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1   /*
2    * Copyright 1999-2004 The Apache Software Foundation
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.chain.web.servlet;
17  
18  
19  import javax.servlet.http.HttpServletRequest;
20  import org.apache.commons.chain.Catalog;
21  import org.apache.commons.chain.Command;
22  import org.apache.commons.chain.Context;
23  
24  
25  /***
26   * <p>{@link Command} that uses a specified request parameter
27   * to select a {@link Command} from the appropriate {@link Catalog}, and
28   * execute it.  To use this command, you would typically map an instance
29   * of {@link ChainProcessor} to a wildcard pattern like "*.execute" and
30   * then arrange that this is the default command to be executed.  In such
31   * an environment, a request for the context-relative path
32   * "/foo.execute?command=bar" would cause the "/bar" command to be loaded
33   * and executed.</p>
34   *
35   * @author Craig R. McClanahan
36   */
37  
38  public class RequestParameterMapper implements Command {
39  
40  
41      // ------------------------------------------------------ Instance Variables
42  
43  
44      private String catalogKey = ChainProcessor.CATALOG_DEFAULT;
45      private String parameter = "command";
46  
47  
48      // -------------------------------------------------------------- Properties
49  
50  
51      /***
52       * <p>Return the context key under which our {@link Catalog} has been
53       * stored.</p>
54       */
55      public String getCatalogKey() {
56  
57          return (this.catalogKey);
58  
59      }
60  
61  
62      /***
63       * <p>Set the context key under which our {@link Catalog} has been
64       * stored.</p>
65       *
66       * @param catalogKey The new catalog key
67       */
68      public void setCatalogKey(String catalogKey) {
69  
70          this.catalogKey = catalogKey;
71  
72      }
73  
74  
75      /***
76       * <p>Return the name of the request parameter to use for
77       * selecting the {@link Command} to be executed.</p>
78       */
79      public String getParameter() {
80  
81          return (this.parameter);
82  
83      }
84  
85  
86      /***
87       * <p>Set the name of the request parameter to use for
88       * selecting the {@link Command} to be executed.</p>
89       *
90       * @param parameter The new parameter name
91       */
92      public void setParameter(String parameter) {
93  
94          this.parameter = parameter;
95  
96      }
97  
98  
99      // --------------------------------------------------------- Command Methods
100 
101 
102     /***
103      * <p>Look up the specified request paramater for this request, and use it
104      * to select an appropriate {@link Command} to be executed.
105      *
106      * @param context Context for the current request
107      */
108     public boolean execute(Context context) throws Exception {
109 
110         // Look up the specified request parameter for this request
111         ServletWebContext swcontext = (ServletWebContext) context;
112         HttpServletRequest request = swcontext.getRequest();
113         String value = request.getParameter(getParameter());
114 
115         // Map to the Command specified by the extra path info
116         Catalog catalog = (Catalog) context.get(getCatalogKey());
117         Command command = catalog.getCommand(value);
118         return (command.execute(context));
119 
120     }
121 
122 
123 }