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Groovy example source code file (Field.java)

This example Groovy source code file (Field.java) 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, field, field, groovyasttransformationclass, groovyasttransformationclass, target, target

The Groovy Field.java 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 org.codehaus.groovy.transform.GroovyASTTransformationClass;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Variable annotation used for changing the scope of a variable within a script from
 * being within the run method of the script to being at the class level for the script.
 * <p>
 * The annotated variable will become a private field of the script class.
 * The type of the field will be the same as the type of the variable. Example usage:
 * <pre>
 * {@code @Field} List awe = [1, 2, 3]
 * def awesum() { awe.sum() }
 * assert awesum() == 6
 * </pre>
 * In this example, without the annotation, variable <code>awe would be
 * a local script variable (technically speaking it will be a local variable within
 * the <code>run method of the script class). Such a local variable would
 * not be visible inside the <code>awesum method. With the annotation,
 * <code>awe becomes a private List field in the script class and is
 * visible within the <code>awesum method.
 *
 * @author Paul King
 * @since 1.8.0
 */
@java.lang.annotation.Documented
@Retention(RetentionPolicy.SOURCE)
@Target({ElementType.LOCAL_VARIABLE})
@GroovyASTTransformationClass("org.codehaus.groovy.transform.FieldASTTransformation")
public @interface Field {
}

Other Groovy examples (source code examples)

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