Struts example source code file (CompositeActionMapper.java)

This example Struts source code file (CompositeActionMapper.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

actionmapper, actionmapper, actionmapping, actionmapping, arraylist, compositeactionmapper, configurationmanager, http, inject, logger, object, request, response, servlet, string, string, using, using, util

The Struts CompositeActionMapper.java source code

/*
 * $Id: CompositeActionMapper.java 791919 2009-07-07 17:47:34Z 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.dispatcher.mapper;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.StrutsConstants;

import com.opensymphony.xwork2.config.ConfigurationManager;
import com.opensymphony.xwork2.inject.Container;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;

/**
 * <!-- START SNIPPET: description -->
 *
 * A composite action mapper that is capable of delegating to a series of {@link ActionMapper} if the former
 * failed to obtained a valid {@link ActionMapping} or uri.
 * <p/>
 * It is configured through struts.properties.
 * <p/>
 * For example, with the following entries in struts.properties
 * <p/>
 * <pre>
 * <bean type="org.apache.struts2.dispatcher.mapper.ActionMapper" name="struts" 
 *       class="org.apache.struts2.dispatcher.mapper.CompositeActionMapper" />
 * <constant name="struts.mapper.composite" 
 *       value="org.apache.struts2.dispatcher.mapper.DefaultActionMapper,org.apache.struts2.dispatcher.mapper.RestfulActionMapper,org.apache.struts2.dispatcher.mapper.Restful2ActionMapper" />
 * </pre>
 * <p/>
 * When {@link CompositeActionMapper#getMapping(HttpServletRequest, ConfigurationManager)} or
 * {@link CompositeActionMapper#getUriFromActionMapping(ActionMapping)} is invoked,
 * {@link CompositeActionMapper} would go through these {@link ActionMapper}s in sequence
 * starting from {@link ActionMapper} identified by 'struts.mapper.composite.1', followed by
 * 'struts.mapper.composite.2' and finally 'struts.mapper.composite.3' (in this case) until either
 * one of the {@link ActionMapper} return a valid result (not null) or it runs out of {@link ActionMapper}
 * in which case it will just return null for both
 * {@link CompositeActionMapper#getMapping(HttpServletRequest, ConfigurationManager)} and
 * {@link CompositeActionMapper#getUriFromActionMapping(ActionMapping)} methods.
 * <p/>
 *
 * For example with the following in struts-*.xml :-
 * <pre>
 *    <bean type="org.apache.struts2.dispatcher.mapper.ActionMapper" name="struts" 
 *       class="org.apache.struts2.dispatcher.mapper.CompositeActionMapper" />
 *    <constant name="struts.mapper.composite" 
 *       value="org.apache.struts2.dispatcher.mapper.DefaultActionMapper,foo.bar.MyActionMapper,foo.bar.MyAnotherActionMapper" />
 * </pre>
 * <p/>
 * <code>CompositeActionMapper will be configured with 3 ActionMapper, namely
 * "DefaultActionMapper", "MyActionMapper" and "MyAnotherActionMapper".
 * <code>CompositeActionMapper would consult each of them in order described above.
 *
 * <!-- END SNIPPET: description -->
 *
 * @see ActionMapper
 * @see ActionMapping
 *
 * @version $Date: 2009-07-07 19:47:34 +0200 (Tue, 07 Jul 2009) $ $Id: CompositeActionMapper.java 791919 2009-07-07 17:47:34Z musachy $
 */
public class CompositeActionMapper implements ActionMapper {

    private static final Logger LOG = LoggerFactory.getLogger(CompositeActionMapper.class);

    protected Container container;
    
    protected List<ActionMapper> actionMappers = new ArrayList();
    
    @Inject
    public void setContainer(Container container) {
        this.container = container;
    }
    
    @Inject(StrutsConstants.STRUTS_MAPPER_COMPOSITE)
    public void setActionMappers(String list) {
        if (list != null) {
            String[] arr = list.split(",");
            for (String name : arr) {
                Object obj = container.getInstance(ActionMapper.class, name);
                if (obj != null) {
                    actionMappers.add((ActionMapper) obj);
                }
            }
        }
    }


    public ActionMapping getMapping(HttpServletRequest request, ConfigurationManager configManager) {

        for (ActionMapper actionMapper : actionMappers) {
            ActionMapping actionMapping = actionMapper.getMapping(request, configManager);
            if (LOG.isDebugEnabled()) {
                LOG.debug("Using ActionMapper "+actionMapper);
            }
            if (actionMapping == null) {
                if (LOG.isDebugEnabled()) {
                    LOG.debug("ActionMapper "+actionMapper+" failed to return an ActionMapping (null)");
                }
            }
            else {
                return actionMapping;
            }
        }
        if (LOG.isDebugEnabled()) {
            LOG.debug("exhausted from ActionMapper that could return an ActionMapping");
        }
        return null;
    }

    public ActionMapping getMappingFromActionName(String actionName) {

        for (ActionMapper actionMapper : actionMappers) {
            ActionMapping actionMapping = actionMapper.getMappingFromActionName(actionName);
            if (LOG.isDebugEnabled()) {
                LOG.debug("Using ActionMapper "+actionMapper);
            }
            if (actionMapping == null) {
                if (LOG.isDebugEnabled()) {
                    LOG.debug("ActionMapper "+actionMapper+" failed to return an ActionMapping (null)");
                }
            }
            else {
                return actionMapping;
            }
        }
        if (LOG.isDebugEnabled()) {
            LOG.debug("exhausted from ActionMapper that could return an ActionMapping");
        }
        return null;
    }

    public String getUriFromActionMapping(ActionMapping mapping) {

        for (ActionMapper actionMapper : actionMappers) {
            String uri = actionMapper.getUriFromActionMapping(mapping);
            if (LOG.isDebugEnabled()) {
                LOG.debug("Using ActionMapper "+actionMapper);
            }
            if (uri == null) {
                if (LOG.isDebugEnabled()) {
                    LOG.debug("ActionMapper "+actionMapper+" failed to return an ActionMapping (null)");
                }
            }
            else {
                return uri;
            }
        }
        if (LOG.isDebugEnabled()) {
            LOG.debug("exhausted from ActionMapper that could return a uri");
        }
        return null;
    }
}