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1   /*
2    * $Id: CreateAction.java 510851 2007-02-23 07:05:18Z pbenedict $
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  package org.apache.struts.chain.commands.servlet;
22  
23  import org.apache.commons.logging.Log;
24  import org.apache.commons.logging.LogFactory;
25  import org.apache.struts.action.Action;
26  import org.apache.struts.action.ActionServlet;
27  import org.apache.struts.chain.Constants;
28  import org.apache.struts.chain.commands.util.ClassUtils;
29  import org.apache.struts.chain.contexts.ActionContext;
30  import org.apache.struts.chain.contexts.ServletActionContext;
31  import org.apache.struts.config.ActionConfig;
32  import org.apache.struts.config.ModuleConfig;
33  
34  import java.util.HashMap;
35  import java.util.Map;
36  
37  /**
38   * <p>Concrete implementation of <code>AbstractCreateAction</code> for use in
39   * a Servlet API chain.  Expects that the ActionContext passed into it can
40   * safely be cast to <code>ServletActionContext</code>.</p>
41   */
42  public class CreateAction
43      extends org.apache.struts.chain.commands.AbstractCreateAction {
44      // ------------------------------------------------------ Instance Variables
45      private static final Log log = LogFactory.getLog(CreateAction.class);
46  
47      /* :TODO The Action class' dependency on having its "servlet" property set
48       * requires this API-dependent subclass of AbstractCreateAction.
49       */
50      protected synchronized Action getAction(ActionContext context, String type,
51          ActionConfig actionConfig)
52          throws Exception {
53          ModuleConfig moduleConfig = actionConfig.getModuleConfig();
54          String actionsKey = Constants.ACTIONS_KEY + moduleConfig.getPrefix();
55          Map actions = (Map) context.getApplicationScope().get(actionsKey);
56  
57          if (actions == null) {
58              actions = new HashMap();
59              context.getApplicationScope().put(actionsKey, actions);
60          }
61  
62          Action action = null;
63  
64          synchronized (actions) {
65              action = (Action) actions.get(type);
66  
67              if (action == null) {
68                  action = createAction(context, type);
69                  actions.put(type, action);
70              }
71          }
72  
73          if (action.getServlet() == null) {
74              ServletActionContext saContext = (ServletActionContext) context;
75              ActionServlet actionServlet = saContext.getActionServlet();
76  
77              action.setServlet(actionServlet);
78          }
79  
80          return (action);
81      }
82  
83      
84      /**
85       * <p>Invoked by <code>getAction</code> when the <code>Action</code> 
86       * actually has to be created. If the instance is already created and 
87       * cached, this method will not be called. </p>
88       * 
89       * @param context      The <code>Context</code> for this request
90       * @param type         Name of class to instantiate
91       * @return Instantiated Action class
92       * @throws Exception if there are any problems instantiating the Action
93       *                   class.
94       * @since Struts 1.3.7
95       */
96      protected Action createAction(ActionContext context, String type) throws Exception {
97          log.info("Initialize action of type: " + type);
98          return (Action) ClassUtils.getApplicationInstance(type);
99      }
100 }