19950_x000D_
144 Kings Highway, S.W. Dover, DE 19901_x000D_
Intergrated Const. Services 2 Penns Way Suite 405, New Castle, DE 19720_x000D_
Humes Realty 33 Bridle Ridge Court, Lewes, DE 19958_x000D_
Nichols Excavation 2742 Pulaski Hwy, Newark, DE 19711_x000D_
2284 Bryn Zion Road, Smyrna, DE 19904_x000D_
VEI Dover Crossroads, LLC 1500 Serpentine Road, Suite 100 Baltimore MD 21_x000D_
580 North Dupont Highway, Dover, DE 19901_x000D_
P.O. Box 778, Dover, DE 19903_x000D_
714 S OAK ST_x000D_
714 S OAK ST, RUM TOWN, VA, 99201_x000D_
3142 E SPRAGUE AVE, WHISKEY VALLEY, WA 99281_x000D_
27488 Stanford Ave, Bowden, North Dakota_x000D_
380 New York St, Redlands, CA 92373_x000D_
</textarea>_x000D_
<div id="output">_x000D_
</div>
_x000D_
_x000D_
_x000D_

Best way to implement multi-language/globalization in large .NET project

You can use commercial tools like Sisulizer. It will create satellite assembly for each language. Only thing you should pay attention is not to obfuscate form class names (if you use obfuscator).

How to sort a data frame by date

The only way I found to work with hours, through an US format in source (mm-dd-yyyy HH-MM-SS PM/AM)...

df_dataSet$time <- as.POSIXct( df_dataSet$time , format = "%m/%d/%Y %I:%M:%S %p" , tz = "GMT")
class(df_dataSet$time)
df_dataSet <- df_dataSet[do.call(order, df_dataSet), ] 

How to parse a CSV file using PHP

A bit shorter answer since PHP >= 5.3.0:

    $csvFile = file('../somefile.csv');
    $data = [];
    foreach ($csvFile as $line) {
        $data[] = str_getcsv($line);
    }

Spring Boot: Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean

I've had similar problems when the main method is on a different class than that passed to SpringApplcation.run()

So the solution would be to use the line you've commented out:

public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

How to convert a string of numbers to an array of numbers?

Map it to integers:

a.split(',').map(function(i){
    return parseInt(i, 10);
})

map looks at every array item, passes it to the function provided and returns an array with the return values of that function. map isn't available in old browsers, but most libraries like jQuery or underscore include a cross-browser version.

Or, if you prefer loops:

var res = a.split(",");
for (var i=0; i<res.length; i++)
{
    res[i] = parseInt(res[i], 10);
}

Is there a math nCr function in python?

The following program calculates nCr in an efficient manner (compared to calculating factorials etc.)

import operator as op
from functools import reduce

def ncr(n, r):
    r = min(r, n-r)
    numer = reduce(op.mul, range(n, n-r, -1), 1)
    denom = reduce(op.mul, range(1, r+1), 1)
    return numer // denom  # or / in Python 2

As of Python 3.8, binomial coefficients are available in the standard library as math.comb:

>>> from math import comb
>>> comb(10,3)
120

Remove Backslashes from Json Data in JavaScript

tl;dr: You don't have to remove the slashes, you have nested JSON, and hence have to decode the JSON twice: DEMO (note I used double slashes in the example, because the JSON is inside a JS string literal).


I assume that your actual JSON looks like

{"data":"{\n \"taskNames\" : [\n \"01 Jan\",\n \"02 Jan\",\n \"03 Jan\",\n \"04 Jan\",\n \"05 Jan\",\n \"06 Jan\",\n \"07 Jan\",\n \"08 Jan\",\n \"09 Jan\",\n \"10 Jan\",\n \"11 Jan\",\n \"12 Jan\",\n \"13 Jan\",\n \"14 Jan\",\n \"15 Jan\",\n \"16 Jan\",\n \"17 Jan\",\n \"18 Jan\",\n \"19 Jan\",\n \"20 Jan\",\n \"21 Jan\",\n \"22 Jan\",\n \"23 Jan\",\n \"24 Jan\",\n \"25 Jan\",\n \"26 Jan\",\n \"27 Jan\"]}"}

I.e. you have a top level object with one key, data. The value of that key is a string containing JSON itself. This is usually because the server side code didn't properly create the JSON. That's why you see the \" inside the string. This lets the parser know that " is to be treated literally and doesn't terminate the string.

So you can either fix the server side code, so that you don't double encode the data, or you have to decode the JSON twice, e.g.

var data = JSON.parse(JSON.parse(json).data));

Update values from one column in same table to another in SQL Server

UPDATE a
SET a.column1 = b.column2
FROM myTable a 
INNER JOIN myTable b
on a.myID = b.myID

in order for both "a" and "b" to work, both aliases must be defined

width:auto for <input> fields

Because input's width is controlled by it's size attribute, this is how I initialize an input width according to its content:

<input type="text" class="form-list-item-name" [size]="myInput.value.length" #myInput>

Replace all double quotes within String

Here's how

String details = "Hello \"world\"!";
details = details.replace("\"","\\\"");
System.out.println(details);               // Hello \"world\"!

Note that strings are immutable, thus it is not sufficient to simply do details.replace("\"","\\\""). You must reassign the variable details to the resulting string.


Using

details = details.replaceAll("\"","&quote;");

instead, results in

Hello &quote;world&quote;!

Redis strings vs Redis hashes to represent JSON: efficiency?

This article can provide a lot of insight here: http://redis.io/topics/memory-optimization

There are many ways to store an array of Objects in Redis (spoiler: I like option 1 for most use cases):

  1. Store the entire object as JSON-encoded string in a single key and keep track of all Objects using a set (or list, if more appropriate). For example:

    INCR id:users
    SET user:{id} '{"name":"Fred","age":25}'
    SADD users {id}
    

    Generally speaking, this is probably the best method in most cases. If there are a lot of fields in the Object, your Objects are not nested with other Objects, and you tend to only access a small subset of fields at a time, it might be better to go with option 2.

    Advantages: considered a "good practice." Each Object is a full-blown Redis key. JSON parsing is fast, especially when you need to access many fields for this Object at once. Disadvantages: slower when you only need to access a single field.

  2. Store each Object's properties in a Redis hash.

    INCR id:users
    HMSET user:{id} name "Fred" age 25
    SADD users {id}
    

    Advantages: considered a "good practice." Each Object is a full-blown Redis key. No need to parse JSON strings. Disadvantages: possibly slower when you need to access all/most of the fields in an Object. Also, nested Objects (Objects within Objects) cannot be easily stored.

  3. Store each Object as a JSON string in a Redis hash.

    INCR id:users
    HMSET users {id} '{"name":"Fred","age":25}'
    

    This allows you to consolidate a bit and only use two keys instead of lots of keys. The obvious disadvantage is that you can't set the TTL (and other stuff) on each user Object, since it is merely a field in the Redis hash and not a full-blown Redis key.

    Advantages: JSON parsing is fast, especially when you need to access many fields for this Object at once. Less "polluting" of the main key namespace. Disadvantages: About same memory usage as #1 when you have a lot of Objects. Slower than #2 when you only need to access a single field. Probably not considered a "good practice."

  4. Store each property of each Object in a dedicated key.

    INCR id:users
    SET user:{id}:name "Fred"
    SET user:{id}:age 25
    SADD users {id}
    

    According to the article above, this option is almost never preferred (unless the property of the Object needs to have specific TTL or something).

    Advantages: Object properties are full-blown Redis keys, which might not be overkill for your app. Disadvantages: slow, uses more memory, and not considered "best practice." Lots of polluting of the main key namespace.

Overall Summary

Option 4 is generally not preferred. Options 1 and 2 are very similar, and they are both pretty common. I prefer option 1 (generally speaking) because it allows you to store more complicated Objects (with multiple layers of nesting, etc.) Option 3 is used when you really care about not polluting the main key namespace (i.e. you don't want there to be a lot of keys in your database and you don't care about things like TTL, key sharding, or whatever).

If I got something wrong here, please consider leaving a comment and allowing me to revise the answer before downvoting. Thanks! :)

Compile a DLL in C/C++, then call it from another program

The thing to watch out for when writing C++ dlls is name mangling. If you want interoperability between C and C++, you'd be better off by exporting non-mangled C-style functions from within the dll.

You have two options to use a dll

  • Either use a lib file to link the symbols -- compile time dynamic linking
  • Use LoadLibrary() or some suitable function to load the library, retrieve a function pointer (GetProcAddress) and call it -- runtime dynamic linking

Exporting classes will not work if you follow the second method though.

Angular.js directive dynamic templateURL

You can use ng-include directive.

Try something like this:

emanuel.directive('hymn', function() {
   return {
       restrict: 'E',
       link: function(scope, element, attrs) {
           scope.getContentUrl = function() {
                return 'content/excerpts/hymn-' + attrs.ver + '.html';
           }
       },
       template: '<div ng-include="getContentUrl()"></div>'
   }
});

UPD. for watching ver attribute

emanuel.directive('hymn', function() {
   return {
       restrict: 'E',
       link: function(scope, element, attrs) {
           scope.contentUrl = 'content/excerpts/hymn-' + attrs.ver + '.html';
           attrs.$observe("ver",function(v){
               scope.contentUrl = 'content/excerpts/hymn-' + v + '.html';
           });
       },
       template: '<div ng-include="contentUrl"></div>'
   }
});

how to wait for first command to finish?

Shell scripts, no matter how they are executed, execute one command after the other. So your code will execute results.sh after the last command of st_new.sh has finished.

Now there is a special command which messes this up: &

cmd &

means: "Start a new background process and execute cmd in it. After starting the background process, immediately continue with the next command in the script."

That means & doesn't wait for cmd to do it's work. My guess is that st_new.sh contains such a command. If that is the case, then you need to modify the script:

cmd &
BACK_PID=$!

This puts the process ID (PID) of the new background process in the variable BACK_PID. You can then wait for it to end:

while kill -0 $BACK_PID ; do
    echo "Process is still active..."
    sleep 1
    # You can add a timeout here if you want
done

or, if you don't want any special handling/output simply

wait $BACK_PID

Note that some programs automatically start a background process when you run them, even if you omit the &. Check the documentation, they often have an option to write their PID to a file or you can run them in the foreground with an option and then use the shell's & command instead to get the PID.

Tracking changes in Windows registry

Regarding WMI and Registry:

There are three WMI event classes concerning registry:

  • RegistryTreeChangeEvent
  • RegistryKeyChangeEvent
  • RegistryValueChangeEvent

Registry Event Classes

But you need to be aware of these limitations:

  • With RegistryTreeChangeEvent and RegistryKeyChangeEvent there is no way of directly telling which values or keys actually changed. To do this, you would need to save the registry state before the event and compare it to the state after the event.

  • You can't use these classes with HKEY_CLASSES_ROOT or HKEY_CURRENT_USER hives. You can overcome this by creating a WMI class to represent the registry key to monitor:

Defining a Registry Class With Qualifiers

and use it with __InstanceOperationEvent derived classes.

So using WMI to monitor the Registry is possible, but less then perfect. The advantage is that it is possible to monitor the changes in 'real time'. Another advantage could be WMI permanent event subscription:

Receiving Events at All Times

a method to monitor the Registry 'at all times', ie. event if your application is not running.

Generating statistics from Git repository

commits per author

git shortlog -s -n 

Define an <img>'s src attribute in CSS

After trying these solutions I still wasn't satisfied but I found a solution in this article and it works in Chrome, Firefox, Opera, Safari, IE8+

#divId {

  display: block;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  background: url(http://notrealdomain2.com/newbanner.png) no-repeat;
  width: 180px; /* Width of new image */
  height: 236px; /* Height of new image */
  padding-left: 180px; /* Equal to width of new image */

}

How to reference Microsoft.Office.Interop.Excel dll?

Building off of Mulfix's answer, if you have Visual Studio Community 2015, try Add Reference... -> COM -> Type Libraries -> 'Microsoft Excel 15.0 Object Library'.

PHP: Get the key from an array in a foreach loop

Use foreach with key and value.

Example:

foreach($samplearr as $key => $val) {
     print "<tr><td>" 
         . $key 
         . "</td><td>" 
         . $val['value1'] 
         . "</td><td>" 
         . $val['value2'] 
         . "</td></tr>";
}

CROSS JOIN vs INNER JOIN in SQL

Cross join does not combine the rows, if you have 100 rows in each table with 1 to 1 match, you get 10.000 results, Innerjoin will only return 100 rows in the same situation.

These 2 examples will return the same result:

Cross join

select * from table1 cross join table2 where table1.id = table2.fk_id

Inner join

select * from table1 join table2 on table1.id = table2.fk_id

Use the last method

jQuery to retrieve and set selected option value of html select element

$('#myId').val() should do it, failing that I would try:

$('#myId option:selected').val()

What's the difference between JavaScript and JScript?

There are some code differences to be aware of.

A negative first parameter to subtr is not supported, e.g. in Javascript: "string".substr(-1) returns "g", whereas in JScript: "string".substr(-1) returns "string"

It's possible to do "string"[0] to get "s" in Javascript, but JScript doesn't support such a construct. (Actually, only modern browsers appear to support the "string"[0] construct.

How to rename array keys in PHP?

Talking about functional PHP, I have this more generic answer:

    array_map(function($arr){
        $ret = $arr;
        $ret['value'] = $ret['url'];
        unset($ret['url']);
        return $ret;
    }, $tag);
}

div inside table

It is allow as TD can contain inline- AND block-elements.

Here you can find it in the reference: http://xhtml.com/en/xhtml/reference/td/#td-contains

What's the difference between process.cwd() vs __dirname?

$ find proj

proj
proj/src
proj/src/index.js

$ cat proj/src/index.js

console.log("process.cwd() = " + process.cwd());
console.log("__dirname = " + __dirname);

$ cd proj; node src/index.js

process.cwd() = /tmp/proj
__dirname = /tmp/proj/src

How do I handle Database Connections with Dapper in .NET?

Try this:

public class ConnectionProvider
    {
        DbConnection conn;
        string connectionString;
        DbProviderFactory factory;

        // Constructor that retrieves the connectionString from the config file
        public ConnectionProvider()
        {
            this.connectionString = ConfigurationManager.ConnectionStrings[0].ConnectionString.ToString();
            factory = DbProviderFactories.GetFactory(ConfigurationManager.ConnectionStrings[0].ProviderName.ToString());
        }

        // Constructor that accepts the connectionString and Database ProviderName i.e SQL or Oracle
        public ConnectionProvider(string connectionString, string connectionProviderName)
        {
            this.connectionString = connectionString;
            factory = DbProviderFactories.GetFactory(connectionProviderName);
        }

        // Only inherited classes can call this.
        public DbConnection GetOpenConnection()
        {
            conn = factory.CreateConnection();
            conn.ConnectionString = this.connectionString;
            conn.Open();

            return conn;
        }

    }

Calling Java from Python

I'm assuming that if you can get from C++ to Java then you are all set. I've seen a product of the kind you mention work well. As it happens the one we used was CodeMesh. I'm not specifically endorsing this vendor, or making any statement about their product's relative quality, but I have seen it work in quite a high volume scenario.

I would say generally that if at all possible I would recommend keeping away from direct integration via JNI if you can. Some simple REST service approach, or queue-based architecture will tend to be simpler to develop and diagnose. You can get quite decent perfomance if you use such decoupled technologies carefully.

Gradle finds wrong JAVA_HOME even though it's correctly set

I had the same problem, but I didnt find export command in line 70 in gradle file for the latest version 2.13, but I understand a silly mistake there, that is following,

If you don't find line 70 with export command in gradle file in your gradle folder/bin/ , then check your ~/.bashrc, if you find export JAVA_HOME==/usr/lib/jvm/java-7-openjdk-amd64/bin/java, then remove /bin/java from this line, like JAVA_HOME==/usr/lib/jvm/java-7-openjdk-amd64, and it in path>>> instead of this export PATH=$PATH:$HOME/bin:JAVA_HOME/, it will be export PATH=$PATH:$HOME/bin:JAVA_HOME/bin/java. Then run source ~/.bashrc.

The reason is, if you check your gradle file, you will find in line 70 (if there's no export command) or in line 75,

JAVACMD="$JAVA_HOME/bin/java"
    fi
    if [ ! -x "$JAVACMD" ] ; then
        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME

That means /bin/java is already there, so it needs to be substracted from JAVA_HOME path.

That happened in my case.

How to read a text file in project's root directory?

From Solution Explorer, right click on myfile.txt and choose "Properties"

From there, set the Build Action to content and Copy to Output Directory to either Copy always or Copy if newer

enter image description here

json_encode/json_decode - returns stdClass instead of Array in PHP

Take a closer look at the second parameter of json_decode($json, $assoc, $depth) at https://secure.php.net/json_decode

difference between primary key and unique key

A Primary key is a unique key.

Each table must have at most ONE primary key but it can have multiple unique key. A primary key is used to uniquely identify a table row. A primary key cannot be NULL since NULL is not a value.

How to get visitor's location (i.e. country) using geolocation?

You don't need to locate the user if you only need their country. You can look their IP address up in any IP-to-location service (like maxmind, ipregistry or ip2location). This will be accurate most of the time.

If you really need to get their location, you can get their lat/lng with that method, then query Google's or Yahoo's reverse geocoding service.

How to select rows in a DataFrame between two values, in Python Pandas?

there is a nicer alternative - use query() method:

In [58]: df = pd.DataFrame({'closing_price': np.random.randint(95, 105, 10)})

In [59]: df
Out[59]:
   closing_price
0            104
1             99
2             98
3             95
4            103
5            101
6            101
7             99
8             95
9             96

In [60]: df.query('99 <= closing_price <= 101')
Out[60]:
   closing_price
1             99
5            101
6            101
7             99

UPDATE: answering the comment:

I like the syntax here but fell down when trying to combine with expresison; df.query('(mean + 2 *sd) <= closing_price <=(mean + 2 *sd)')

In [161]: qry = "(closing_price.mean() - 2*closing_price.std())" +\
     ...:       " <= closing_price <= " + \
     ...:       "(closing_price.mean() + 2*closing_price.std())"
     ...:

In [162]: df.query(qry)
Out[162]:
   closing_price
0             97
1            101
2             97
3             95
4            100
5             99
6            100
7            101
8             99
9             95

Overcoming "Display forbidden by X-Frame-Options"

The only real answer, if you don't control the headers on your source you want in your iframe, is to proxy it. Have a server act as a client, receive the source, strip the problematic headers, add CORS if needed, and then ping your own server.

There is one other answer explaining how to write such a proxy. It isn't difficult, but I was sure someone had to have done this before. It was just difficult to find it, for some reason.

I finally did find some sources:

https://github.com/Rob--W/cors-anywhere/#documentation

^ preferred. If you need rare usage, I think you can just use his heroku app. Otherwise, it's code to run it yourself on your own server. Note sure what the limits are.

whateverorigin.org

^ second choice, but quite old. supposedly newer choice in python: https://github.com/Eiledon/alloworigin

then there's the third choice:

http://anyorigin.com/

Which seems to allow a little free usage, but will put you on a public shame list if you don't pay and use some unspecified amount, which you can only be removed from if you pay the fee...

How to set environment variable for everyone under my linux system?

Some interesting excerpts from the bash manpage:

When bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads and executes commands from the first one that exists and is readable. The --noprofile option may be used when the shell is started to inhibit this behavior.
...
When an interactive shell that is not a login shell is started, bash reads and executes commands from /etc/bash.bashrc and ~/.bashrc, if these files exist. This may be inhibited by using the --norc option. The --rcfile file option will force bash to read and execute commands from file instead of /etc/bash.bashrc and ~/.bashrc.

So have a look at /etc/profile or /etc/bash.bashrc, these files are the right places for global settings. Put something like this in them to set up an environement variable:

export MY_VAR=xxx

Confusing error in R: Error in scan(file, what, nmax, sep, dec, quote, skip, nlines, na.strings, : line 1 did not have 42 elements)

To read characters try

scan("/PathTo/file.csv", "")

If you're reading numeric values, then just use

scan("/PathTo/file.csv")

scan by default will use white space as separator. The type of the second arg defines 'what' to read (defaults to double()).

How to find out the number of CPUs using python

Another option is to use the psutil library, which always turn out useful in these situations:

>>> import psutil
>>> psutil.cpu_count()
2

This should work on any platform supported by psutil(Unix and Windows).

Note that in some occasions multiprocessing.cpu_count may raise a NotImplementedError while psutil will be able to obtain the number of CPUs. This is simply because psutil first tries to use the same techniques used by multiprocessing and, if those fail, it also uses other techniques.

How to exclude records with certain values in sql select

One way:

SELECT DISTINCT sc.StoreId
FROM StoreClients sc
WHERE NOT EXISTS(
    SELECT * FROM StoreClients sc2 
    WHERE sc2.StoreId = sc.StoreId AND sc2.ClientId = 5)

How does String substring work in Swift

Swift 4 & 5:

extension String {
  subscript(_ i: Int) -> String {
    let idx1 = index(startIndex, offsetBy: i)
    let idx2 = index(idx1, offsetBy: 1)
    return String(self[idx1..<idx2])
  }

  subscript (r: Range<Int>) -> String {
    let start = index(startIndex, offsetBy: r.lowerBound)
    let end = index(startIndex, offsetBy: r.upperBound)
    return String(self[start ..< end])
  }

  subscript (r: CountableClosedRange<Int>) -> String {
    let startIndex =  self.index(self.startIndex, offsetBy: r.lowerBound)
    let endIndex = self.index(startIndex, offsetBy: r.upperBound - r.lowerBound)
    return String(self[startIndex...endIndex])
  }
}

How to use it:

"abcde"[0] --> "a"

"abcde"[0...2] --> "abc"

"abcde"[2..<4] --> "cd"

Center a H1 tag inside a DIV

You can add line-height:51px to #AlertDiv h1 if you know it's only ever going to be one line. Also add text-align:center to #AlertDiv.

#AlertDiv {
    top:198px;
    left:365px;
    width:62px;
    height:51px;
    color:white;
    position:absolute;
    text-align:center;
    background-color:black;
}

#AlertDiv h1 {
    margin:auto;
    line-height:51px;
    vertical-align:middle;
}

The demo below also uses negative margins to keep the #AlertDiv centered on both axis, even when the window is resized.

Demo: jsfiddle.net/KaXY5

IntelliJ IDEA generating serialVersionUID

Easiest modern method: Alt+Enter on

private static final long serialVersionUID = ;

IntelliJ will underline the space after the =. put your cursor on it and hit alt+Enter (Option+Enter on Mac). You'll get a popover that says "Randomly Change serialVersionUID Initializer". Just hit enter, and it'll populate that space with a random long.

Generate a range of dates using SQL

Another simple way to get 365 days from today would be:

SELECT (TRUNC(sysdate) + (LEVEL-366)) AS DATE_ID
FROM DUAL connect by level <=( (sysdate)-(sysdate-366));

Using Alert in Response.Write Function in ASP.NET

You can simply write

try
 {
    //Your Logic and code
 }
 catch (Exception ex)
 {
    //Error message in  alert box
    Response.Write("<script>alert('Error :" +ex.Message+"');</script>");
 }

it will work fine

Operation Not Permitted when on root - El Capitan (rootless disabled)

Correct solution is to copy or install to /usr/local/bin not /usr/bin.This is due to System Integrity Protection (SIP). SIP makes /usr/bin read-only but leaves /usr/local as read-write.

SIP should not be disabled as stated in the answer above because it adds another layer of protection against malware gaining root access. Here is a complete explanation of what SIP does and why it is useful.

As suggested in this answer one should not disable SIP (rootless mode) "It is not recommended to disable rootless mode! The best practice is to install custom stuff to "/usr/local" only."

What's the difference between "Request Payload" vs "Form Data" as seen in Chrome dev tools Network tab

The Request Payload - or to be more precise: payload body of a HTTP Request - is the data normally send by a POST or PUT Request. It's the part after the headers and the CRLF of a HTTP Request.

A request with Content-Type: application/json may look like this:

POST /some-path HTTP/1.1
Content-Type: application/json

{ "foo" : "bar", "name" : "John" }

If you submit this per AJAX the browser simply shows you what it is submitting as payload body. That’s all it can do because it has no idea where the data is coming from.

If you submit a HTML-Form with method="POST" and Content-Type: application/x-www-form-urlencoded or Content-Type: multipart/form-data your request may look like this:

POST /some-path HTTP/1.1
Content-Type: application/x-www-form-urlencoded

foo=bar&name=John

In this case the form-data is the request payload. Here the Browser knows more: it knows that bar is the value of the input-field foo of the submitted form. And that’s what it is showing to you.

So, they differ in the Content-Type but not in the way data is submitted. In both cases the data is in the message-body. And Chrome distinguishes how the data is presented to you in the Developer Tools.

Android Completely transparent Status Bar?

add these lines into your Activity before the setContentView()

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
    Window w = getWindow();
    w.setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS, WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
}

add these 2 lines into your AppTheme

<item name="android:windowTranslucentStatus">true</item>
<item name="android:windowTranslucentNavigation">true</item>

and last thing your minSdkVersion must b 19

minSdkVersion 19

How to call Stored Procedure in a View?

You would have to script the View like below. You would essentially write the results of your proc to a table var or temp table, then select into the view.

Edit - If you can change your stored procedure to a Table Value function, it would eliminate the step of selecting to a temp table.

**Edit 2 ** - Comments are correct that a sproc cannot be read into a view like I suggested. Instead, convert your proc to a table-value function as mentioned in other posts and select from that:

create view sampleView
as select field1, field2, ... 
from dbo.MyTableValueFunction

I apologize for the confusion

How do I check if a string contains another string in Objective-C?

In case of swift, this can be used

let string = "Package #23"
if string.containsString("Package #") {
    //String contains substring
}
else {
    //String does not contain substring
}

Foreign key referring to primary keys across multiple tables?

Yes, it is possible. You will need to define 2 FKs for 3rd table. Each FK pointing to the required field(s) of one table (ie 1 FK per foreign table).

HTML embed autoplay="false", but still plays automatically

<embed ... autostart="0">

Replace false with 0

How to change folder with git bash?

if you are on windows then you can do a right click from the folder where you want to use git bash and select "GIT BASH HERE". enter image description here

Should switch statements always contain a default clause?

I disagree with the most voted answer of Vanwaril above.

Any code adds complexity. Also tests and documentation must be done for it. So it is always good if you can program using less code. My opinion is that I use a default clause for non-exhaustive switch statements while I use no default clause for exhaustive switch statements. To be sure that I did that right I use a static code analysis tool. So let's go into the details:

  1. Nonexhaustive switch statements: Those should always have a default value. As the name suggests those are statements which do not cover all possible values. This also might not be possible, e.g. a switch statement on an integer value or on a String. Here I would like to use the example of Vanwaril (It should be mentioned that I think he used this example to make a wrong suggestion. I use it here to state the opposite --> Use a default statement):

    switch(keystroke)
    {
      case 'w':
        // move up
      case 'a':
        // move left
      case 's':
        // move down
      case 'd':
        // move right
      default:          
        // cover all other values of the non-exhaustive switch statement
    }
    

    The player could press any other key. Then we could not do anything (this can be shown in the code just by adding a comment to the default case) or it should for example print something on the screen. This case is relevant as it may happen.

  2. Exhaustive switch statements: Those switch statements cover all possible values, e.g. a switch statement on an enumeration of grade system types. When developing code the first time it is easy to cover all values. However, as we are humans there is a small chance to forget some. Additionally if you add an enum value later such that all switch statements have to be adapted to make them exhaustive again opens the path to error hell. The simple solution is a static code analysis tool. The tool should check all switch statements and check if they are exhaustive or if they have a default value. Here an example for an exhaustive switch statement. First we need an enum:

    public enum GradeSystemType {System1To6, SystemAToD, System0To100}
    

    Then we need a variable of this enum like GradeSystemType type = .... An exhaustive switch statement would then look like this:

    switch(type)
    {
      case GradeSystemType.System1To6:
        // do something
      case GradeSystemType.SystemAToD:
        // do something
      case GradeSystemType.System0To100:
        // do something
    }
    

    So if we extend the GradeSystemType by for example System1To3 the static code analysis tool should detect that there is no default clause and the switch statement is not exhaustive so we are save.

Just one additional thing. If we always use a default clause it might happen that the static code analysis tool is not capable of detecting exhaustive or non-exhaustive switch statements as it always detects the default clause. This is super bad as we will not be informed if we extend the enum by another value and forget to add it to one switch statement.

Ruby array to string conversion

> puts "'"+['12','34','35','231']*"','"+"'"
'12','34','35','231'

> puts ['12','34','35','231'].inspect[1...-1].gsub('"',"'")
'12', '34', '35', '231'

Oracle Not Equals Operator

The difference is :

"If you use !=, it returns sub-second. If you use <>, it takes 7 seconds to return. Both return the right answer."

Oracle not equals (!=) SQL operator

Regards

Android - How to decode and decompile any APK file?

You can try this website http://www.decompileandroid.com Just upload the .apk file and rest of it will be done by this site.

Plot correlation matrix using pandas

For completeness, the simplest solution i know with seaborn as of late 2019, if one is using Jupyter:

import seaborn as sns
sns.heatmap(dataframe.corr())

Difference between map and collect in Ruby?

Ruby aliases the method Array#map to Array#collect; they can be used interchangeably. (Ruby Monk)

In other words, same source code :

               static VALUE
rb_ary_collect(VALUE ary)
{
long i;
VALUE collect;

RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
collect = rb_ary_new2(RARRAY_LEN(ary));
for (i = 0; i < RARRAY_LEN(ary); i++) {
    rb_ary_push(collect, rb_yield(RARRAY_AREF(ary, i)));
}
return collect;
}

http://ruby-doc.org/core-2.2.0/Array.html#method-i-map

How to update Xcode from command line

To those having this issue after update to Catalina, just execute this command on your terminal

sudo rm -rf /Library/Developer/CommandLineTools; xcode-select --install;

Change onclick action with a Javascript function

You could try changing the button attribute like this:

element.setAttribute( "onClick", "javascript: Boo();" );

How to test if a file is a directory in a batch script?

One issue with using %%~si\NUL method is that there is the chance that it guesses wrong. Its possible to have a filename shorten to the wrong file. I don't think %%~si resolves the 8.3 filename, but guesses it, but using string manipulation to shorten the filepath. I believe if you have similar file paths it may not work.

An alternative method:

dir /AD %F% 2>&1 | findstr /C:"Not Found">NUL:&&(goto IsFile)||(goto IsDir)

:IsFile
  echo %F% is a file
  goto done

:IsDir
  echo %F% is a directory
  goto done

:done

You can replace (goto IsFile)||(goto IsDir) with other batch commands:
(echo Is a File)||(echo is a Directory)

Getting Java version at runtime

The simplest way (java.specification.version):

double version = Double.parseDouble(System.getProperty("java.specification.version"));

if (version == 1.5) {
    // 1.5 specific code
} else {
    // ...
}

or something like (java.version):

String[] javaVersionElements = System.getProperty("java.version").split("\\.");

int major = Integer.parseInt(javaVersionElements[1]);

if (major == 5) {
    // 1.5 specific code
} else {
    // ...
}

or if you want to break it all up (java.runtime.version):

String discard, major, minor, update, build;

String[] javaVersionElements = System.getProperty("java.runtime.version").split("\\.|_|-b");

discard = javaVersionElements[0];
major   = javaVersionElements[1];
minor   = javaVersionElements[2];
update  = javaVersionElements[3];
build   = javaVersionElements[4];

Can a java lambda have more than 1 parameter?

You could also use jOOL library - https://github.com/jOOQ/jOOL

It has already prepared function interfaces with different number of parameters. For instance, you could use org.jooq.lambda.function.Function3, etc from Function0 up to Function16.

How to import the class within the same directory or sub directory?

To make it more simple to understand:

Step 1: lets go to one directory, where all will be included

$ cd /var/tmp

Step 2: now lets make a class1.py file which has a class name Class1 with some code

$ cat > class1.py <<\EOF
class Class1:
    OKBLUE = '\033[94m'
    ENDC = '\033[0m'
    OK = OKBLUE + "[Class1 OK]: " + ENDC
EOF

Step 3: now lets make a class2.py file which has a class name Class2 with some code

$ cat > class2.py <<\EOF
class Class2:
    OKBLUE = '\033[94m'
    ENDC = '\033[0m'
    OK = OKBLUE + "[Class2 OK]: " + ENDC
EOF

Step 4: now lets make one main.py which will be execute once to use Class1 and Class2 from 2 different files

$ cat > main.py <<\EOF
"""this is how we are actually calling class1.py and  from that file loading Class1"""
from class1 import Class1 
"""this is how we are actually calling class2.py and  from that file loading Class2"""
from class2 import Class2

print Class1.OK
print Class2.OK
EOF

Step 5: Run the program

$ python main.py

The output would be

[Class1 OK]: 
[Class2 OK]:

Powershell Get-ChildItem most recent file in directory

Yes I think this would be quicker.

Get-ChildItem $folder | Sort-Object -Descending -Property LastWriteTime -Top 1 

Where does Jenkins store configuration files for the jobs it runs?

For the sake of completeness: macOS High Sierra, Jenkins 2.x, installation via Homebrew
~/.jenkins/jobs/{project_name}/config.xml

Complete overview about jenkins home: https://wiki.jenkins.io/display/JENKINS/Administering+Jenkins

Ubuntu - Run command on start-up with "sudo"

Edit the tty configuration in /etc/init/tty*.conf with a shellscript as a parameter :

(...)
exec /sbin/getty -n -l  theInputScript.sh -8 38400 tty1
(...)

This is assuming that we're editing tty1 and the script that reads input is theInputScript.sh.

A word of warning this script is run as root, so when you are inputing stuff to it you have root priviliges. Also append a path to the location of the script.

Important: the script when it finishes, has to invoke the /sbin/login otherwise you wont be able to login in the terminal.

Angular exception: Can't bind to 'ngForIn' since it isn't a known native property

Since this is at least the third time I've wasted more than 5 min on this problem I figured I'd post the Q & A. I hope it helps someone else down the road... probably me!

I typed in instead of of in the ngFor expression.

Befor 2-beta.17, it should be:

<div *ngFor="#talk of talks">

As of beta.17, use the let syntax instead of #. See the UPDATE further down for more info.


Note that the ngFor syntax "desugars" into the following:

<template ngFor #talk [ngForOf]="talks">
  <div>...</div>
</template>

If we use in instead, it turns into

<template ngFor #talk [ngForIn]="talks">
  <div>...</div>
</template>

Since ngForIn isn't an attribute directive with an input property of the same name (like ngIf), Angular then tries to see if it is a (known native) property of the template element, and it isn't, hence the error.

UPDATE - as of 2-beta.17, use the let syntax instead of #. This updates to the following:

<div *ngFor="let talk of talks">

Note that the ngFor syntax "desugars" into the following:

<template ngFor let-talk [ngForOf]="talks">
  <div>...</div>
</template>

If we use in instead, it turns into

<template ngFor let-talk [ngForIn]="talks">
  <div>...</div>
</template>

DevTools failed to load SourceMap: Could not load content for chrome-extension

I do not think the warnings you have received are related. I had the same warnings which turned out to be the chrome extension React Dev Tools. Removed the extension and the errors have gone.

How do I extract text that lies between parentheses (round brackets)?

Use a Regular Expression:

string test = "(test)"; 
string word = Regex.Match(test, @"\((\w+)\)").Groups[1].Value;
Console.WriteLine(word);

HTML table sort

Another approach to sort HTML table. (based on W3.JS HTML Sort)

_x000D_
_x000D_
let tid = "#usersTable";_x000D_
let headers = document.querySelectorAll(tid + " th");_x000D_
_x000D_
// Sort the table element when clicking on the table headers_x000D_
headers.forEach(function(element, i) {_x000D_
  element.addEventListener("click", function() {_x000D_
    w3.sortHTML(tid, ".item", "td:nth-child(" + (i + 1) + ")");_x000D_
  });_x000D_
});
_x000D_
th {_x000D_
  cursor: pointer;_x000D_
  background-color: coral;_x000D_
}
_x000D_
<script src="https://www.w3schools.com/lib/w3.js"></script>_x000D_
<link href="https://www.w3schools.com/w3css/4/w3.css" rel="stylesheet" />_x000D_
<p>Click the <strong>table headers</strong> to sort the table accordingly:</p>_x000D_
_x000D_
<table id="usersTable" class="w3-table-all">_x000D_
  <!--     _x000D_
  <tr>_x000D_
    <th onclick="w3.sortHTML('#usersTable', '.item', 'td:nth-child(1)')">Name</th>_x000D_
    <th onclick="w3.sortHTML('#usersTable', '.item', 'td:nth-child(2)')">Address</th>_x000D_
    <th onclick="w3.sortHTML('#usersTable', '.item', 'td:nth-child(3)')">Sales Person</th>_x000D_
  </tr> _x000D_
  -->_x000D_
  <tr>_x000D_
    <th>Name</th>_x000D_
    <th>Address</th>_x000D_
    <th>Sales Person</th>_x000D_
  </tr>_x000D_
_x000D_
  <tr class="item">_x000D_
    <td>user:2911002</td>_x000D_
    <td>UK</td>_x000D_
    <td>Melissa</td>_x000D_
  </tr>_x000D_
  <tr class="item">_x000D_
    <td>user:2201002</td>_x000D_
    <td>France</td>_x000D_
    <td>Justin</td>_x000D_
  </tr>_x000D_
  <tr class="item">_x000D_
    <td>user:2901092</td>_x000D_
    <td>San Francisco</td>_x000D_
    <td>Judy</td>_x000D_
  </tr>_x000D_
  <tr class="item">_x000D_
    <td>user:2801002</td>_x000D_
    <td>Canada</td>_x000D_
    <td>Skipper</td>_x000D_
  </tr>_x000D_
  <tr class="item">_x000D_
    <td>user:2901009</td>_x000D_
    <td>Christchurch</td>_x000D_
    <td>Alex</td>_x000D_
  </tr>_x000D_
_x000D_
</table>
_x000D_
_x000D_
_x000D_

How can we run a test method with multiple parameters in MSTest?

I couldn't get The DataRowAttribute to work in Visual Studio 2015, and this is what I ended up with:

[TestClass]
public class Tests
{
    private Foo _toTest;

    [TestInitialize]
    public void Setup()
    {
        this._toTest = new Foo();
    }

    [TestMethod]
    public void ATest()
    {
        this.Perform_ATest(1, 1, 2);
        this.Setup();

        this.Perform_ATest(100, 200, 300);
        this.Setup();

        this.Perform_ATest(817001, 212, 817213);
        this.Setup();
    }

    private void Perform_ATest(int a, int b, int expected)
    {
        // Obviously this would be way more complex...

        Assert.IsTrue(this._toTest.Add(a,b) == expected);
    }
}

public class Foo
{
    public int Add(int a, int b)
    {
        return a + b;
    }
}

The real solution here is to just use NUnit (unless you're stuck in MSTest like I am in this particular instance).

How do I run pip on python for windows?

Maybe you'd like try run pip in Python shell like this:

>>> import pip
>>> pip.main(['install', 'requests'])

This will install requests package using pip.


Because pip is a module in standard library, but it isn't a built-in function(or module), so you need import it.

Other way, you should run pip in system shell(cmd. If pip is in path).

When to use "new" and when not to, in C++?

New is always used to allocate dynamic memory, which then has to be freed.

By doing the first option, that memory will be automagically freed when scope is lost.

Point p1 = Point(0,0); //This is if you want to be safe and don't want to keep the memory outside this function.

Point* p2 = new Point(0, 0); //This must be freed manually. with...
delete p2;

How to change Hash values?

Since ruby 2.4.0 you can use native Hash#transform_values method:

hash = {"a" => "b", "c" => "d"}
new_hash = hash.transform_values(&:upcase)
# => {"a" => "B", "c" => "D"}

There is also destructive Hash#transform_values! version.

Trim a string based on the string length

tl;dr

You seem to be asking for an ellipsis () character in the last place, when truncating. Here is a one-liner to manipulate your input string.

String input = "abcdefghijkl";
String output = ( input.length () > 10 ) ? input.substring ( 0 , 10 - 1 ).concat ( "…" ) : input;

See this code run live at IdeOne.com.

abcdefghi…

Ternary operator

We can make a one-liner by using the ternary operator.

String input = "abcdefghijkl" ;

String output = 
    ( input.length() > 10 )          // If too long…
    ?                                
    input     
    .substring( 0 , 10 - 1 )         // Take just the first part, adjusting by 1 to replace that last character with an ellipsis.
    .concat( "…" )                   // Add the ellipsis character.
    :                                // Or, if not too long…
    input                            // Just return original string.
;

See this code run live at IdeOne.com.

abcdefghi…

Java streams

The Java Streams facility makes this interesting, as of Java 9 and later. Interesting, but maybe not the best approach.

We use code points rather than char values. The char type is legacy, and is limited to the a subset of all possible Unicode characters.

String input = "abcdefghijkl" ;
int limit = 10 ;
String output =
        input
                .codePoints()
                .limit( limit )
                .collect(                                    // Collect the results of processing each code point.
                        StringBuilder::new,                  // Supplier<R> supplier
                        StringBuilder::appendCodePoint,      // ObjIntConsumer<R> accumulator
                        StringBuilder::append                // BiConsumer<R,?R> combiner
                )
                .toString()
        ;

If we had excess characters truncated, replace the last character with an ellipsis.

if ( input.length () > limit )
{
    output = output.substring ( 0 , output.length () - 1 ) + "…";
}

If only I could think of a way to put together the stream line with the "if over limit, do ellipsis" part.

In android how to set navigation drawer header image and name programmatically in class file?

It's and old post, but it's new for me. So, it is straight forward! In this part of the code:

 public boolean onNavigationItemSelected(MenuItem item) {

} , I bound an ImageView to the LinearLayout, which contains the ImageView from the example, listed below. Mind: it's the same code you get when you start a new project, and choose the template "Navigation Drawer Activity":

<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingTop="@dimen/nav_header_vertical_spacing"
android:src="@android:drawable/sym_def_app_icon" />

I gave the LinearLayout and ID, inside nav_header_main.xml (in my case I chose 'navigation_header_container' , so it went this way:

LinearLayout lV = (LinearLayout) findViewById(R.id.navigation_header_container);

    ivCloseDrawer = (ImageView) lV.findViewById(R.id.imageView);
    ivCloseDrawer.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            drawer.closeDrawer(GravityCompat.START);
        }
    });

Note: I have a private ImageView ivCloseDrawer declared at the top, before onCreate (MainActivity).

It worked fine! Hope it helps, Best Regards.

Make iframe automatically adjust height according to the contents without using scrollbar?

Avoid inline JavaScript; you can use a class:

<iframe src="..." frameborder="0" scrolling="auto" class="iframe-full-height"></iframe>

And reference it with jQuery:

$('.iframe-full-height').on('load', function(){
    this.style.height=this.contentDocument.body.scrollHeight +'px';
});

How to get raw text from pdf file using java

Using pdfbox we can achive this

Example :

public static void main(String args[]) {

    PDFParser parser = null;
    PDDocument pdDoc = null;
    COSDocument cosDoc = null;
    PDFTextStripper pdfStripper;

    String parsedText;
    String fileName = "E:\\Files\\Small Files\\PDF\\JDBC.pdf";
    File file = new File(fileName);
    try {
        parser = new PDFParser(new FileInputStream(file));
        parser.parse();
        cosDoc = parser.getDocument();
        pdfStripper = new PDFTextStripper();
        pdDoc = new PDDocument(cosDoc);
        parsedText = pdfStripper.getText(pdDoc);
        System.out.println(parsedText.replaceAll("[^A-Za-z0-9. ]+", ""));
    } catch (Exception e) {
        e.printStackTrace();
        try {
            if (cosDoc != null)
                cosDoc.close();
            if (pdDoc != null)
                pdDoc.close();
        } catch (Exception e1) {
            e1.printStackTrace();
        }

    }
}

Can I get Unix's pthread.h to compile in Windows?

Just pick up the TDM-GCC 64x package. (It constains both the 32 and 64 bit versions of the MinGW toolchain and comes within a neat installer.) More importantly, it contains something called the "winpthread" library.

It comprises of the pthread.h header, libwinpthread.a, libwinpthread.dll.a static libraries for both 32-bit and 64-bit and the required .dlls libwinpthread-1.dll and libwinpthread_64-1.dll(this, as of 01-06-2016).

You'll need to link to the libwinpthread.a library during build. Other than that, your code can be the same as for native Pthread code on Linux. I've so far successfully used it to compile a few basic Pthread programs in 64-bit on windows.

Alternatively, you can use the following library which wraps the windows threading API into the pthreads API: pthreads-win32.

The above two seem to be the most well known ways for this.

Hope this helps.

Convert date to UTC using moment.js

moment.utc(date).format(...); 

is the way to go, since

moment().utc(date).format(...);

does behave weird...

How to convert JSON data into a Python object

There are multiple viable answers already, but there are some minor libraries made by individuals that can do the trick for most users.

An example would be json2object. Given a defined class, it deserialises json data to your custom model, including custom attributes and child objects.

Its use is very simple. An example from the library wiki:

_x000D_
_x000D_
from json2object import jsontoobject as jo

class Student:
    def __init__(self):
        self.firstName = None
        self.lastName = None
        self.courses = [Course('')]

class Course:
    def __init__(self, name):
        self.name = name

data = '''{
"firstName": "James",
"lastName": "Bond",
"courses": [{
    "name": "Fighting"},
    {
    "name": "Shooting"}
    ]
}
'''

model = Student()
result = jo.deserialize(data, model)
print(result.courses[0].name)
_x000D_
_x000D_
_x000D_

How to change the integrated terminal in visual studio code or VSCode

I was successful via settings > Terminal > Integrated > Shell: Linux

from there I edited the path of the shell to be /bin/zsh from the default /bin/bash

  • there are also options for OSX and Windows as well

screencap of vs settings view

@charlieParker - here's what i'm seeing for available commands in the command pallette

enter image description here

Importing csv file into R - numeric values read as characters

I had a similar problem. Based on Joshua's premise that excel was the problem I looked at it and found that the numbers were formatted with commas between every third digit. Reformatting without commas fixed the problem.

Link to reload current page

<a href=".">refresh current page</a>

or if you want to pass parameters:

<a href=".?curreny='usd'">refresh current page</a>

Python 3 - Encode/Decode vs Bytes/Str

To add to add to the previous answer, there is even a fourth way that can be used

import codecs
encoded4 = codecs.encode(original, 'utf-8')
print(encoded4)

Is List<Dog> a subclass of List<Animal>? Why are Java generics not implicitly polymorphic?

The problem has been well-identified. But there's a solution; make doSomething generic:

<T extends Animal> void doSomething<List<T> animals) {
}

now you can call doSomething with either List<Dog> or List<Cat> or List<Animal>.

Zsh: Conda/Pip installs command not found

MAC OS Users:

  1. brew install anaconda
  2. Add export PATH="/usr/local/anaconda3/bin:$PATH" to top of ~/.zshrc
  3. source ~/.zshrc OR restart terminal

Test it. Bingo Bango.

How to save S3 object to a file using boto3

Note: I'm assuming you have configured authentication separately. Below code is to download the single object from the S3 bucket.

import boto3

#initiate s3 client 
s3 = boto3.resource('s3')

#Download object to the file    
s3.Bucket('mybucket').download_file('hello.txt', '/tmp/hello.txt')

jQuery: how to change title of document during .ready()?

<script type="text/javascript">
$(document).ready(function() {

    $(this).attr("title", "sometitle");

});
</script>

VBA copy rows that meet criteria to another sheet

You need to specify workseet. Change line

If Worksheet.Cells(i, 1).Value = "X" Then

to

If Worksheets("Sheet2").Cells(i, 1).Value = "X" Then

UPD:

Try to use following code (but it's not the best approach. As @SiddharthRout suggested, consider about using Autofilter):

Sub LastRowInOneColumn()
   Dim LastRow As Long
   Dim i As Long, j As Long

   'Find the last used row in a Column: column A in this example
   With Worksheets("Sheet2")
      LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row
   End With

   MsgBox (LastRow)
   'first row number where you need to paste values in Sheet1'
   With Worksheets("Sheet1")
      j = .Cells(.Rows.Count, "A").End(xlUp).Row + 1
   End With 

   For i = 1 To LastRow
       With Worksheets("Sheet2")
           If .Cells(i, 1).Value = "X" Then
               .Rows(i).Copy Destination:=Worksheets("Sheet1").Range("A" & j)
               j = j + 1
           End If
       End With
   Next i
End Sub

MySQL error #1054 - Unknown column in 'Field List'

I had this error aswell.

I am working in mysql workbench. When giving the values they have to be inside "". That solved it for me.

How to get row count in an Excel file using POI library?

getLastRowNum() return index of last row.

So if you wants to know total number of row = getLastRowNum() +1.

I hope this will work.

int rowTotal = sheet.getLastRowNum() +1;

How to send data with angularjs $http.delete() request?

My suggestion:

$http({
    method: 'DELETE',
    url: '/roles/' + roleid,
    data: {
        user: userId
    },
    headers: {
        'Content-type': 'application/json;charset=utf-8'
    }
})
.then(function(response) {
    console.log(response.data);
}, function(rejection) {
    console.log(rejection.data);
});

Pass an array of integers to ASP.NET Web API?

You may try this code for you to take comma separated values / an array of values to get back a JSON from webAPI

 public class CategoryController : ApiController
 {
     public List<Category> Get(String categoryIDs)
     {
         List<Category> categoryRepo = new List<Category>();

         String[] idRepo = categoryIDs.Split(',');

         foreach (var id in idRepo)
         {
             categoryRepo.Add(new Category()
             {
                 CategoryID = id,
                 CategoryName = String.Format("Category_{0}", id)
             });
         }
         return categoryRepo;
     }
 }

 public class Category
 {
     public String CategoryID { get; set; }
     public String CategoryName { get; set; }
 } 

Output :

[
{"CategoryID":"4","CategoryName":"Category_4"}, 
{"CategoryID":"5","CategoryName":"Category_5"}, 
{"CategoryID":"3","CategoryName":"Category_3"} 
]

How to get input field value using PHP

function get_input_tags($html)
{
    $post_data = array();

    // a new dom object
    $dom = new DomDocument; 

    //load the html into the object
    $dom->loadHTML($html); 
    //discard white space
    $dom->preserveWhiteSpace = false; 

    //all input tags as a list
    $input_tags = $dom->getElementsByTagName('input'); 

    //get all rows from the table
    for ($i = 0; $i < $input_tags->length; $i++) 
    {
        if( is_object($input_tags->item($i)) )
        {
            $name = $value = '';
            $name_o = $input_tags->item($i)->attributes->getNamedItem('name');
            if(is_object($name_o))
            {
                $name = $name_o->value;

                $value_o = $input_tags->item($i)->attributes->getNamedItem('value');
                if(is_object($value_o))
                {
                    $value = $input_tags->item($i)->attributes->getNamedItem('value')->value;
                }

                $post_data[$name] = $value;
            }
        }
    }

    return $post_data; 
}

error_reporting(~E_WARNING);
$html = file_get_contents("https://accounts.google.com/ServiceLoginAuth");

print_r(get_input_tags($html));

How to show alert message in mvc 4 controller?

Use this:

return JavaScript(alert("Hello this is an alert"));

or:

return Content("<script language='javascript' type='text/javascript'>alert('Thanks for Feedback!');</script>");

Disabling vertical scrolling in UIScrollView

yes, pt2ph8's answer is right,

but if for some strange reason your contentSize should be higher than the UIScrollView, you can disable the vertical scrolling implementing the UIScrollView protocol method

 -(void)scrollViewDidScroll:(UIScrollView *)aScrollView;

just add this in your UIViewController

float oldY; // here or better in .h interface

- (void)scrollViewDidScroll:(UIScrollView *)aScrollView
{
    [aScrollView setContentOffset: CGPointMake(aScrollView.contentOffset.x, oldY)];
    // or if you are sure you wanna it always on top:
    // [aScrollView setContentOffset: CGPointMake(aScrollView.contentOffset.x, 0)];
}

it's just the method called when the user scroll your UIScrollView, and doing so you force the content of it to have always the same .y

How to update primary key

Don't update the primary key. It could cause a lot of problems for you keeping your data intact, if you have any other tables referencing it.

Ideally, if you want a unique field that is updateable, create a new field.

Visual studio code CSS indentation and formatting

Beautify css/sass/scss/less

to run this

enter alt+shift+f

or

press F1 or ctrl+shift+p and then enter beautify ..

enter image description here


an another one - JS-CSS-HTML Formatter

i think both this extension uses js-beautify internally

Access And/Or exclusions

Seeing that it appears you are running using the SQL syntax, try with the correct wild card.

SELECT * FROM someTable WHERE (someTable.Field NOT LIKE '%RISK%') AND (someTable.Field NOT LIKE '%Blah%') AND someTable.SomeOtherField <> 4; 

How do I view executed queries within SQL Server Management Studio?

More clear query, targeting Studio sql queries is :

SELECT text  FROM sys.dm_exec_sessions es
  INNER JOIN sys.dm_exec_connections ec
      ON es.session_id = ec.session_id
  CROSS APPLY sys.dm_exec_sql_text(ec.most_recent_sql_handle) 
  where program_name like '%Query'

Tablix: Repeat header rows on each page not working - Report Builder 3.0

It depends on the tablix structure you are using. In a table, for example, you do not have column groups, so Reporting Services does not recognize which textboxes are the column headers and setting RepeatColumnHeaders property to True doesn't work.

Instead, you need to:

  1. Open Advanced Mode in the Groupings pane. (Click the arrow to the right of the Column Groups and select Advanced Mode.)
    • Screenshot
  2. In the Row Groups area (not Column Groups), click on a Static group, which highlights the corresponding textbox in the tablix. Click through each Static group until it highlights the leftmost column header. This is generally the first Static group listed.
  3. In the Properties window, set the RepeatOnNewPage property to True.
    • Screenshot
  4. Make sure that the KeepWithGroup property is set to After.

The KeepWithGroup property specifies which group to which the static member needs to stick. If set to After then the static member sticks with the group after it, or below it, acting as a group header. If set to Before, then the static member sticks with the group before, or above it, acting as a group footer. If set to None, Reporting Services decides where to put the static member.

Now when you view the report, the column headers repeat on each page of the tablix.

This video shows how to set it exactly as the answer described.

how to apply click event listener to image in android

In xml:

<ImageView  
 android:clickable="true"  
 android:onClick="imageClick"  
 android:src="@drawable/myImage">  
 </ImageView>  

In code

 public class Test extends Activity {  
  ........  
  ........  
 public void imageClick(View view) {  
  //Implement image click function  
 }  

ASP.NET MVC Razor pass model to layout

this is pretty basic stuff, all you need to do is to create a base view model and make sure ALL! and i mean ALL! of your views that will ever use that layout will receive views that use that base model!

public class SomeViewModel : ViewModelBase
{
    public bool ImNotEmpty = true;
}

public class EmptyViewModel : ViewModelBase
{
}

public abstract class ViewModelBase
{
}

in the _Layout.cshtml:

@model Models.ViewModelBase
<!DOCTYPE html>
  <html>
  and so on...

in the the Index (for example) method in the home controller:

    public ActionResult Index()
    {
        var model = new SomeViewModel()
        {
        };
        return View(model);
    }

the Index.cshtml:

@model Models.SomeViewModel

@{
  ViewBag.Title = "Title";
  Layout = "~/Views/Shared/_Layout.cshtml";
}

<div class="row">

i disagree that passing a model to the _layout is an error, some user info can be passed and the data can be populate in the controllers inheritance chain so only one implementation is needed.

obviously for more advanced purpose you should consider creating custom static contaxt using injection and include that model namespace in the _Layout.cshtml.

but for basic users this will do the trick

How to convert Nvarchar column to INT

You can always use the ISNUMERIC helper function to convert only what's really numeric:

SELECT
     CAST(A.my_NvarcharColumn AS BIGINT)
FROM 
     A
WHERE
     ISNUMERIC(A.my_NvarcharColumn) = 1

Simultaneously merge multiple data.frames in a list

I will reuse the data example from @PaulRougieux

x <- data_frame(i = c("a","b","c"), j = 1:3)
y <- data_frame(i = c("b","c","d"), k = 4:6)
z <- data_frame(i = c("c","d","a"), l = 7:9)

Here's a short and sweet solution using purrr and tidyr

library(tidyverse)

 list(x, y, z) %>% 
  map_df(gather, key=key, value=value, -i) %>% 
  spread(key, value)

For loop for HTMLCollection elements

you can add this two lines:

HTMLCollection.prototype.forEach = Array.prototype.forEach;
NodeList.prototype.forEach = Array.prototype.forEach;

HTMLCollection is return by getElementsByClassName and getElementsByTagName

NodeList is return by querySelectorAll

Like this you can do a forEach:

var selections = document.getElementsByClassName('myClass');

/* alternative :
var selections = document.querySelectorAll('.myClass');
*/

selections.forEach(function(element, i){
//do your stuffs
});

Netbeans installation doesn't find JDK

If you are certain that you have a JDK installed (and not a JRE), you can specify the location of the JDK on the commandline when starting the installer (as mentioned in the error message you get).

These FAQ entries might also help you:

http://wiki.netbeans.org/FaqInstallJavahome
http://wiki.netbeans.org/FaqSuitableJvmNotFound

React - Preventing Form Submission

In your onTestClick function, pass in the event argument and call preventDefault() on it.

function onTestClick(e) {
    e.preventDefault();
}

Is it possible to set an object to null?

You can set any pointer to NULL, though NULL is simply defined as 0 in C++:

myObject *foo = NULL;

Also note that NULL is defined if you include standard headers, but is not built into the language itself. If NULL is undefined, you can use 0 instead, or include this:

#ifndef NULL
#define NULL 0
#endif

As an aside, if you really want to set an object, not a pointer, to NULL, you can read about the Null Object Pattern.

How can I make a float top with CSS?

This works, apply in ul:

display:flex;
flex-direction:column;
flex-wrap:wrap;

Getting only Month and Year from SQL DATE

I had a specific requirement to do something similar where it would show month-year which can be done by the following:

SELECT DATENAME(month, GETDATE()) + '-' + CAST(YEAR(GETDATE()) AS nvarchar) AS 'Month-Year'

In my particular case, I needed to have it down to the 3 letter month abreviation with a 2 digit year, looking something like this: SELECT LEFT(DATENAME(month, GETDATE()), 3) + '-' + CAST(RIGHT(YEAR(GETDATE()),2) AS nvarchar(2)) AS 'Month-Year'

Specifying trust store information in spring boot application.properties

When everything sounded so complicated, this command worked for me:

keytool -genkey -alias foo -keystore cacerts -dname cn=test -storepass changeit -keypass changeit

When a developer is in trouble, I believe a simple working solution snippet is more than enough for him. Later he could diagnose the root cause and basic understanding related to the issue.

Using global variables in a function

You can use a global variable within other functions by declaring it as global within each function that assigns a value to it:

globvar = 0

def set_globvar_to_one():
    global globvar    # Needed to modify global copy of globvar
    globvar = 1

def print_globvar():
    print(globvar)     # No need for global declaration to read value of globvar

set_globvar_to_one()
print_globvar()       # Prints 1

I imagine the reason for it is that, since global variables are so dangerous, Python wants to make sure that you really know that's what you're playing with by explicitly requiring the global keyword.

See other answers if you want to share a global variable across modules.

calculating number of days between 2 columns of dates in data frame

You could find the difference between dates in columns in a data frame by using the function difftime as follows:

df$diff_in_days<- difftime(df$datevar1 ,df$datevar2 , units = c("days"))

Entry point for Java applications: main(), init(), or run()?

The main method is the entry point of a Java application.

Specifically?when the Java Virtual Machine is told to run an application by specifying its class (by using the java application launcher), it will look for the main method with the signature of public static void main(String[]).

From Sun's java command page:

The java tool launches a Java application. It does this by starting a Java runtime environment, loading a specified class, and invoking that class's main method.

The method must be declared public and static, it must not return any value, and it must accept a String array as a parameter. The method declaration must look like the following:

public static void main(String args[])

For additional resources on how an Java application is executed, please refer to the following sources:

  1. Chapter 12: Execution from the Java Language Specification, Third Edition.
  2. Chapter 5: Linking, Loading, Initializing from the Java Virtual Machine Specifications, Second Edition.
  3. A Closer Look at the "Hello World" Application from the Java Tutorials.

The run method is the entry point for a new Thread or an class implementing the Runnable interface. It is not called by the Java Virutal Machine when it is started up by the java command.

As a Thread or Runnable itself cannot be run directly by the Java Virtual Machine, so it must be invoked by the Thread.start() method. This can be accomplished by instantiating a Thread and calling its start method in the main method of the application:

public class MyRunnable implements Runnable
{
    public void run()
    {
        System.out.println("Hello World!");
    }

    public static void main(String[] args)
    {
        new Thread(new MyRunnable()).start();
    }
}

For more information and an example of how to start a subclass of Thread or a class implementing Runnable, see Defining and Starting a Thread from the Java Tutorials.


The init method is the first method called in an Applet or JApplet.

When an applet is loaded by the Java plugin of a browser or by an applet viewer, it will first call the Applet.init method. Any initializations that are required to use the applet should be executed here. After the init method is complete, the start method is called.

For more information about when the init method of an applet is called, please read about the lifecycle of an applet at The Life Cycle of an Applet from the Java Tutorials.

See also: How to Make Applets from the Java Tutorial.

Rails: How can I set default values in ActiveRecord?

class Item < ActiveRecord::Base
  def status
    self[:status] or ACTIVE
  end

  before_save{ self.status ||= ACTIVE }
end

Popup window in winform c#

This is not so easy because basically popups are not supported in windows forms. Although windows forms is based on win32 and in win32 popup are supported. If you accept a few tricks, following code will set you going with a popup. You decide if you want to put it to good use :

class PopupWindow : Control
{
    private const int WM_ACTIVATE = 0x0006;
    private const int WM_MOUSEACTIVATE = 0x0021;

    private Control ownerControl;

    public PopupWindow(Control ownerControl)
        :base()
    {
        this.ownerControl = ownerControl;
        base.SetTopLevel(true);
    }

    public Control OwnerControl
    {
        get
        {
            return (this.ownerControl as Control);
        }
        set
        {
            this.ownerControl = value;
        }
    }

    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams createParams = base.CreateParams;

            createParams.Style = WindowStyles.WS_POPUP |
                                 WindowStyles.WS_VISIBLE |
                                 WindowStyles.WS_CLIPSIBLINGS |
                                 WindowStyles.WS_CLIPCHILDREN |
                                 WindowStyles.WS_MAXIMIZEBOX |
                                 WindowStyles.WS_BORDER;
            createParams.ExStyle = WindowsExtendedStyles.WS_EX_LEFT |
                                   WindowsExtendedStyles.WS_EX_LTRREADING |
                                   WindowsExtendedStyles.WS_EX_RIGHTSCROLLBAR | 
                                   WindowsExtendedStyles.WS_EX_TOPMOST;

            createParams.Parent = (this.ownerControl != null) ? this.ownerControl.Handle : IntPtr.Zero;
            return createParams;
        }
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
    public static extern IntPtr SetActiveWindow(HandleRef hWnd);

    protected override void WndProc(ref Message m)
    {
        switch (m.Msg)
        {
            case WM_ACTIVATE:
                {
                    if ((int)m.WParam == 1)
                    {
                        //window is being activated
                        if (ownerControl != null)
                        {
                            SetActiveWindow(new HandleRef(this, ownerControl.FindForm().Handle));
                        }
                    }
                    break;
                }
            case WM_MOUSEACTIVATE:
                {
                    m.Result = new IntPtr(MouseActivate.MA_NOACTIVATE);
                    return;
                    //break;
                }
        }
        base.WndProc(ref m);
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);
        e.Graphics.FillRectangle(SystemBrushes.Info, 0, 0, Width, Height);
        e.Graphics.DrawString((ownerControl as VerticalDateScrollBar).FirstVisibleDate.ToLongDateString(), this.Font, SystemBrushes.InfoText, 2, 2);
    }
}

Experiment with it a bit, you have to play around with its position and its size. Use it wrong and nothing shows.

maven compilation failure

Try to use:

mvn clean package install

This command should install your artifacts in you local maven repo.

PS: I see that this is an old question, but it may be helpful for somebody in the future.

Javascript checkbox onChange

function calc()
{
  if (document.getElementById('xxx').checked) 
  {
      document.getElementById('totalCost').value = 10;
  } else {
      calculate();
  }
}

HTML

<input type="checkbox" id="xxx" name="xxx" onclick="calc();"/>

Reading Email using Pop3 in C#

You can also try Mail.dll mail component, it has SSL support, unicode, and multi-national email support:

using(Pop3 pop3 = new Pop3())
{
    pop3.Connect("mail.host.com");           // Connect to server and login
    pop3.Login("user", "password");

    foreach(string uid in pop3.GetAll())
    {
        IMail email = new MailBuilder()
            .CreateFromEml(pop3.GetMessageByUID(uid));
          Console.WriteLine( email.Subject );
    }
    pop3.Close(false);      
}

You can download it here at https://www.limilabs.com/mail

Please note that this is a commercial product I've created.

Split Java String by New Line

A new method lines has been introduced to String class in , which returns Stream<String>

Returns a stream of substrings extracted from this string partitioned by line terminators.

Line terminators recognized are line feed "\n" (U+000A), carriage return "\r" (U+000D) and a carriage return followed immediately by a line feed "\r\n" (U+000D U+000A).

Here are a few examples:

jshell> "lorem \n ipusm \n sit".lines().forEach(System.out::println)
lorem
 ipusm
 sit

jshell> "lorem \n ipusm \r  sit".lines().forEach(System.out::println)
lorem
 ipusm
  sit

jshell> "lorem \n ipusm \r\n  sit".lines().forEach(System.out::println)
lorem
 ipusm
  sit

String#lines()

Hibernate Criteria Restrictions AND / OR combination

think works

Criteria criteria = getSession().createCriteria(clazz); 
Criterion rest1= Restrictions.and(Restrictions.eq(A, "X"), 
           Restrictions.in("B", Arrays.asList("X",Y)));
Criterion rest2= Restrictions.and(Restrictions.eq(A, "Y"), 
           Restrictions.eq(B, "Z"));
criteria.add(Restrictions.or(rest1, rest2));

About the Full Screen And No Titlebar from manifest

If your Manifest.xml has the default android:theme="@style/AppTheme"

Go to res/values/styles.xml and change

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">

to

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

And the ActionBar is disappeared!

How to reset a select element with jQuery

$('#baba option:first').prop('selected',true);

Nowadays you best use .prop(): http://api.jquery.com/prop/

INSTALL_FAILED_USER_RESTRICTED : android studio using redmi 4 device

Xiaomi MIUI.

Options - Permissions - Install via USB (not the same item in Developers options!) then uncheck your disabled app

How can I check if a file exists in Perl?

if(-e $base_path){print "Something";}

would do the trick

sql query with multiple where statements

Can we see the structure of your table? If I am understanding this, then the assumption made by the query is that a record can be only meta_key - 'lat' or meta_key = 'long' not both because each row only has one meta_key column and can only contain 1 corresponding value, not 2. That would explain why you don't get results when you connect the with an AND; it's impossible.

mappedBy reference an unknown target entity property

I know the answer by @Pascal Thivent has solved the issue. I would like to add a bit more to his answer to others who might be surfing this thread.

If you are like me in the initial days of learning and wrapping your head around the concept of using the @OneToMany annotation with the 'mappedBy' property, it also means that the other side holding the @ManyToOne annotation with the @JoinColumn is the 'owner' of this bi-directional relationship.

Also, mappedBy takes in the instance name (mCustomer in this example) of the Class variable as an input and not the Class-Type (ex:Customer) or the entity name(Ex:customer).

BONUS : Also, look into the orphanRemoval property of @OneToMany annotation. If it is set to true, then if a parent is deleted in a bi-directional relationship, Hibernate automatically deletes it's children.

How do I open workbook programmatically as read-only?

Does this work?

Workbooks.Open Filename:=filepath, ReadOnly:=True

Or, as pointed out in a comment, to keep a reference to the opened workbook:

Dim book As Workbook
Set book = Workbooks.Open(Filename:=filepath, ReadOnly:=True)

How can I test a PDF document if it is PDF/A compliant?

A list of PDF/A validators is on the pdfa.org web site here:

verapdf

A free online PDF/A validator is available here:

http://www.validatepdfa.com/

A report on the accuracy of many of these PDF/A validators is available from PDFLib:

https://www.pdflib.com/fileadmin/pdflib/pdf/pdfa/2009-05-04-Bavaria-report-on-PDFA-validation-accuracy.pdf

Se as well:

https://www.pdflib.com/knowledge-base/pdfa/

What is content-type and datatype in an AJAX request?

See http://api.jquery.com/jQuery.ajax/, there's mention of datatype and contentType there.

They are both used in the request to the server so the server knows what kind of data to receive/send.

ssh : Permission denied (publickey,gssapi-with-mic)

Maybe you should assign the public key to the authorized_keys, the simple way to do this is using ssh-copy-id -i your-pub-key-file user@dest.

gcc makefile error: "No rule to make target ..."

In my case, it was due to me calling the Makefile: MAKEFILE (all caps)

Rails find_or_create_by more than one attribute?

You can do:

User.find_or_create_by(first_name: 'Penélope', last_name: 'Lopez')
User.where(first_name: 'Penélope', last_name: 'Lopez').first_or_create

Or to just initialize:

User.find_or_initialize_by(first_name: 'Penélope', last_name: 'Lopez')
User.where(first_name: 'Penélope', last_name: 'Lopez').first_or_initialize

How to get JSON object from Razor Model object in javascript

After use codevar json = @Html.Raw(Json.Encode(@Model.CollegeInformationlist));

You need use JSON.parse(JSON.stringify(json));

jQuery get the location of an element relative to window

This sounds more like you want a tooltip for the link selected. There are many jQuery tooltips, try out jQuery qTip. It has a lot of options and is easy to change the styles.

Otherwise if you want to do this yourself you can use the jQuery .position(). More info about .position() is on http://api.jquery.com/position/

$("#element").position(); will return the current position of an element relative to the offset parent.

There is also the jQuery .offset(); which will return the position relative to the document.

Create ArrayList from array

You also can do it with stream in Java 8.

 List<Element> elements = Arrays.stream(array).collect(Collectors.toList()); 

How to create a foreign key in phpmyadmin

To be able to create a relation, the table Storage Engine must be InnoDB. You can edit in Operations tab. Storage Engine Configuration

Then, you need to be sure that the id column in your main table has been indexed. It should appear at Index section in Structure tab.

Index list

Finally, you could see the option Relations View in Structure tab. When edditing, you will be able to select the parent column in foreign table to create the relation.

enter image description here

See attachments. I hope this could be useful for anyone.

What is tail call optimization?

TCO (Tail Call Optimization) is the process by which a smart compiler can make a call to a function and take no additional stack space. The only situation in which this happens is if the last instruction executed in a function f is a call to a function g (Note: g can be f). The key here is that f no longer needs stack space - it simply calls g and then returns whatever g would return. In this case the optimization can be made that g just runs and returns whatever value it would have to the thing that called f.

This optimization can make recursive calls take constant stack space, rather than explode.

Example: this factorial function is not TCOptimizable:

def fact(n):
    if n == 0:
        return 1
    return n * fact(n-1)

This function does things besides call another function in its return statement.

This below function is TCOptimizable:

def fact_h(n, acc):
    if n == 0:
        return acc
    return fact_h(n-1, acc*n)

def fact(n):
    return fact_h(n, 1)

This is because the last thing to happen in any of these functions is to call another function.

How to load assemblies in PowerShell?

Make sure you have below features are installed in order

  1. Microsoft System CLR Types for SQL Server
  2. Microsoft SQL Server Shared Management Objects
  3. Microsoft Windows PowerShell Extensions

Also you may need to load

Add-Type -Path "C:\Program Files\Microsoft SQL Server\110\SDK\Assemblies\Microsoft.SqlServer.Smo.dll"
Add-Type -Path "C:\Program Files\Microsoft SQL Server\110\SDK\Assemblies\Microsoft.SqlServer.SqlWmiManagement.dll"

C# - Substring: index and length must refer to a location within the string

You need to find the position of the first /, and then calculate the portion you want:

string url = "www.example.com/aaa/bbb.jpg";
int Idx = url.IndexOf("/");
string yourValue = url.Substring(Idx + 1, url.Length - Idx - 4);

Multiline TextView in Android?

Try to work with EditText by make it unclickable and unfocusable, also you can display a scrollbar and delete the EditText's underbar.
Here is an example:

<EditText
android:id="@+id/my_edit_text"
android:layout_width="match_parent"
android:layout_height="wrap_parent"
android:inputType="textMultiLine"                   <!-- multiline -->
android:clickable="false"                         <!-- unclickable -->
android:focusable="false"                         <!-- unfocusable -->
android:scrollbars="vertical"     <!-- enable scrolling vertically -->
android:background="@android:color/transparent"   <!-- hide the underbar of EditText -->
/>  

Hope this helps :)

How to write a std::string to a UTF-8 text file

As to UTF-8 is multibite characters string and so you get some problems to work and it's a bad idea/ Instead use normal Unicode.

So by my opinion best is use ordinary ASCII char text with some codding set. Need to use Unicode if you use more than 2 sets of different symbols (languages) in single.

It's rather rare case. In most cases enough 2 sets of symbols. For this common case use ASCII chars, not Unicode.

Effect of using multibute chars like UTF-8 you get only China traditional, arabic or some hieroglyphic text. It's very very rare case!!!

I don't think there are many peoples needs that. So never use UTF-8!!! It's avoid strong headache of manipulate such strings.

Python: Binding Socket: "Address already in use"

I think the best way is just to kill the process on that port, by typing in the terminal fuser -k [PORT NUMBER]/tcp, e.g. fuser -k 5001/tcp.

Could not calculate build plan: Plugin org.apache.maven.plugins:maven-resources-plugin:2.6 or one of its dependencies could not be resolved

Step1: Delete all instances of java from you machine

Step2: Delete all the environment variables related to java/jdk/jre

Step3: Check in programm files and program files(X86) folder, there should not be java folder.

Step4: Install java again.

Step5: Go to cmd and type "java -version" Result: it will display the java version which is installed in your machine.

Step6: now delete all the files which are in C:/User/AdminOrUserNameofYourMachine/.m2 folder

Step6: go to cmd and run "mvn -v" Result: It will display the Apache maven version installed on your machine

Step7: Now Rebuild your project.

This worked for me.

Should we @Override an interface's method implementation?

Overriding your own methods inherited from your own classes will typically not break on refactorings using an ide. But if you override a method inherited from a library it is recommended to use it. If you dont, you will often get no error on a later library change, but a well hidden bug.

How to convert JSON object to JavaScript array?

var json_data = {"2013-01-21":1,"2013-01-22":7};
var result = [];

for(var i in json_data)
    result.push([i, json_data [i]]);


var data = new google.visualization.DataTable();
data.addColumn('string', 'Topping');
data.addColumn('number', 'Slices');
data.addRows(result);

http://jsfiddle.net/MV5rj/

How to clear Facebook Sharer cache?

Append a ?v=random_string to the url. If you are using this idea with Facebook share, make sure that the og:url param in the response matches the url you are sharing. This will work with google plus too.

For Facebook, you can also force recrawl by making a post request to https://graph.facebook.com

{id: url,
scrape: true}

insert data from one table to another in mysql

You can use INSERT...SELECT syntax. Note that you can quote '1' directly in the SELECT part.

INSERT INTO mt_magazine_subscription ( 
      magazine_subscription_id, 
      subscription_name, 
      magazine_id, 
      status ) 
SELECT magazine_subscription_id, 
       subscription_name, 
       magazine_id, 
       '1'
FROM tbl_magazine_subscription
ORDER BY magazine_subscription_id ASC 

Hide div by default and show it on click with bootstrap

Try this one:

<button class="button" onclick="$('#target').toggle();">
    Show/Hide
</button>
<div id="target" style="display: none">
    Hide show.....
</div>

Using python PIL to turn a RGB image into a pure black and white image

A simple way to do it using python :

Python
import numpy as np
import imageio

image = imageio.imread(r'[image-path]', as_gray=True)

# getting the threshold value
thresholdValue = np.mean(image)

# getting the dimensions of the image
xDim, yDim = image.shape

# turn the image into a black and white image
for i in range(xDim):
    for j in range(yDim):
        if (image[i][j] > thresholdValue):
            image[i][j] = 255
        else:
            image[i][j] = 0

JavaScript Promises - reject vs. throw

Another important fact is that reject() DOES NOT terminate control flow like a return statement does. In contrast throw does terminate control flow.

Example:

_x000D_
_x000D_
new Promise((resolve, reject) => {_x000D_
  throw "err";_x000D_
  console.log("NEVER REACHED");_x000D_
})_x000D_
.then(() => console.log("RESOLVED"))_x000D_
.catch(() => console.log("REJECTED"));
_x000D_
_x000D_
_x000D_

vs

_x000D_
_x000D_
new Promise((resolve, reject) => {_x000D_
  reject(); // resolve() behaves similarly_x000D_
  console.log("ALWAYS REACHED"); // "REJECTED" will print AFTER this_x000D_
})_x000D_
.then(() => console.log("RESOLVED"))_x000D_
.catch(() => console.log("REJECTED"));
_x000D_
_x000D_
_x000D_

Lock down Microsoft Excel macro

you can set a password to your vba code but this can be quite easily broken up.

you can also create an addin and compile it into a DLL. See here for more information. That's at least the most secure way to protect your code.

Regards,

What are the differences between virtual memory and physical memory?

Softwares run on the OS on a very simple premise - they require memory. The device OS provides it in the form of RAM. The amount of memory required may vary - some softwares need huge memory, some require paltry memory. Most (if not all) users run multiple applications on the OS simultaneously, and given that memory is expensive (and device size is finite), the amount of memory available is always limited. So given that all softwares require a certain amount of RAM, and all of them can be made to run at the same time, OS has to take care of two things:

  1. That the software always runs until user aborts it, i.e. it should not auto-abort because OS has run out of memory.
  2. The above activity, while maintaining a respectable performance for the softwares running.

Now the main question boils down to how the memory is being managed. What exactly governs where in the memory will the data belonging to a given software reside?

Possible solution 1: Let individual softwares specify explicitly the memory address they will use in the device. Suppose Photoshop declares that it will always use memory addresses ranging from 0 to 1023 (imagine the memory as a linear array of bytes, so first byte is at location 0, 1024th byte is at location 1023) - i.e. occupying 1 GB memory. Similarly, VLC declares that it will occupy memory range 1244 to 1876, etc.

Advantages:

  1. Every application is pre-assigned a memory slot, so when it is installed and executed, it just stores its data in that memory area, and everything works fine.

Disadvantages:

  1. This does not scale. Theoretically, an app may require a huge amount of memory when it is doing something really heavy-duty. So to ensure that it never runs out of memory, the memory area allocated to it must always be more than or equal to that amount of memory. What if a software, whose maximal theoretical memory usage is 2 GB (hence requiring 2 GB memory allocation from RAM), is installed in a machine with only 1 GB memory? Should the software just abort on startup, saying that the available RAM is less than 2 GB? Or should it continue, and the moment the memory required exceeds 2 GB, just abort and bail out with the message that not enough memory is available?

  2. It is not possible to prevent memory mangling. There are millions of softwares out there, even if each of them was allotted just 1 kB memory, the total memory required would exceed 16 GB, which is more than most devices offer. How can, then, different softwares be allotted memory slots that do not encroach upon each other's areas? Firstly, there is no centralized software market which can regulate that when a new software is being released, it must assign itself this much memory from this yet unoccupied area, and secondly, even if there were, it is not possible to do it because the no. of softwares is practically infinite (thus requiring infinite memory to accommodate all of them), and the total RAM available on any device is not sufficient to accommodate even a fraction of what is required, thus making inevitable the encroaching of the memory bounds of one software upon that of another. So what happens when Photoshop is assigned memory locations 1 to 1023 and VLC is assigned 1000 to 1676? What if Photoshop stores some data at location 1008, then VLC overwrites that with its own data, and later Photoshop accesses it thinking that it is the same data is had stored there previously? As you can imagine, bad things will happen.

So clearly, as you can see, this idea is rather naive.

Possible solution 2: Let's try another scheme - where OS will do majority of the memory management. Softwares, whenever they require any memory, will just request the OS, and the OS will accommodate accordingly. Say OS ensures that whenever a new process is requesting for memory, it will allocate the memory from the lowest byte address possible (as said earlier, RAM can be imagined as a linear array of bytes, so for a 4 GB RAM, the addresses range for a byte from 0 to 2^32-1) if the process is starting, else if it is a running process requesting the memory, it will allocate from the last memory location where that process still resides. Since the softwares will be emitting addresses without considering what the actual memory address is going to be where that data is stored, OS will have to maintain a mapping, per software, of the address emitted by the software to the actual physical address (Note: that is one of the two reasons we call this concept Virtual Memory. Softwares are not caring about the real memory address where their data are getting stored, they just spit out addresses on the fly, and the OS finds the right place to fit it and find it later if required).

Say the device has just been turned on, OS has just launched, right now there is no other process running (ignoring the OS, which is also a process!), and you decide to launch VLC. So VLC is allocated a part of the RAM from the lowest byte addresses. Good. Now while the video is running, you need to start your browser to view some webpage. Then you need to launch Notepad to scribble some text. And then Eclipse to do some coding.. Pretty soon your memory of 4 GB is all used up, and the RAM looks like this:

                                   enter image description here

Problem 1: Now you cannot start any other process, for all RAM is used up. Thus programs have to be written keeping the maximum memory available in mind (practically even less will be available, as other softwares will be running parallelly as well!). In other words, you cannot run a high-memory consuming app in your ramshackle 1 GB PC.

Okay, so now you decide that you no longer need to keep Eclipse and Chrome open, you close them to free up some memory. The space occupied in RAM by those processes is reclaimed by OS, and it looks like this now:

                                    enter image description here

Suppose that closing these two frees up 700 MB space - (400 + 300) MB. Now you need to launch Opera, which will take up 450 MB space. Well, you do have more than 450 MB space available in total, but...it is not contiguous, it is divided into individual chunks, none of which is big enough to fit 450 MB. So you hit upon a brilliant idea, let's move all the processes below to as much above as possible, which will leave the 700 MB empty space in one chunk at the bottom. This is called compaction. Great, except that...all the processes which are there are running. Moving them will mean moving the address of all their contents (remember, OS maintains a mapping of the memory spat out by the software to the actual memory address. Imagine software had spat out an address of 45 with data 123, and OS had stored it in location 2012 and created an entry in the map, mapping 45 to 2012. If the software is now moved in memory, what used to be at location 2012 will no longer be at 2012, but in a new location, and OS has to update the map accordingly to map 45 to the new address, so that the software can get the expected data (123) when it queries for memory location 45. As far as the software is concerned, all it knows is that address 45 contains the data 123!)! Imagine a process that is referencing a local variable i. By the time it is accessed again, its address has changed, and it won't be able to find it any more. The same will hold for all functions, objects, variables, basically everything has an address, and moving a process will mean changing the address of all of them. Which leads us to:

Problem 2: You cannot move a process. The values of all variables, functions and objects within that process have hardcoded values as spat out by the compiler during compilation, the process depends on them being at the same location during its lifetime, and changing them is expensive. As a result, processes leave behind big "holes" when they exit. This is called External Fragmentation.

Fine. Suppose somehow, by some miraculous manner, you do manage to move the processes up. Now there is 700 MB of free space at the bottom:

                        enter image description here

Opera smoothly fits in at the bottom. Now your RAM looks like this:

                                    enter image description here

Good. Everything is looking fine. However, there is not much space left, and now you need to launch Chrome again, a known memory-hog! It needs lots of memory to start, and you have hardly any left...Except.. you now notice that some of the processes, which were initially occupying large space, now is not needing much space. May be you have stopped your video in VLC, hence it is still occupying some space, but not as much as it required while running a high resolution video. Similarly for Notepad and Photos. Your RAM now looks like this:

                                        enter image description here

Holes, once again! Back to square one! Except, previously, the holes occurred due to processes terminating, now it is due to processes requiring less space than before! And you again have the same problem, the holes combined yield more space than required, but they are scattered around, not much of use in isolation. So you have to move those processes again, an expensive operation, and a very frequent one at that, since processes will frequently reduce in size over their lifetime.

Problem 3: Processes, over their lifetime, may reduce in size, leaving behind unused space, which if needed to be used, will require the expensive operation of moving many processes. This is called Internal Fragmentation.

Fine, so now, your OS does the required thing, moves processes around and start Chrome and after some time, your RAM looks like this:

enter image description here

Cool. Now suppose you again resume watching Avatar in VLC. Its memory requirement will shoot up! But...there is no space left for it to grow, as Notepad is snuggled at its bottom. So, again, all processes has to move below until VLC has found sufficient space!

Problem 4: If processes needs to grow, it will be a very expensive operation

Fine. Now suppose, Photos is being used to load some photos from an external hard disk. Accessing hard-disk takes you from the realm of caches and RAM to that of disk, which is slower by orders of magnitudes. Painfully, irrevocably, transcendentally slower. It is an I/O operation, which means it is not CPU bound (it is rather the exact opposite), which means it does not need to occupy RAM right now. However, it still occupies RAM stubbornly. If you want to launch Firefox in the meantime, you can't, because there is not much memory available, whereas if Photos was taken out of memory for the duration of its I/O bound activity, it would have freed lot of memory, followed by (expensive) compaction, followed by Firefox fitting in.

Problem 5: I/O bound jobs keep on occupying RAM, leading to under-utilization of RAM, which could have been used by CPU bound jobs in the meantime.

So, as we can see, we have so many problems even with the approach of virtual memory.


There are two approaches to tackle these problems - paging and segmentation. Let us discuss paging. In this approach, the virtual address space of a process is mapped to the physical memory in chunks - called pages. A typical page size is 4 kB. The mapping is maintained by something called a page table, given a virtual address, all now we have to do is find out which page the address belong to, then from the page table, find the corresponding location for that page in actual physical memory (known as frame), and given that the offset of the virtual address within the page is same for the page as well as the frame, find out the actual address by adding that offset to the address returned by the page table. For example:

enter image description here

On the left is the virtual address space of a process. Say the virtual address space requires 40 units of memory. If the physical address space (on the right) had 40 units of memory as well, it would have been possible to map all location from the left to a location on the right, and we would have been so happy. But as ill luck would have it, not only does the physical memory have less (24 here) memory units available, it has to be shared between multiple processes as well! Fine, let's see how we make do with it.

When the process starts, say a memory access request for location 35 is made. Here the page size is 8 (each page contains 8 locations, the entire virtual address space of 40 locations thus contains 5 pages). So this location belongs to page no. 4 (35/8). Within this page, this location has an offset of 3 (35%8). So this location can be specified by the tuple (pageIndex, offset) = (4,3). This is just the starting, so no part of the process is stored in the actual physical memory yet. So the page table, which maintains a mapping of the pages on the left to the actual pages on the right (where they are called frames) is currently empty. So OS relinquishes the CPU, lets a device driver access the disk and fetch the page no. 4 for this process (basically a memory chunk from the program on the disk whose addresses range from 32 to 39). When it arrives, OS allocates the page somewhere in the RAM, say first frame itself, and the page table for this process takes note that page 4 maps to frame 0 in the RAM. Now the data is finally there in the physical memory. OS again queries the page table for the tuple (4,3), and this time, page table says that page 4 is already mapped to frame 0 in the RAM. So OS simply goes to the 0th frame in RAM, accesses the data at offset 3 in that frame (Take a moment to understand this. The entire page, which was fetched from disk, is moved to frame. So whatever the offset of an individual memory location in a page was, it will be the same in the frame as well, since within the page/frame, the memory unit still resides at the same place relatively!), and returns the data! Because the data was not found in memory at first query itself, but rather had to be fetched from disk to be loaded into memory, it constitutes a miss.

Fine. Now suppose, a memory access for location 28 is made. It boils down to (3,4). Page table right now has only one entry, mapping page 4 to frame 0. So this is again a miss, the process relinquishes the CPU, device driver fetches the page from disk, process regains control of CPU again, and its page table is updated. Say now the page 3 is mapped to frame 1 in the RAM. So (3,4) becomes (1,4), and the data at that location in RAM is returned. Good. In this way, suppose the next memory access is for location 8, which translates to (1,0). Page 1 is not in memory yet, the same procedure is repeated, and the page is allocated at frame 2 in RAM. Now the RAM-process mapping looks like the picture above. At this point in time, the RAM, which had only 24 units of memory available, is filled up. Suppose the next memory access request for this process is from address 30. It maps to (3,6), and page table says that page 3 is in RAM, and it maps to frame 1. Yay! So the data is fetched from RAM location (1,6), and returned. This constitutes a hit, as data required can be obtained directly from RAM, thus being very fast. Similarly, the next few access requests, say for locations 11, 32, 26, 27 all are hits, i.e. data requested by the process is found directly in the RAM without needing to look elsewhere.

Now suppose a memory access request for location 3 comes. It translates to (0,3), and page table for this process, which currently has 3 entries, for pages 1, 3 and 4 says that this page is not in memory. Like previous cases, it is fetched from disk, however, unlike previous cases, RAM is filled up! So what to do now? Here lies the beauty of virtual memory, a frame from the RAM is evicted! (Various factors govern which frame is to be evicted. It may be LRU based, where the frame which was least recently accessed for a process is to be evicted. It may be first-come-first-evicted basis, where the frame which allocated longest time ago, is evicted, etc.) So some frame is evicted. Say frame 1 (just randomly choosing it). However, that frame is mapped to some page! (Currently, it is mapped by the page table to page 3 of our one and only one process). So that process has to be told this tragic news, that one frame, which unfortunate belongs to you, is to be evicted from RAM to make room for another pages. The process has to ensure that it updates its page table with this information, that is, removing the entry for that page-frame duo, so that the next time a request is made for that page, it right tells the process that this page is no longer in memory, and has to be fetched from disk. Good. So frame 1 is evicted, page 0 is brought in and placed there in the RAM, and the entry for page 3 is removed, and replaced by page 0 mapping to the same frame 1. So now our mapping looks like this (note the colour change in the second frame on the right side):

enter image description here

Saw what just happened? The process had to grow, it needed more space than the available RAM, but unlike our earlier scenario where every process in the RAM had to move to accommodate a growing process, here it happened by just one page replacement! This was made possible by the fact that the memory for a process no longer needs to be contiguous, it can reside at different places in chunks, OS maintains the information as to where they are, and when required, they are appropriately queried. Note: you might be thinking, huh, what if most of the times it is a miss, and the data has to be constantly loaded from disk into memory? Yes, theoretically, it is possible, but most compilers are designed in such a manner that follows locality of reference, i.e. if data from some memory location is used, the next data needed will be located somewhere very close, perhaps from the same page, the page which was just loaded into memory. As a result, the next miss will happen after quite some time, most of the upcoming memory requirements will be met by the page just brought in, or the pages already in memory which were recently used. The exact same principle allows us to evict the least recently used page as well, with the logic that what has not been used in a while, is not likely to be used in a while as well. However, it is not always so, and in exceptional cases, yes, performance may suffer. More about it later.

Solution to Problem 4: Processes can now grow easily, if space problem is faced, all it requires is to do a simple page replacement, without moving any other process.


Solution to Problem 1: A process can access unlimited memory. When more memory than available is needed, the disk is used as backup, the new data required is loaded into memory from the disk, and the least recently used data frame (or page) is moved to disk. This can go on infinitely, and since disk space is cheap and virtually unlimited, it gives an illusion of unlimited memory. Another reason for the name Virtual Memory, it gives you illusion of memory which is not really available!

Cool. Earlier we were facing a problem where even though a process reduces in size, the empty space is difficult to be reclaimed by other processes (because it would require costly compaction). Now it is easy, when a process becomes smaller in size, many of its pages are no longer used, so when other processes need more memory, a simple LRU based eviction automatically evicts those less-used pages from RAM, and replaces them with the new pages from the other processes (and of course updating the page tables of all those processes as well as the original process which now requires less space), all these without any costly compaction operation!

Solution to Problem 3: Whenever processes reduce in size, its frames in RAM will be less used, so a simple LRU based eviction can evict those pages out and replace them with pages required by new processes, thus avoiding Internal Fragmentation without need for compaction.

As for problem 2, take a moment to understand this, the scenario itself is completely removed! There is no need to move a process to accommodate a new process, because now the entire process never needs to fit at once, only certain pages of it need to fit ad hoc, that happens by evicting frames from RAM. Everything happens in units of pages, thus there is no concept of hole now, and hence no question of anything moving! May be 10 pages had to be moved because of this new requirement, there are thousands of pages which are left untouched. Whereas, earlier, all processes (every bit of them) had to be moved!

Solution to Problem 2: To accommodate a new process, data from only less recently used parts of other processes have to be evicted as required, and this happens in fixed size units called pages. Thus there is no possibility of hole or External Fragmentation with this system.

Now when the process needs to do some I/O operation, it can relinquish CPU easily! OS simply evicts all its pages from the RAM (perhaps store it in some cache) while new processes occupy the RAM in the meantime. When the I/O operation is done, OS simply restores those pages to the RAM (of course by replacing the pages from some other processes, may be from the ones which replaced the original process, or may be from some which themselves need to do I/O now, and hence can relinquish the memory!)

Solution to Problem 5: When a process is doing I/O operations, it can easily give up RAM usage, which can be utilized by other processes. This leads to proper utilization of RAM.

And of course, now no process is accessing the RAM directly. Each process is accessing a virtual memory location, which is mapped to a physical RAM address and maintained by the page-table of that process. The mapping is OS-backed, OS lets the process know which frame is empty so that a new page for a process can be fitted there. Since this memory allocation is overseen by the OS itself, it can easily ensure that no process encroaches upon the contents of another process by allocating only empty frames from RAM, or upon encroaching upon the contents of another process in the RAM, communicate to the process to update it page-table.

Solution to Original Problem: There is no possibility of a process accessing the contents of another process, since the entire allocation is managed by the OS itself, and every process runs in its own sandboxed virtual address space.

So paging (among other techniques), in conjunction with virtual memory, is what powers today's softwares running on OS-es! This frees the software developer from worrying about how much memory is available on the user's device, where to store the data, how to prevent other processes from corrupting their software's data, etc. However, it is of course, not full-proof. There are flaws:

  1. Paging is, ultimately, giving user the illusion of infinite memory by using disk as secondary backup. Retrieving data from secondary storage to fit into memory (called page swap, and the event of not finding the desired page in RAM is called page fault) is expensive as it is an IO operation. This slows down the process. Several such page swaps happen in succession, and the process becomes painfully slow. Ever seen your software running fine and dandy, and suddenly it becomes so slow that it nearly hangs, or leaves you with no option that to restart it? Possibly too many page swaps were happening, making it slow (called thrashing).

So coming back to OP,

Why do we need the virtual memory for executing a process? - As the answer explains at length, to give softwares the illusion of the device/OS having infinite memory, so that any software, big or small, can be run, without worrying about memory allocation, or other processes corrupting its data, even when running in parallel. It is a concept, implemented in practice through various techniques, one of which, as described here, is Paging. It may also be Segmentation.

Where does this virtual memory stand when the process (program) from the external hard drive is brought to the main memory (physical memory) for the execution? - Virtual memory doesn't stand anywhere per se, it is an abstraction, always present, when the software/process/program is booted, a new page table is created for it, and it contains the mapping from the addresses spat out by that process to the actual physical address in RAM. Since the addresses spat out by the process are not real addresses, in one sense, they are, actually, what you can say, the virtual memory.

Who takes care of the virtual memory and what is the size of the virtual memory? - It is taken care of by, in tandem, the OS and the software. Imagine a function in your code (which eventually compiled and made into the executable that spawned the process) which contains a local variable - an int i. When the code executes, i gets a memory address within the stack of the function. That function is itself stored as an object somewhere else. These addresses are compiler generated (the compiler which compiled your code into the executable) - virtual addresses. When executed, i has to reside somewhere in actual physical address for duration of that function at least (unless it is a static variable!), so OS maps the compiler generated virtual address of i into an actual physical address, so that whenever, within that function, some code requires the value of i, that process can query the OS for that virtual address, and OS in turn can query the physical a

Stateless vs Stateful

Stateless means there is no memory of the past. Every transaction is performed as if it were being done for the very first time.

Stateful means that there is memory of the past. Previous transactions are remembered and may affect the current transaction.

Stateless:

// The state is derived by what is passed into the function

function int addOne(int number)
{
    return number + 1;
}

Stateful:

// The state is maintained by the function

private int _number = 0; //initially zero

function int addOne()
{
   _number++;
   return _number;
}

Refer from: https://softwareengineering.stackexchange.com/questions/101337/whats-the-difference-between-stateful-and-stateless

How to set MimeBodyPart ContentType to "text/html"?

Call MimeMessage.saveChanges() on the enclosing message, which will update the headers by cascading down the MIME structure into a call to MimeBodyPart.updateHeaders() on your body part. It's this updateHeaders call that transfers the content type from the DataHandler to the part's MIME Content-Type header.

When you set the content of a MimeBodyPart, JavaMail internally (and not obviously) creates a DataHandler object wrapping the object you passed in. The part's Content-Type header is not updated immediately.

There's no straightforward way to do it in your test program, since you don't have a containing MimeMessage and MimeBodyPart.updateHeaders() isn't public.


Here's a working example that illuminates expected and unexpected outputs:

public class MailTest {

  public static void main( String[] args ) throws Exception {
    Session mailSession = Session.getInstance( new Properties() );
    Transport transport = mailSession.getTransport();

    String text = "Hello, World";
    String html = "<h1>" + text + "</h1>";

    MimeMessage message = new MimeMessage( mailSession );
    Multipart multipart = new MimeMultipart( "alternative" );

    MimeBodyPart textPart = new MimeBodyPart();
    textPart.setText( text, "utf-8" );

    MimeBodyPart htmlPart = new MimeBodyPart();
    htmlPart.setContent( html, "text/html; charset=utf-8" );

    multipart.addBodyPart( textPart );
    multipart.addBodyPart( htmlPart );
    message.setContent( multipart );

    // Unexpected output.
    System.out.println( "HTML = text/html : " + htmlPart.isMimeType( "text/html" ) );
    System.out.println( "HTML Content Type: " + htmlPart.getContentType() );

    // Required magic (violates principle of least astonishment).
    message.saveChanges();

    // Output now correct.    
    System.out.println( "TEXT = text/plain: " + textPart.isMimeType( "text/plain" ) );
    System.out.println( "HTML = text/html : " + htmlPart.isMimeType( "text/html" ) );
    System.out.println( "HTML Content Type: " + htmlPart.getContentType() );
    System.out.println( "HTML Data Handler: " + htmlPart.getDataHandler().getContentType() );
  }
}

How to install plugin for Eclipse from .zip

The accepted answer from Konstantin worked, but there were a few additional steps. After restarting Eclipse, you still have to go into software updates, find your newly available software, check the box(es) for it, and click the "install" button. Then it'll prompt you to restart again and only then will you see your new views or functionality.

Additionally, you can check the "Error Log" view for any problems with your new plugin that eclipse is complaining about.

How do I do an initial push to a remote repository with Git?

You can try this:

on Server:

adding new group to /etc/group like (example)

mygroup:1001:michael,nir

create new git repository:

mkdir /srv/git
cd /srv/git
mkdir project_dir
cd project_dir
git --bare init (initial git repository )
chgrp -R mygroup objects/ refs/ (change owner of directory )
chmod -R g+w objects/ refs/ (give permission write)

on Client:

mkdir my_project
cd my_project
touch .gitignore
git init
git add .
git commit -m "Initial commit"
git remote add origin [email protected]:/path/to/my_project.git
git push origin master

(Thanks Josh Lindsey for client side)

after Client, do on Server this commands:

cd /srv/git/project_dir
chmod -R g+w objects/ refs/

If got this error after git pull:

There is no tracking information for the current branch. Please specify which branch you want to merge with. See git-pull(1) for details

git pull <remote> <branch>
If you wish to set tracking information for this branch you can do so with:

git branch --set-upstream new origin/<branch>

try:

git push -u origin master

It will help.

What is the best way to return different types of ResponseEntity in Spring MVC or Spring-Boot

I recommend using Spring's @ControllerAdvice to handle errors. Read this guide for a good introduction, starting at the section named "Spring Boot Error Handling". For an in-depth discussion, there's an article in the Spring.io blog that was updated on April, 2018.

A brief summary on how this works:

  • Your controller method should only return ResponseEntity<Success>. It will not be responsible for returning error or exception responses.
  • You will implement a class that handles exceptions for all controllers. This class will be annotated with @ControllerAdvice
  • This controller advice class will contain methods annotated with @ExceptionHandler
  • Each exception handler method will be configured to handle one or more exception types. These methods are where you specify the response type for errors
  • For your example, you would declare (in the controller advice class) an exception handler method for the validation error. The return type would be ResponseEntity<Error>

With this approach, you only need to implement your controller exception handling in one place for all endpoints in your API. It also makes it easy for your API to have a uniform exception response structure across all endpoints. This simplifies exception handling for your clients.

Adding an assets folder in Android Studio

According to new Gradle based build system. We have to put assets under main folder.

Or simply right click on your project and create it like

File > New > folder > assets Folder

Using the slash character in Git branch name

Sometimes that problem occurs if you already have a branch with the base name.

I tried this:

git checkout -b features/aName origin/features/aName

Unfortunately, I already had a branch named features, and I got the exception of the question asker.

Removing the branch features resolved the problem, the above command worked.

JAVA_HOME should point to a JDK not a JRE

Under System Variables add below

JAVA_HOME = C:\Program Files\Java\jdk1.8.0_201

JDK_HOME = %JAVA_HOME%\bin

M2_HOME = C:\apache-maven-3.6.0

MAVEN_BIN = %M2_HOME%\bin

MAVEN_HOME = %M2_HOME%

Under path Add these

%M2_HOME%

%JDK_HOME%

C++ - struct vs. class

You could prove to yourself that there is no other difference by trying to define a function in a struct. I remember even my college professor who was teaching about structs and classes in C++ was surprised to learn this (after being corrected by a student). I believe it, though. It was kind of amusing. The professor kept saying what the differences were and the student kept saying "actually you can do that in a struct too". Finally the prof. asked "OK, what is the difference" and the student informed him that the only difference was the default accessibility of members.

A quick Google search suggests that POD stands for "Plain Old Data".

Codeigniter - multiple database connections

It works fine for me...

This is default database :

$db['default'] = array(
    'dsn'   => '',
    'hostname' => 'localhost',
    'username' => 'root',
    'password' => '',
    'database' => 'mydatabase',
    'dbdriver' => 'mysqli',
    'dbprefix' => '',
    'pconnect' => TRUE,
    'db_debug' => (ENVIRONMENT !== 'production'),
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
);

Add another database at the bottom of database.php file

$db['second'] = array(
    'dsn'   => '',
    'hostname' => 'localhost',
    'username' => 'root',
    'password' => '',
    'database' => 'mysecond',
    'dbdriver' => 'mysqli',
    'dbprefix' => '',
    'pconnect' => TRUE,
    'db_debug' => (ENVIRONMENT !== 'production'),
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
);

In autoload.php config file

$autoload['libraries'] = array('database', 'email', 'session');

The default database is worked fine by autoload the database library but second database load and connect by using constructor in model and controller...

<?php
    class Seconddb_model extends CI_Model {
        function __construct(){
            parent::__construct();
            //load our second db and put in $db2
            $this->db2 = $this->load->database('second', TRUE);
        }

        public function getsecondUsers(){
            $query = $this->db2->get('members');
            return $query->result(); 
        }

    }
?>

How to use filesaver.js

https://github.com/koffsyrup/FileSaver.js#examples

Saving text(All Browsers)

saveTextAs("Hi,This,is,a,CSV,File", "test.csv");
saveTextAs("<div>Hello, world!</div>", "test.html");

Saving text(HTML 5)

var blob = new Blob(["Hello, world!"], {type: "text/plain;charset=utf-8"});
saveAs(blob, "hello world.txt");

null check in jsf expression language

Use empty (it checks both nullness and emptiness) and group the nested ternary expression by parentheses (EL is in certain implementations/versions namely somewhat problematic with nested ternary expressions). Thus, so:

styleClass="#{empty obj.validationErrorMap ? ' ' :  
 (obj.validationErrorMap.contains('key') ? 'highlight_field' : 'highlight_row')}"

If still in vain (I would then check JBoss EL configs), use the "normal" EL approach:

styleClass="#{empty obj.validationErrorMap ? ' ' :  
 (obj.validationErrorMap['key'] ne null ? 'highlight_field' : 'highlight_row')}"

Update: as per the comments, the Map turns out to actually be a List (please work on your naming conventions). To check if a List contains an item the "normal" EL way, use JSTL fn:contains (although not explicitly documented, it works for List as well).

styleClass="#{empty obj.validationErrorMap ? ' ' :  
 (fn:contains(obj.validationErrorMap, 'key') ? 'highlight_field' : 'highlight_row')}"

How to print a list of symbols exported from a dynamic library

Use nm -a your.dylib

It will print all the symbols including globals

How to make a select with array contains value clause in psql

Try

SELECT * FROM table WHERE arr @> ARRAY['s']::varchar[]

jquery dialog save cancel button styling

Here is how to add custom classes in jQuery UI Dialog (Version 1.8+):

$('#foo').dialog({
    'buttons' : {
        'cancel' : {
            priority: 'secondary', class: 'foo bar baz', click: function() {
                ...
            },
        },
    }
}); 

Python IndentationError: unexpected indent

You can't mix tab and spaces for identation. Best practice is to convert all tabs to spaces.

How to fix this? Well just delete all the spaces/tabs before each line and convert them uniformly either to tabs OR spaces, but don't mix. Best solution: enable in your Editor the option to convert automagically any tabs to spaces.

Also be aware that your actual problem may lie in the lines before this block, and python throws the error here, because of a leading invalid indentation which doesn't match the following identations!

PHP How to fix Notice: Undefined variable:

I would guess your query isn't running as expected and you are getting to the return line with undefined variables.

Also, the way you are doing the variable assignment, you would be overwriting the same variable with each loop iteration, so you wouldn't return the entire result set.

Finally, it seems odd to return a numerically-keyed result set instead of an associatively-keyed one. Consider naming only the fields needed in the SELECT and keeping the key assignments. So something like this:

Function ShowDataPatient($idURL){
       $query =" select * from cmu_list_insurance,cmu_home,cmu_patient where cmu_home.home_id = (select home_id from cmu_patient where patient_hn like '%$idURL%')
                 AND cmu_patient.patient_hn like '%$idURL%'
                 AND cmu_list_insurance.patient_id like (select patient_id from cmu_patient where patient_hn like '%$idURL%') ";

   $result = pg_query($query) or die('Query failed: ' . pg_last_error());

   $return = array();
   while ($row = pg_fetch_array($result)){
       $return[] = $row;
   }          

   return $return;
}

You might also consider opening a question about how to improve your query, is it is pretty heinous as it stands now.

python how to pad numpy array with zeros

NumPy 1.7.0 (when numpy.pad was added) is pretty old now (it was released in 2013) so even though the question asked for a way without using that function I thought it could be useful to know how that could be achieved using numpy.pad.

It's actually pretty simple:

>>> import numpy as np
>>> a = np.array([[ 1.,  1.,  1.,  1.,  1.],
...               [ 1.,  1.,  1.,  1.,  1.],
...               [ 1.,  1.,  1.,  1.,  1.]])
>>> np.pad(a, [(0, 1), (0, 1)], mode='constant')
array([[ 1.,  1.,  1.,  1.,  1.,  0.],
       [ 1.,  1.,  1.,  1.,  1.,  0.],
       [ 1.,  1.,  1.,  1.,  1.,  0.],
       [ 0.,  0.,  0.,  0.,  0.,  0.]])

In this case I used that 0 is the default value for mode='constant'. But it could also be specified by passing it in explicitly:

>>> np.pad(a, [(0, 1), (0, 1)], mode='constant', constant_values=0)
array([[ 1.,  1.,  1.,  1.,  1.,  0.],
       [ 1.,  1.,  1.,  1.,  1.,  0.],
       [ 1.,  1.,  1.,  1.,  1.,  0.],
       [ 0.,  0.,  0.,  0.,  0.,  0.]])

Just in case the second argument ([(0, 1), (0, 1)]) seems confusing: Each list item (in this case tuple) corresponds to a dimension and item therein represents the padding before (first element) and after (second element). So:

[(0, 1), (0, 1)]
         ^^^^^^------ padding for second dimension
 ^^^^^^-------------- padding for first dimension

  ^------------------ no padding at the beginning of the first axis
     ^--------------- pad with one "value" at the end of the first axis.

In this case the padding for the first and second axis are identical, so one could also just pass in the 2-tuple:

>>> np.pad(a, (0, 1), mode='constant')
array([[ 1.,  1.,  1.,  1.,  1.,  0.],
       [ 1.,  1.,  1.,  1.,  1.,  0.],
       [ 1.,  1.,  1.,  1.,  1.,  0.],
       [ 0.,  0.,  0.,  0.,  0.,  0.]])

In case the padding before and after is identical one could even omit the tuple (not applicable in this case though):

>>> np.pad(a, 1, mode='constant')
array([[ 0.,  0.,  0.,  0.,  0.,  0.,  0.],
       [ 0.,  1.,  1.,  1.,  1.,  1.,  0.],
       [ 0.,  1.,  1.,  1.,  1.,  1.,  0.],
       [ 0.,  1.,  1.,  1.,  1.,  1.,  0.],
       [ 0.,  0.,  0.,  0.,  0.,  0.,  0.]])

Or if the padding before and after is identical but different for the axis, you could also omit the second argument in the inner tuples:

>>> np.pad(a, [(1, ), (2, )], mode='constant')
array([[ 0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.],
       [ 0.,  0.,  1.,  1.,  1.,  1.,  1.,  0.,  0.],
       [ 0.,  0.,  1.,  1.,  1.,  1.,  1.,  0.,  0.],
       [ 0.,  0.,  1.,  1.,  1.,  1.,  1.,  0.,  0.],
       [ 0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.]])

However I tend to prefer to always use the explicit one, because it's just to easy to make mistakes (when NumPys expectations differ from your intentions):

>>> np.pad(a, [1, 2], mode='constant')
array([[ 0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.],
       [ 0.,  1.,  1.,  1.,  1.,  1.,  0.,  0.],
       [ 0.,  1.,  1.,  1.,  1.,  1.,  0.,  0.],
       [ 0.,  1.,  1.,  1.,  1.,  1.,  0.,  0.],
       [ 0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.],
       [ 0.,  0.,  0.,  0.,  0.,  0.,  0.,  0.]])

Here NumPy thinks you wanted to pad all axis with 1 element before and 2 elements after each axis! Even if you intended it to pad with 1 element in axis 1 and 2 elements for axis 2.

I used lists of tuples for the padding, note that this is just "my convention", you could also use lists of lists or tuples of tuples, or even tuples of arrays. NumPy just checks the length of the argument (or if it doesn't have a length) and the length of each item (or if it has a length)!

Spring boot - configure EntityManager

Hmmm you can find lot of examples for configuring spring framework. Anyways here is a sample

@Configuration
@Import({PersistenceConfig.class})
@ComponentScan(basePackageClasses = { 
    ServiceMarker.class,
    RepositoryMarker.class }
)
public class AppConfig {

}

PersistenceConfig

@Configuration
@PropertySource(value = { "classpath:database/jdbc.properties" })
@EnableTransactionManagement
public class PersistenceConfig {

    private static final String PROPERTY_NAME_HIBERNATE_DIALECT = "hibernate.dialect";
    private static final String PROPERTY_NAME_HIBERNATE_MAX_FETCH_DEPTH = "hibernate.max_fetch_depth";
    private static final String PROPERTY_NAME_HIBERNATE_JDBC_FETCH_SIZE = "hibernate.jdbc.fetch_size";
    private static final String PROPERTY_NAME_HIBERNATE_JDBC_BATCH_SIZE = "hibernate.jdbc.batch_size";
    private static final String PROPERTY_NAME_HIBERNATE_SHOW_SQL = "hibernate.show_sql";
    private static final String[] ENTITYMANAGER_PACKAGES_TO_SCAN = {"a.b.c.entities", "a.b.c.converters"};

    @Autowired
    private Environment env;

     @Bean(destroyMethod = "close")
     public DataSource dataSource() {
         BasicDataSource dataSource = new BasicDataSource();
         dataSource.setDriverClassName(env.getProperty("jdbc.driverClassName"));
         dataSource.setUrl(env.getProperty("jdbc.url"));
         dataSource.setUsername(env.getProperty("jdbc.username"));
         dataSource.setPassword(env.getProperty("jdbc.password"));
         return dataSource;
     }

     @Bean
     public JpaTransactionManager jpaTransactionManager() {
         JpaTransactionManager transactionManager = new JpaTransactionManager();
         transactionManager.setEntityManagerFactory(entityManagerFactoryBean().getObject());
         return transactionManager;
     }

    private HibernateJpaVendorAdapter vendorAdaptor() {
         HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
         vendorAdapter.setShowSql(true);
         return vendorAdapter;
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactoryBean() {

         LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
         entityManagerFactoryBean.setJpaVendorAdapter(vendorAdaptor());
         entityManagerFactoryBean.setDataSource(dataSource());
         entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistenceProvider.class);
         entityManagerFactoryBean.setPackagesToScan(ENTITYMANAGER_PACKAGES_TO_SCAN);             
         entityManagerFactoryBean.setJpaProperties(jpaHibernateProperties());

         return entityManagerFactoryBean;
     }

     private Properties jpaHibernateProperties() {

         Properties properties = new Properties();

         properties.put(PROPERTY_NAME_HIBERNATE_MAX_FETCH_DEPTH, env.getProperty(PROPERTY_NAME_HIBERNATE_MAX_FETCH_DEPTH));
         properties.put(PROPERTY_NAME_HIBERNATE_JDBC_FETCH_SIZE, env.getProperty(PROPERTY_NAME_HIBERNATE_JDBC_FETCH_SIZE));
         properties.put(PROPERTY_NAME_HIBERNATE_JDBC_BATCH_SIZE, env.getProperty(PROPERTY_NAME_HIBERNATE_JDBC_BATCH_SIZE));
         properties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, env.getProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));

         properties.put(AvailableSettings.SCHEMA_GEN_DATABASE_ACTION, "none");
         properties.put(AvailableSettings.USE_CLASS_ENHANCER, "false");      
         return properties;       
     }

}

Main

public static void main(String[] args) { 
    try (GenericApplicationContext springContext = new AnnotationConfigApplicationContext(AppConfig.class)) {
        MyService myService = springContext.getBean(MyServiceImpl.class);
        try {
            myService.handleProcess(fromDate, toDate);
        } catch (Exception e) {
            logger.error("Exception occurs", e);
            myService.handleException(fromDate, toDate, e);
        }
    } catch (Exception e) {
        logger.error("Exception occurs in loading Spring context: ", e);
    }
}

MyService

@Service
public class MyServiceImpl implements MyService {

    @Inject
    private MyDao myDao;

    @Override
    public void handleProcess(String fromDate, String toDate) {
        List<Student> myList = myDao.select(fromDate, toDate);
    }
}

MyDaoImpl

@Repository
@Transactional
public class MyDaoImpl implements MyDao {

    @PersistenceContext
    private EntityManager entityManager;

    public Student select(String fromDate, String toDate){

        TypedQuery<Student> query = entityManager.createNamedQuery("Student.findByKey", Student.class);
        query.setParameter("fromDate", fromDate);
        query.setParameter("toDate", toDate);
        List<Student> list = query.getResultList();
        return CollectionUtils.isEmpty(list) ? null : list;
    }

}

Assuming maven project: Properties file should be in src/main/resources/database folder

jdbc.properties file

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=your db url
jdbc.username=your Username
jdbc.password=Your password

hibernate.max_fetch_depth = 3
hibernate.jdbc.fetch_size = 50
hibernate.jdbc.batch_size = 10
hibernate.show_sql = true

ServiceMarker and RepositoryMarker are just empty interfaces in your service or repository impl package.

Let's say you have package name a.b.c.service.impl. MyServiceImpl is in this package and so is ServiceMarker.

public interface ServiceMarker {

}

Same for repository marker. Let's say you have a.b.c.repository.impl or a.b.c.dao.impl package name. Then MyDaoImpl is in this this package and also Repositorymarker

public interface RepositoryMarker {

}

a.b.c.entities.Student

//dummy class and dummy query
@Entity
@NamedQueries({
@NamedQuery(name="Student.findByKey", query="select s from Student s where s.fromDate=:fromDate" and s.toDate = :toDate)
})
public class Student implements Serializable {

    private LocalDateTime fromDate;
    private LocalDateTime toDate;

    //getters setters

}

a.b.c.converters

@Converter(autoApply = true)
public class LocalDateTimeConverter implements AttributeConverter<LocalDateTime, Timestamp> {

    @Override
    public Timestamp convertToDatabaseColumn(LocalDateTime dateTime) {

        if (dateTime == null) {
            return null;
        }
        return Timestamp.valueOf(dateTime);
    }

    @Override
    public LocalDateTime convertToEntityAttribute(Timestamp timestamp) {

        if (timestamp == null) {
            return null;
        }    
        return timestamp.toLocalDateTime();
    }
}

pom.xml

<properties>
    <java-version>1.8</java-version>
    <org.springframework-version>4.2.1.RELEASE</org.springframework-version>
    <hibernate-entitymanager.version>5.0.2.Final</hibernate-entitymanager.version>
    <commons-dbcp2.version>2.1.1</commons-dbcp2.version>
    <mysql-connector-java.version>5.1.36</mysql-connector-java.version>
     <junit.version>4.12</junit.version> 
</properties>

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>${junit.version}</version>
        <scope>test</scope>
    </dependency>

    <!-- Spring -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <dependency>
        <groupId>javax.inject</groupId>
        <artifactId>javax.inject</artifactId>
        <version>1</version>
        <scope>compile</scope>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>${org.springframework-version}</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
        <version>${org.springframework-version}</version>
    </dependency>

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>${hibernate-entitymanager.version}</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql-connector-java.version}</version>
    </dependency>

    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-dbcp2</artifactId>
        <version>${commons-dbcp2.version}</version>
    </dependency>
</dependencies>

<build>
     <finalName>${project.artifactId}</finalName>
     <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.3</version>
            <configuration>
                <source>${java-version}</source>
                <target>${java-version}</target>
                <compilerArgument>-Xlint:all</compilerArgument>
                <showWarnings>true</showWarnings>
                <showDeprecation>true</showDeprecation>
            </configuration>
        </plugin>
     </plugins>
</build>

Hope it helps. Thanks

What is the purpose of nameof?

I find that nameof increases the readability of very long and complex SQL statements in my applications. It makes the variables stand out of that sea of strings and eliminates your job of figuring out where the variables are used in your SQL statements.

public bool IsFooAFoo(string foo, string bar)
{
    var aVeryLongAndComplexQuery = $@"SELECT yada, yada
    -- long query in here
    WHERE fooColumn = @{nameof(foo)}
    AND barColumn = @{nameof(bar)}
    -- long query here";


    SqlParameter[] parameters = {
        new SqlParameter(nameof(foo), SqlDBType.VarChar, 10){ Value = foo },
        new SqlParameter(nameof(bar), SqlDBType.VarChar, 10){ Value = bar },
    }
}

Override standard close (X) button in a Windows Form

You can override OnFormClosing to do this. Just be careful you don't do anything too unexpected, as clicking the 'X' to close is a well understood behavior.

protected override void OnFormClosing(FormClosingEventArgs e)
{
    base.OnFormClosing(e);

    if (e.CloseReason == CloseReason.WindowsShutDown) return;

    // Confirm user wants to close
    switch (MessageBox.Show(this, "Are you sure you want to close?", "Closing", MessageBoxButtons.YesNo))
    {
    case DialogResult.No:
        e.Cancel = true;
        break;
    default:
        break;
    }        
}

How do I change the root directory of an Apache server?

In RedHat 7.0: /etc/httpd/conf/httpd.conf

ValueError: all the input arrays must have same number of dimensions

(n,) and (n,1) are not the same shape. Try casting the vector to an array by using the [:, None] notation:

n_lists = np.append(n_list_converted, n_last[:, None], axis=1)

Alternatively, when extracting n_last you can use

n_last = n_list_converted[:, -1:]

to get a (20, 1) array.

Mercurial undo last commit

after you have pulled and updated your workspace do a thg and right click on the change set you want to get rid of and then click modify history -> strip, it will remove the change set and you will point to default tip.

Send parameter to Bootstrap modal window?

There is a better solution than the accepted answer, specifically using data-* attributes. Setting the id to 1 will cause you issues if any other element on the page has id=1. Instead, you can do:

<button class="btn btn-primary" data-toggle="modal" data-target="#yourModalID" data-yourparameter="whateverYouWant">Load</button>

<script>
$('#yourModalID').on('show.bs.modal', function(e) {
  var yourparameter = e.relatedTarget.dataset.yourparameter;
  // Do some stuff w/ it.
});
</script>

How to detect if javascript files are loaded?

I don't have a reference for it handy, but script tags are processed in order, and so if you put your $(document).ready(function1) in a script tag after the script tags that define function1, etc., you should be good to go.

<script type='text/javascript' src='...'></script>
<script type='text/javascript' src='...'></script>
<script type='text/javascript'>
$(document).ready(function1);
</script>

Of course, another approach would be to ensure that you're using only one script tag, in total, by combining files as part of your build process. (Unless you're loading the other ones from a CDN somewhere.) That will also help improve the perceived speed of your page.

EDIT: Just realized that I didn't actually answer your question: I don't think there's a cross-browser event that's fired, no. There is if you work hard enough, see below. You can test for symbols and use setTimeout to reschedule:

<script type='text/javascript'>
function fireWhenReady() {
    if (typeof function1 != 'undefined') {
        function1();
    }
    else {
        setTimeout(fireWhenReady, 100);
    }
}
$(document).ready(fireWhenReady);
</script>

...but you shouldn't have to do that if you get your script tag order correct.


Update: You can get load notifications for script elements you add to the page dynamically if you like. To get broad browser support, you have to do two different things, but as a combined technique this works:

function loadScript(path, callback) {

    var done = false;
    var scr = document.createElement('script');

    scr.onload = handleLoad;
    scr.onreadystatechange = handleReadyStateChange;
    scr.onerror = handleError;
    scr.src = path;
    document.body.appendChild(scr);

    function handleLoad() {
        if (!done) {
            done = true;
            callback(path, "ok");
        }
    }

    function handleReadyStateChange() {
        var state;

        if (!done) {
            state = scr.readyState;
            if (state === "complete") {
                handleLoad();
            }
        }
    }
    function handleError() {
        if (!done) {
            done = true;
            callback(path, "error");
        }
    }
}

In my experience, error notification (onerror) is not 100% cross-browser reliable. Also note that some browsers will do both mechanisms, hence the done variable to avoid duplicate notifications.

DIV table colspan: how?

Trying to think in tableless design does not mean that you can not use tables :)

It is only that you can think of it that tabular data can be presented in a table, and that other elements (mostly div's) are used to create the layout of the page.

So I should say that you have to read some information on styling with div-elements, or use this page as a good example page!

Good luck ;)

How to use random in BATCH script?

%RANDOM% gives you a random number between 0 and 32767.

Using an expression like SET /A test=%RANDOM% * 100 / 32768 + 1, you can change the range to anything you like (here the range is [1…100] instead of [0…32767]).

Java Synchronized list

Yes, it will work fine as you have synchronized the list . I would suggest you to use CopyOnWriteArrayList.

CopyOnWriteArrayList<String> cpList=new CopyOnWriteArrayList<String>(new ArrayList<String>());

    void remove(String item)
    {
         do something; (doesn't work on the list)
                 cpList..remove(item);
    }

CSS fixed width in a span

The <span> tag will need to be set to display:block as it is an inline element and will ignore width.

so:

<style type="text/css"> span { width: 50px; display: block; } </style>

and then:

<li><span>&nbsp;</span>something</li>
<li><span>AND</span>something else</li>

Check line for unprintable characters while reading text file

Just found out that with the Java NIO (java.nio.file.*) you can easily write:

List<String> lines=Files.readAllLines(Paths.get("/tmp/test.csv"), StandardCharsets.UTF_8);
for(String line:lines){
  System.out.println(line);
}

instead of dealing with FileInputStreams and BufferedReaders...

How to create global variables accessible in all views using Express / Node.JS?

After having a chance to study the Express 3 API Reference a bit more I discovered what I was looking for. Specifically the entries for app.locals and then a bit farther down res.locals held the answers I needed.

I discovered for myself that the function app.locals takes an object and stores all of its properties as global variables scoped to the application. These globals are passed as local variables to each view. The function res.locals, however, is scoped to the request and thus, response local variables are accessible only to the view(s) rendered during that particular request/response.

So for my case in my app.js what I did was add:

app.locals({
    site: {
        title: 'ExpressBootstrapEJS',
        description: 'A boilerplate for a simple web application with a Node.JS and Express backend, with an EJS template with using Twitter Bootstrap.'
    },
    author: {
        name: 'Cory Gross',
        contact: '[email protected]'
    }
});

Then all of these variables are accessible in my views as site.title, site.description, author.name, author.contact.

I could also define local variables for each response to a request with res.locals, or simply pass variables like the page's title in as the optionsparameter in the render call.

EDIT: This method will not allow you to use these locals in your middleware. I actually did run into this as Pickels suggests in the comment below. In this case you will need to create a middleware function as such in his alternative (and appreciated) answer. Your middleware function will need to add them to res.locals for each response and then call next. This middleware function will need to be placed above any other middleware which needs to use these locals.

EDIT: Another difference between declaring locals via app.locals and res.locals is that with app.locals the variables are set a single time and persist throughout the life of the application. When you set locals with res.locals in your middleware, these are set everytime you get a request. You should basically prefer setting globals via app.locals unless the value depends on the request req variable passed into the middleware. If the value doesn't change then it will be more efficient for it to be set just once in app.locals.

URL to load resources from the classpath in Java

I think this is worth its own answer - if you're using Spring, you already have this with

Resource firstResource =
    context.getResource("http://www.google.fi/");
Resource anotherResource =
    context.getResource("classpath:some/resource/path/myTemplate.txt");

Like explained in the spring documentation and pointed out in the comments by skaffman.

How can I save a base64-encoded image to disk?

I think you are converting the data a bit more than you need to. Once you create the buffer with the proper encoding, you just need to write the buffer to the file.

var base64Data = req.rawBody.replace(/^data:image\/png;base64,/, "");

require("fs").writeFile("out.png", base64Data, 'base64', function(err) {
  console.log(err);
});

new Buffer(..., 'base64') will convert the input string to a Buffer, which is just an array of bytes, by interpreting the input as a base64 encoded string. Then you can just write that byte array to the file.

Update

As mentioned in the comments, req.rawBody is no longer a thing. If you are using express/connect then you should use the bodyParser() middleware and use req.body, and if you are doing this using standard Node then you need to aggregate the incoming data event Buffer objects and do this image data parsing in the end callback.

Does C# support multiple inheritance?

I recently somehow got to the same mindset, inheriting two classes into a class and ended up on this page (even though i know better) and would like to keep reference to the solution i found perfect in this scenario, without enforcing implementation of interfaces

My solution to this problem would be splitting up your data into classes that make sense:

public class PersonAddressSuper
{
    public PersonBase Person { get; set; }
    public PersonAddress Address { get; set; }

    public class PersonBase
    {
        public int ID { get; set; }
        public string Name { get; set; }
    }
    public class PersonAddress
    {
        public string StreetAddress { get; set; }
        public string City { get; set; }
    }
}

Later on in your code, you could use it like this:

Include Both Parts, Base & Address

PersonAddressSuper PersonSuper = new PersonAddressSuper();
PersonSuper.PersonAddress.StreetAddress = "PigBenis Road 16";

Base Only:

PersonAddressSuper.PersonBase PersonBase = new PersonAddressSuper.PersonBase();
PersonBase.Name = "Joe Shmoe";

Address Only:

PersonAddressSuper.PersonAddress PersonAddress = new PersonAddressSuper.PersonAddress();
PersonAddress.StreetAddress = "PigBenis Road 16";