Including a groovy script in another groovy

Question

I have read how to simply import a groovy file in another groovy script  I want to define common functions in one groovy file and call those functions from other groovy files    I understand this would be using Groovy like a scripting language i e  I dont need classes objects  I am trying to something like dsl that can be done in groovy  All variables will be asserted from Java and I want to execute groovy script in a shell    Is this possible at all   Can someone provide some example

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For late-comers  it appears that groovy now support the  load file-path command which simply redirects input from the given file  so it is now trivial to include library scripts   It works as input to the groovysh  amp  as a line in a loaded file  groovy 000 gt   load file1 groovy  file1 groovy can contain   load path to another file invoke fn from file

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Groovy doesn t have an import keyword like typical scripting languages that will do a literal include of another file s contents  alluded to here  Does groovy provide an include mechanism     Because of its object class oriented nature  you have to  play games  to make things like this work  One possibility is to make all your utility functions static  since you said they don t use objects  and then perform a static import in the context of your executing shell  Then you can call these methods like  global functions    Another possibility would be using a Binding object  http   groovy codehaus org api groovy lang Binding html  while creating your Shell and binding all the functions you want to the methods  the downside here would be having to enumerate all methods in the binding but you could perhaps use reflection    Yet another solution would be to override methodMissing      in the delegate object assigned to your shell which allows you to basically do dynamic dispatch using a map or whatever method you d like     Several of these methods are demonstrated here  http   www nextinstruction com blog 2012 01 08 creating-dsls-with-groovy    Let me know if you want to see an example of a particular technique

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Groovy can import other groovy classes exactly like Java does  Just be sure the extension of the library file is  groovy           cat lib Lib groovy     package lib     class Lib          static saySomething     println  something           def sum a b    a b                cat app gvy     import lib Lib     Lib saySomething        println new Lib   sum 37 5         groovy app     something     42

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Here s a complete example of including one script within another  Just run the Testmain groovy file Explanatory comments included because I m nice like that     Testutils groovy     This is the  include file     Testmain groovy will load it as an implicit class    Each method in here will become a method on the implicit class  def myUtilityMethod String msg        println  myUtilityMethod running with    msg       Testmain groovy     Run this file     evaluate implicitly creates a class based on the filename specified evaluate new File    Testutils groovy       Safer to use  def  here as Groovy seems fussy about whether the filename  and therefore implicit class name  has a capital first letter def tu   new Testutils   tu myUtilityMethod  hello world

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I think that the best choice is to organize utility things in form of groovy classes  add them to classpath and let main script refer to them via import keyword   Example   scripts DbUtils groovy  class DbUtils      def save something           scripts script1 groovy   import DbUtils def dbUtils   new DbUtils   def something    foobar  dbUtils save something    running script   cd scripts groovy -cp   script1 groovy

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A combination of  grahamparks and  snowindy answers with a couple of modifications is what worked for my Groovy scripts running on Tomcat   Utils groovy  class Utils       def doSth             MyScript groovy      import Utils -- gt  This import does not work  The class is not even defined at this time    Class groovyClass   new GroovyClassLoader getClass   getClassLoader    parseClass new File  full path to Utils groovy        Otherwise it assumes current dir is  CATALINA HOME def foo   groovyClass newInstance        def  solves compile time errors   foo doSth       Actually works

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As of Groovy 2 2 it is possible to declare a base script class with the new  BaseScript AST transform annotation   Example   file MainScript groovy   abstract class MainScript extends Script       def meaningOfLife   42     file test groovy   import groovy transform BaseScript  BaseScript MainScript mainScript  println   meaningOfLife    works as expected

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After some investigation I have come to the conclusion that the following approach seems the best   some subpackage Util groovy   GrabResolver name    nexus   root    https   local-nexus-server 8443 repository maven-public   m2Compatible   true   Grab  com google errorprone error prone annotations 2 1 3    Grab  com google guava guava 23 0    GrabExclude  com google errorprone error prone annotations    import com google common base Strings  class Util       void msg int a  String b  Map c            println  Message printed by msg method inside Util groovy          println  Print 5 asterisks using the Guava dependency   Strings repeat      5            println  Arguments are a  a  b  b  c  c            example groovy     usr bin env groovy Class clazz   new GroovyClassLoader   parseClass    new File getClass   protectionDomain codeSource location path  parent  some subpackage Util groovy  as File  GroovyObject u   clazz newInstance   u msg 1   b    a   b   c   d      In order to run the example groovy script  add it to your system path and type from any directory   example groovy   The script prints   Message printed by msg method inside Util groovy Print 5 asterisks using the Guava dependency       Arguments are a 1  b b  c  a b  c d    The above example was tested in the following environment  Groovy Version  2 4 13 JVM  1 8 0 151 Vendor  Oracle Corporation OS  Linux  The example demonstrates the following    How to use a Util class inside a groovy script  A Util class calling the Guava third party library by including it as a Grape dependency   Grab  com google guava guava 23 0     The Util class can reside in a subdirectory  Passing arguments to a method within the Util class    Additional comments suggestions    Always use a groovy class instead of groovy script for reusable functionality within your groovy scripts  The above example uses the Util class defined in the Util groovy file  Using groovy scripts for reusable functionality is problematic  For example  if using a groovy script then the Util class would have to be instantiated at the bottom of the script with new Util    but most importantly it would have to be placed in a file named anything but Util groovy  Refer to Scripts versus classes for more details about the differences between groovy scripts and groovy classes  In the above example I use the path    new File getClass   protectionDomain codeSource location path  parent  some subpackage Util groovy  instead of  some subpackage Util groovy   This will guarantee that the Util groovy file will always be found in relation to the groovy script s location  example groovy  and not the current working directory  For example  using  some subpackage Util groovy  would result in searching at WORK DIR some subpackage Util groovy  Follow the Java class naming convention to name your groovy scripts  I personally prefer a small deviation where the scripts start with a lower letter instead of a capital one  For example  myScript groovy is a script name  and MyClass groovy is a class name  Naming my-script groovy will result in runtime errors in certain scenarios because the resulting class will not have a valid Java class name  In the JVM world in general the relevant functionality is named JSR 223  Scripting for the Java  In groovy in particular the functionality is named Groovy integration mechanisms  In fact  the same approach can be used in order to call any JVM language from within Groovy or Java  Some notable examples of such JVM languages are Groovy  Java  Scala  JRuby  and JavaScript  Rhino

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Another way to do this is to define the functions in a groovy class and parse and add the file to the classpath at runtime   File sourceFile   new File  path to file groovy    Class groovyClass   new GroovyClassLoader getClass   getClassLoader    parseClass sourceFile   GroovyObject myObject    GroovyObject  groovyClass newInstance

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The way that I do this is with GroovyShell   GroovyShell shell   new GroovyShell   def Util   shell parse new File  Util groovy    def data   Util fetchData

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How about treat the external script as a Java class  Based on this article  https   www jmdawson net blog 2014 08 18 using-functions-from-one-groovy-script-in-another   getThing groovy  The external script  def getThingList         return   thing   thin2   thing3       printThing groovy  The main script  thing   new getThing       new the class which represents the external script println thing getThingList     Result    groovy printThing groovy  thing  thin2  thing3

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evaluate new File     tools Tools groovy      Put that at the top of your script   That will bring in the contents of a groovy file  just replace the file name between the double quotes with your groovy script    I do this with a class surprisingly called  Tools groovy

[groovy] Including a groovy script in another groovy

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