Struts example source code file (Action.java)

This example Struts source code file (Action.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 - Struts tags/keywords

action, annotation, default_value, default_value, exceptionmapping, interceptorref, interceptorref, result, string, string, target, target

The Struts Action.java source code

/*
 * $Id: Action.java 768826 2009-04-26 22:58:17Z musachy $
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.struts2.convention.annotation;

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

/**
 * <!-- START SNIPPET: javadoc -->
 * <p>
 * This annotation can be used to control the URL that maps to
 * a specific method in an Action class. By default, the method
 * that is invoked is the execute method of the action and the
 * URL is based on the package and class names. This annotation
 * allows developers to change the URL or invoke a different
 * method. This also allows developers to specify multiple URLs
 * that will be handled by a single class or a single method.
 * </p>
 * <p>
 * This can also be used via the {@link Actions} annotation
 * to associate multiple URLs with a single method.
 * </p>
 * <p>
 * Here's an example:
 * </p>
 *
 * <pre>
 * public class MyAction implements Action {
 *   {@code @Action("/foo/bar")}
 *   public String execute() {}
 * }
 * </pre>
 * <!-- END SNIPPET: javadoc -->
 */
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface Action {
    String DEFAULT_VALUE = "DEFAULT_VALUE";

    /**
     * Allows actions to specify different URLs rather than the default that is based on the package
     * and action name. This also allows methods other than execute() to be invoked or multiple URLs
     * to map to a single class or a single method to handle multiple URLs.
     *
     * @return  The action URL.
     */
    String value() default DEFAULT_VALUE;

    /**
     * Allows action methods to specifically control the results for specific return values. These
     * results are not used for other method/URL invocations on the action. These are only used for
     * the URL that this action is associated with.
     *
     * @return  The results for the action.
     */
    Result[] results() default {};

    /**
     * Allows action methods to specify what interceptors must be applied to it.
     * @return Interceptors to be applied to the action
     */
    InterceptorRef[] interceptorRefs() default {};

    /**
     * @return  The parameters passed to the action. This is a list of strings that form a name/value
     *          pair chain since creating a Map for annotations is not possible. An example would be:
     *          <code>{"key", "value", "key2", "value2"}.
     */
    String[] params() default {};

    /**
     * @return Maps return codes to exceptions. The "exceptions" interceptor must be applied to the action.
     */
    ExceptionMapping[] exceptionMappings() default {};
}