Getter and Setter

Question

I m not a PHP developer  so I m wondering if in PHP is more popular to use explicit getter setters  in a pure OOP style  with private fields  the way I like    class MyClass       private  firstField      private  secondField       public function getFirstField             return  this- gt firstField            public function setFirstField  x             this- gt firstField    x            public function getSecondField             return  this- gt secondField            public function setSecondField  x             this- gt secondField    x            or just public fields   class MyClass       public  firstField      public  secondField      Thanks

User · Answer

There are many ways to create sourcecode in a netbeans-convention  This is nice  It makes thinks such easyer     FALSE  Just use the traditionel  specially if you are not sure which one of the properties should be encapsuled and which one not  I know  it is a boi     pla    code  but for debugging-works and many other thinks it is the better  clear way  Dont spend to much time with thousend of arts how to make simple getters and setters  You cannot implement too some design patterns like the demeter-rule and so on  if you use magics  In specific situation you can use magic calls or for small  fast and clear solutions  Sure you could make solutions for design-patters in this way too  but why to make you live more difficult

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This post is not specifically about   get and   set but rather   call which is the same idea except for method calling  As a rule  I stay away from any type of magic methods that allow for overloading for reasons outlined in the comments and posts HOWEVER  I recently ran into a 3rd-party API that I use which uses a SERVICE and a SUB-SERVICE  example   http   3rdparty api com service APIService doActionOne amp apikey 12341234   The important part of this is that this API has everything the same except the sub-action  in this case doActionOne  The idea is that the developer  myself and others using this class  could call the sub-service by name as opposed to something like    myClass- gt doAction array  service   gt  doActionOne   args   gt  args      I could do instead     myClass- gt doActionOne  args     To hardcode this would just be a lot of duplication  this example very loosely resembles the code    public function doActionOne  array                 this- gt args          array           name                 FUNCTION             this- gt response      this- gt executeCoreCall  APIService   name            public function doActionTwo  array                 this- gt args          array           name                 FUNCTION             this- gt response      this- gt executeCoreCall  APIService   name            public function doActionThree  array                 this- gt args          array           name                 FUNCTION             this- gt response      this- gt executeCoreCall  APIService   name            protected function executeCoreCall  service                 cURL   new  cURL            return  cURL- gt   http   3rdparty api com service    service   amp apikey    this- gt api   amp   http build query  this- gt args                       - gt getResponse            But with the magic method of   call   I am able to access all services with dynamic methods   public function   call  name   arguments                 this- gt args          arguments           this- gt response      this- gt executeCoreCall  APIService   name                return  this          The benefit of this dynamic calling for the return of data is that if the vendor adds another sub-service  I do not have to add another method into the class or create an extended class  etc  I am not sure if this is useful to anyone  but I figured I would show an example where   set    get    call  etc  may be an option for consideration since the primary function is the return of data     EDIT   Coincidentally  I saw this a few days after posting which outlines exactly my scenario  It is not the API I was referring to but the application of the methods is identical   Am I using api correctly

User · Answer

Generally speaking  the first way is more popular overall because those with prior programming knowledge can easily transition to PHP and get work done in an object-oriented fashion  The first way is more universal  My advice would be to stick with what is tried and true across many languages  Then  when and if you use another language  you ll be ready to get something accomplished  instead of spending time reinventing the wheel

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I made an experiment using the magic method   call  Not sure if I should post it  because of all the  DO NOT USE MAGIC METHODS  warnings in the other answers and comments  but i ll leave it here   just in case someone find it useful     public function   call   name    arguments        action    substr   name  0  4        varName   substr   name  4        if  isset  this- gt   varName             if   action      get    return  this- gt   varName           if   action      set     this- gt   varName      arguments 0             Just add that method above in your class  now you can type   class MyClass      private foo    bar       private bom    bim                     public function   call                        C   new MyClass        as getter  C- gt get foo       return  bar   C- gt get bom       return  bim      as setter  C- gt set foo  abc       set  abc  as new value of foo  C- gt set bom  zam       set  zam  as new value of bom       This way you can get set everything in your class if it exist so  if you need it for only a few specific elements  you could use a  whitelist  as filter     Example   private  callWhiteList   array       foo    gt   foo        fee    gt   fee                  public function   call   name    arguments        action    substr   name  0  4        varName    this- gt callWhiteList substr   name  4         if   is null  varName   amp  amp  isset  this- gt   varName             if   action      get    return  this- gt   varName           if   action      set     this- gt   varName      arguments 0             Now you can only get set  foo  and  fee   You can also use that  whitelist  to assign custom names to access to your vars  For example   private  callWhiteList   array       myfoo    gt   foo        zim    gt   bom                   With that list you can now type   class MyClass      private foo    bar       private bom    bim                     private  callWhiteList   array               public function   call                        C   new MyClass        as getter  C- gt get myfoo       return  bar   C- gt get zim       return  bim      as setter  C- gt set myfoo  abc       set  abc  as new value of foo  C- gt set zim  zam       set  zam  as new value of bom           That s all     Doc    call   is triggered when invoking inaccessible methods in an object context

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Update  Don t use this answer since this is very dumb code that I found while I learn  Just use plain getter and setter  it s much better     I usually using that variable name as function name  and add optional parameter to that function so when that optional parameter is filled by caller  then set it to the property and return  this object  chaining  and then when that optional parameter not specified by caller  i just return the property to the caller   My example   class Model        private  propOne       private  propTwo        public function propOne  propVal                        if   propVal                         return  this- gt propOne              else                  this- gt propOne    propVal                return  this                           public function propTwo  propVal                        if   propVal                         return  this- gt propTwo              else                  this- gt propTwo    propVal                return  this

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After reading the other advices  I m inclined to say that   As a GENERIC rule  you will not always define setters for ALL properties  specially  internal  ones  semaphores  internal flags      Read-only properties will not have setters  obviously  so some properties will only have getters  that s where   get   comes to shrink the code    define a   get    magical global getters  for all those properties which are alike  group them in arrays so   they ll share common characteristics  monetary values will may come up properly formatted  dates in an specific layout  ISO  US  Intl    etc  the code itself can verify that only existing  amp  allowed properties are being read using this magical method  whenever you need to create a new similar property  just declare it and add its name to the proper array and it s done  That s way FASTER than defining a new getter  perhaps with some lines of code REPEATED again and again all over the class code     Yes  we could write a private method to do that  also  but then again  we ll have MANY methods declared    memory  that end up calling another  always the same  method  Why just not write a SINGLE method to rule them all      yep  pun absolutely intended       Magic setters can also respond ONLY to specific properties  so all date type properties can be screened against invalid values in one method alone  If date type properties were listed in an array  their setters can be defined easily  Just an example  of course  there are way too many situations   About readability    Well    That s another debate  I don t like to be bound to the uses of an IDE  in fact  I don t use them  they tend to tell me  and force me  how to write    and I have my likes about coding  beauty    I tend to be consistent about naming  so using ctags and a couple of other aids is sufficient to me    Anyway  once all this magic setters and  getters are done  I write the other setters that are too specific or  special  to be generalized in a   set   method  And that covers all I need about getting and setting properties  Of course  there s not always a common ground  or there are such a few properties that is not worth the trouble of coding a magical method  and then there s still the old good traditional setter getter pair   Programming languages are just that  human artificial languages  So  each of them has its own intonation or accent  syntax and flavor  so I won t pretend to write a Ruby or Python code using the same  accent  than Java or C   nor I would write a JavaScript or PHP to resemble Perl or SQL    Use them the way they re meant to be used

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If you preffer to use the   call function  you can use this method  It works with   GET     this- gt property   SET     this- gt property  value  GET     this- gt getProperty   SET     this- gt setProperty  value    kalsdas  public function   call  name   arguments           Getting and setting with  this- gt property  optional        if  property exists get class  this    name                 Always set the value if a parameter is passed         if  count  arguments     1                   set                 this- gt  name    arguments 0             else if  count  arguments   gt  1                throw new  Exception  Setter for  name only accepts one parameter                          Always return the value  Even on the set          return  this- gt  name               If it doesn t chech if its a normal old type setter ot getter       Getting and setting with  this- gt getProperty  optional         Getting and setting with  this- gt setProperty  optional        prefix   substr  name  0  3        property   strtolower  name 3     substr  name  4       switch   prefix            case  get               return  this- gt  property              break          case  set                 Always set the value if a parameter is passed             if  count  arguments     1                    throw new  Exception  Setter for  name requires exactly one parameter                                this- gt  property    arguments 0                 Always return the value  Even on the set              return  this- gt  name          default              throw new  Exception  Property  name doesn t exist                 break

User · Answer

You can use php magic methods   get and   set    lt  php class MyClass     private  firstField    private  secondField     public function   get  property        if  property exists  this   property           return  this- gt  property               public function   set  property   value        if  property exists  this   property            this- gt  property    value             return  this          gt

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class MyClass       private  firstField      private  secondField      private  thirdField       public function   get   name             if  method exists   this    method      get    ucfirst   name                      return  this- gt  method            else             throw new Exception   Can  t get property      name               public function   set   name    value             if  method exists   this    method      set    ucfirst   name                      return  this- gt  method   value            else             throw new Exception   Can  t set property      name               public function   isset   name                 return method exists   this    get    ucfirst   name                      method exists   this    set    ucfirst   name                  public function getFirstField             return  this- gt firstField             protected function setFirstField  x             this- gt firstField    x             private function getSecondField             return  this- gt secondField            obj   new MyClass     echo  obj- gt firstField     works  obj- gt firstField    value      works  echo  obj- gt getFirstField       works  obj- gt setFirstField   value        not works  method is protected  echo  obj- gt secondField     works echo  obj- gt getSecondField       not works  method is private   obj- gt secondField    value      not works  setter not exists  echo  obj- gt thirdField     not works  property not exists  isset   obj- gt firstField       returns true isset   obj- gt secondField       returns true isset   obj- gt thirdField       returns false   Ready

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Encapsulation is important in any OO language  popularity has nothing to do with it  In dynamically typed languages  like PHP  it is especially useful because there is little ways to ensure a property is of a specific type without using setters   In PHP  this works   class Foo      public  bar     should be an integer    foo   new Foo   foo- gt bar    string     In Java  it doesn t   class Foo      public int bar    Foo myFoo   new Foo    myFoo bar    string      error   Using magic methods    get and   set  also works  but only when accessing a property that has lower visibility than the current scope can access  It can easily give you headaches when trying to debug  if it is not used properly

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Validating   Formatting Deriving Values Setters let you to validate data and getters let you format or derive data  Objects allow you to encapsulate data and its validation and formatting code into a neat package that encourages DRY  For example  consider the following simple class that contains a birth date  class BirthDate        private  birth date       public function getBirthDate  format  Y-m-d               format  birth date                birth date               return  birth date             public function setBirthDate  birth date                                 if  birth date is not valid  throw an exception                        this- gt birth date    birth date             public function getAge               calculate age             return  age             public function getDaysUntilBirthday               calculate days until birth days         return  days           You ll want to validate that the value being set is  A valid date Not in the future  And you don t want to do this validation all over your application  or over multiple applications for that matter   Instead  it s easier to make the member variable protected or private  in order to make the setter the only access point  and to validate in the setter because then you ll know that the object contains a valid birth date no matter which part of the application the object came from and if you want to add more validation then you can add it in a single place  You might want to add multiple formatters that operate on the same member variable i e  getAge   and getDaysUntilBirthday   and you might want to enforce a configurable format in getBirthDate   depending on locale  Therefore I prefer consistently accessing values via getters as opposed to mixing  date- gt getAge   with  date- gt birth date  getters and setters are also useful when you extend objects  For example  suppose your application needed to allow 150  year birth dates in some places but not in others  One way to solve the problem without repeating any code would be to extend the BirthDate object and put the additional validation in the setter  class LivingBirthDate extends BirthDate        public function setBirthDate  birth date              if  birth date is greater than 150 years throw an exception           else pass to parent s setter         return parent  setBirthDate  birth date

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Well  PHP does have magic methods   get    set    isset  amp    unset  which is always a start  Alas proper  get it   OO properties is more than magic methods  The main problem with PHP s implementation is that magic methods are called for all inaccessible properties  Which means you have to Repeat Yourself  eg  by calling property exists    in the magic methods when determining if name is actually a property of your object  And you can t really solve this general problem with a base class unless all your classes inherit from ie  ClassWithProperties  since PHP lacks multiple inheritance   In contrast  Python new style classes gives you property    which lets you explicitly define all your properties  C  has special syntax    http   en wikipedia org wiki Property  programming

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Why use getters and setters    Scalability  It s easier refactor a getter than search all the var assignments in a project code  Debugging  You can put breakpoints at setters and getters  Cleaner  Magic functions are not good solution for writting less  your IDE will not suggest the code  Better use templates for fast-writting getters

User · Answer

In addition to the already great and respected answers in here  I would like to expand on PHP having no setters getters   PHP does not have getter and setter syntax  It provides subclassed or magic methods to allow  hooking  and overriding the property lookup process  as pointed out by Dave   Magic allows us lazy programmers to do more with less code at a time at which we are actively engaged in a project and know it intimately  but usually at the expense of readability   Performance Every unnecessary function  that results from forcing a getter setter-like code-architecture in PHP  involves its own memory stack-frame upon invocation and is wasting CPU cycles    Readability  The codebase incurs bloating code-lines  which impacts code-navigation as more LOC mean more scrolling    Preference  Personally  as my rule of thumb  I take the failure of static code analysis  as a sign to avoid going down the magical road as long as obvious long-term benefits elude me at that time   Fallacies   A common argument is readability  For instance that  someobject- gt width is easier to read than  someobject- gt width    However unlike a planet s circumference or width  which can be assumed to be  static  an object s instance such as  someobject  which requires a width function  likely takes a measurement of the object s instance width  Therefore readability increases mainly because of assertive naming-schemes and not by hiding the function away that outputs a given property-value     get     set uses    pre-validation and pre-sanitation of property values strings e g     some  mathsobj1- gt generatelatex  multi line text  mathsobj1- gt latexoutput  with lots of variables for  mathsobj1- gt generatelatex   some reason     In this case generatelatex would adhere to a naming scheme of actionname   methodname special  obvious cases   dnastringobj- gt homeobox  one rememberable parameter - gt gattaca- gt findrelated    dnastringobj- gt homeobox  one rememberable parameter - gt gttccaatttga- gt findrelated      Note  PHP chose not to implement getter setter syntax  I am not claiming that getters setter are generally bad

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Google already published a guide on optimization of PHP and the conclusion was   No getter and setter Optimizing PHP  And no  you must not use magic methods   For PHP  Magic Method are evil  Why    They are hard to debug  There is a negative performance impact  They require writing more code    PHP is not Java  C    or C   PHP is different and plays with different roles

[php] Getter and Setter?

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