In general, creating a Groovy class in a wiki page is not really recommended and usually it's nicer to create code in Java and make it available to XWiki pages through Script Services.

However there might be a few cases when it's handy to create a Groovy class in a wiki page and reuse it from several other wiki pages.

In XWiki Syntax 2.0+

• Create a page, for example Groovy.HelloWorldClass containing:
  Information

  This page must have been saved by a user with programming rights to be executed.

  {{groovy}}
  class HelloWorld
  {
    String say()
    {
      return "Hello World"
    }
  }
  {{/groovy}}

• Use this Groovy class from another wiki page, say from Main.HelloWorldFromGroovy:
  Information

  This page must have been saved by a user with programming rights to be executed.

  {{include document="Groovy.HelloWorldClass"/}}
  
  {{groovy}}
  println new HelloWorld().say()
  {{/groovy}}

Now when you view Main.HelloWorldFromVelocity you'll see: Hello World

In XWiki Syntax 1.0

You'll need to use the XWiki.parseGroovyFromPage API method. This method allow you to instantiate a Groovy class from both Velocity and Groovy scripts.

• Create a new page, for example Groovy.HelloWorldClass containing:
  Information

  • This page must have been saved by a user with programming rights to be executed.
  • When creating a page that has to be accessed via parseGroovyFromString make sure you do not have opening and closing groovy identifiers.

  /* Groovy Class #* */
  
  class HelloWorldClass
  {
    def xwiki
    def context
  
    void setObjects(xwiki, context)
    {
      setXWiki(xwiki)
      setContext(context)
    }
  
    void setXWiki(xwiki)
    {
      this.xwiki = xwiki
    }
  
    void setContext(context)
    {
      this.context = context
    }
  
    String say()
    {
      return "Hello World"
    }
  }
  
  /* *# */

  Information

  • Notice the trick of putting a Velocity comment in the Groovy comment so that the code is not parsed by Velocity.
  • As you can see, we can get and store the XWiki and Context objects in the class to be able to use them; their use is not illustrated in this tutorial though.

Instantiate and use your class from Velocity

• Create a new page, for example Main.HelloWorldFromVelocity containing:

  #set($groovyObject = $xwiki.parseGroovyFromPage("Groovy.HelloWorldClass"))
  $groovyObject.setObjects($xwiki, $context)
  $groovyObject.say()

• See the result. Feeling groovy ?

Instantiate and use your class from Groovy

• Create a new page, for example Main.HelloWorldFromGroovy containing:
  Information

  This page must have been saved by a user with programming rights to be executed.

  <%
  groovyObject = xwiki.parseGroovyFromPage("Groovy.HelloWorldClass")
  groovyObject.setObjects(xwiki, context)
  print groovyObject.say()
  %>