Groovy Documentation

## groovy.transform
[Groovy] Annotation Type ConditionalInterrupt

    java.lang.Object
      groovy.transform.ConditionalInterrupt

    @Retention(RetentionPolicy.SOURCE)
    @Target([ ElementType.METHOD, ElementType.TYPE])
    @GroovyASTTransformationClass(["org.codehaus.groovy.transform.ConditionalInterruptibleASTTransformation"])
    @interface ConditionalInterrupt

Allows "interrupt-safe" executions of scripts by adding a custom check for interruption on loops (for, while, do), the first statement of closures, and the first statement of methods.
This is especially useful when executing foreign scripts that you do not have control over. Inject this transformation into a script that you need to interrupt based on some custom criteria.
Annotating anything in a script will cause for loops, while loops, methods, and closures to make a check against the specified closure. If the closure yields true (according to GroovyTruth), then the script will throw an InterruptedException. The annotation by default applies to any classes defined in the script as well. Annotated a class will cause (by default) all classes in the entire file ('Compilation Unit') to be enhanced. You can fine tune what is enhanced using the annotation parameters.
Extensive usage examples can be found in the unit test for this class. A smaller example is presented here. The following is sample usage of the annotation:

     @ConditionalInterrupt({ counter++> 10})
     import groovy.transform.ConditionalInterrupt

     counter = 0
     def scriptMethod() {
          4.times {
              println 'executing script method...'
          }
     }

     scriptMethod()

Which results in the following code being generated. Notice the checks and exceptions:

     public class script1291741477073 extends groovy.lang.Script {

         Object counter = 0

         public java.lang.Object run() {
             counter = 0
         }

         public java.lang.Object scriptMethod() {
             if (this.conditionalTransform$condition()) {
                 throw new java.lang.InterruptedException('Execution interrupted. The following condition failed: { counter++> 10}')
             }
             4.times({
                 if (this.conditionalTransform$condition()) {
                     throw new java.lang.InterruptedException('Execution interrupted. The following condition failed: { counter++> 10}')
                 }
                 this.println('executing script method...')
             })
         }

         private java.lang.Object conditionalTransform$condition() {
             counter++ > 10
         }
     }

Note that when you're annotating scripts, the variable scoping semantics are unchanged. Therefore, you must be careful about the variable scope you're using. Make sure that variables you reference in the closure parameter are in scope during script execution. The following example will throw a MissingPropertyException because counter is not in scope for a class:

     import groovy.transform.ConditionalInterrupt

     def counter = 0
     @ConditionalInterrupt({ counter++> 10})
     class MyClass {
         def myMethod() {
             4.times {
                 println 'executing script method...'
             }
         }
     }

     new MyClass().myMethod()

Authors:
  Cedric Champeau
  Hamlet D'Arcy

See Also:
  TimedInterrupt
  ThreadInterrupt

Since:
  1.8.0

Method Summary
`boolean` | `applyToAllClasses()` By default, annotating anything in a source file ('Compilation Unit') will trigger this transformation for all classes and scripts in that file.
`boolean` | `checkOnMethodStart()` By default an isInterrupted check is added to the start of all user-defined methods.
`java.lang.Class` | `thrown()` Sets the type of exception which is thrown.
`java.lang.Class` | `value()` Condition should be set as a closure expression.

Methods inherited from class java.lang.Object
java.lang.Object#wait(long), java.lang.Object#wait(long, int), java.lang.Object#wait(), java.lang.Object#equals(java.lang.Object), java.lang.Object#toString(), java.lang.Object#hashCode(), java.lang.Object#getClass(), java.lang.Object#notify(), java.lang.Object#notifyAll()

Method Detail

### applyToAllClasses

    boolean applyToAllClasses()

  By default, annotating anything in a source file ('Compilation Unit') will trigger this transformation for all classes and scripts in that file. If you add the Annotation to an import statement, then all scripts and Classes will be enhanced. If you want to change this behavior then set applyToAllClasses to false. If you annotate a type then only that type will be augmented, not other types or the surrounding script. If you annotate a script, then any enclosed types will not be augmented. @default true
  Returns:

### checkOnMethodStart

    boolean checkOnMethodStart()

  By default an isInterrupted check is added to the start of all user-defined methods. To turn this off simply set this parameter to false. @default true
  Returns:

### thrown

    java.lang.Class thrown()

  Sets the type of exception which is thrown. @default InterruptedException
  Returns:

### value

    java.lang.Class value()

  Condition should be set as a closure expression.
  Returns:

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