Package groovy.util

Class DelegatingScript

java.lang.Object
groovy.lang.GroovyObjectSupport
groovy.lang.Script
groovy.util.DelegatingScript
All Implemented Interfaces:
GroovyObject
public abstract class DelegatingScript extends Script
Script that performs method invocations and property access like Closure does.

DelegatingScript is a convenient basis for loading a custom-defined DSL as a Script, then execute it. The following sample code illustrates how to do it: 

 class MyDSL {
     public void foo(int x, int y, Closure z) { ... }
     public void setBar(String a) { ... }
 }

 CompilerConfiguration cc = new CompilerConfiguration();
 cc.setScriptBaseClass(DelegatingScript.class.getName());
 GroovyShell sh = new GroovyShell(cl,new Binding(),cc);
 DelegatingScript script = (DelegatingScript)sh.parse(new File("my.dsl"))
 script.setDelegate(new MyDSL());
 script.run();

my.dsl can look like this: 

 foo(1,2) {
     ....
 }
 bar = ...;

DelegatingScript does this by delegating property access and method invocation to the delegate object.

More formally speaking, given the following script: 

 a = 1;
 b(2);

Using DelegatingScript as the base class, the code will run as: 

 delegate.a = 1;
 delegate.b(2);
... whereas in plain Script, this will be run as: 
 binding.setProperty("a",1);
 ((Closure)binding.getProperty("b")).call(2);

  • Constructor Details

    • DelegatingScript

      protected DelegatingScript()
      Creates a delegating script with an empty binding.

    • DelegatingScript

      protected DelegatingScript(Binding binding)
      Creates a delegating script using the supplied binding.
      Parameters:
      binding - the binding to use for the script

  • Method Details

    • setDelegate

      public void setDelegate(Object delegate)
      Sets the delegation target.

    • invokeMethod

      public Object invokeMethod(String name, Object args)
      Delegates method invocation before falling back to normal script dispatch.
      Specified by:
      invokeMethod in interface GroovyObject
      Overrides:
      invokeMethod in class Script
      Parameters:
      name - the method name
      args - the invocation arguments
      Returns:
      the invocation result

    • getProperty

      public Object getProperty(String property)
      Resolves properties against the delegate before the script binding.
      Specified by:
      getProperty in interface GroovyObject
      Overrides:
      getProperty in class Script
      Parameters:
      property - the property name
      Returns:
      the property value

    • setProperty

      public void setProperty(String property, Object newValue)
      Sets a property on the delegate before falling back to the script binding.
      Specified by:
      setProperty in interface GroovyObject
      Overrides:
      setProperty in class Script
      Parameters:
      property - the property name
      newValue - the new property value

    • getDelegate

      public Object getDelegate()
      Returns the current delegation target.
      Returns:
      the delegate object