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Groovy example source code file (ThreadInterrupt.groovy)

This example Groovy source code file (ThreadInterrupt.groovy) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Groovy tags/keywords

annotation, class, class, groovyasttransformationclass, groovyasttransformationclass, interruptedexception, interruptedexception, target, target, threadinterrupt

The Groovy ThreadInterrupt.groovy source code

/*
 * Copyright 2008-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package groovy.transform;

import java.lang.annotation.ElementType
import java.lang.annotation.Retention
import java.lang.annotation.RetentionPolicy
import java.lang.annotation.Target
import org.codehaus.groovy.transform.GroovyASTTransformationClass


/**
 * Allows "interrupt-safe" executions of scripts by adding Thread.currentThread().isInterrupted()
 * checks on loops (for, while, do), the first statement of closures, and the first statement of methods.
 * <br/>
 * <br/>
 * 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.
 * <br/>
 * <br/>
 * Annotating anything in a script will cause for loops, while loops, methods, and closures to make an
 * isInterruptedCheck and throw a InterruptedException if the check yields true. The annotation by default
 * will apply 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. 
 * <br/>
 * <br/>
 * 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:
 * <br/>
 * <pre>
 * <code>@groovy.transform.ThreadInterrupt
 * def scriptMethod() {
 *     4.times {
 *         println 'executing script method...'
 *     }
 * }
 *
 * class MyClass {
 *
 *   def myMethod() {
 *       for (i in (1..10)) {
 *           println 'executing method...'
 *       }
 *   }
 * }
 *
 * scriptMethod()
 * new MyClass().myMethod()
 * </pre>
 * <br/>
 * Which results in the following code being generated. Notice the checks and exceptions:
 * <br/>
 * <pre>
 * public class script1290627909406 extends groovy.lang.Script {
 *
 *     public java.lang.Object scriptMethod() {
 *         if (java.lang.Thread.currentThread().isInterrupted()) {
 *             throw new java.lang.InterruptedException('Execution Interrupted')
 *         }
 *         4.times({
 *             if (java.lang.Thread.currentThread().isInterrupted()) {
 *                 throw new java.lang.InterruptedException('Execution Interrupted')
 *             }
 *             this.println('executing script method...')
 *         })
 *     }
 * }
 * public class MyClass extends java.lang.Object {
 *
 *     public java.lang.Object myMethod() {
 *         if (java.lang.Thread.currentThread().isInterrupted()) {
 *             throw new java.lang.InterruptedException('Execution Interrupted')
 *         }
 *         for (java.lang.Object i : (1..10)) {
 *             if (java.lang.Thread.currentThread().isInterrupted()) {
 *                 throw new java.lang.InterruptedException('Execution Interrupted')
 *             }
 *             this.println('executing method...')
 *         }
 *     }
 * }
 *
 * this.scriptMethod()
 * new MyClass().myMethod()
 * <br/>
 *
 * @see groovy.transform.TimedInterrupt
 * @see groovy.transform.ConditionalInterrupt
 *
 * @author Cedric Champeau
 * @author Hamlet D'Arcy
 *
 * @since 1.8.0
 */
@java.lang.annotation.Documented
@Retention(RetentionPolicy.SOURCE)
@Target([ ElementType.METHOD, ElementType.TYPE])
@GroovyASTTransformationClass(["org.codehaus.groovy.transform.ThreadInterruptibleASTTransformation"])
public @interface ThreadInterrupt {
    /**
     * 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.
     * @return
     */
    boolean applyToAllClasses() default true;
    /**
     * 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.  
     * @return
     */
    boolean checkOnMethodStart() default true;

    Class thrown() default InterruptedException;
}

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