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1   /*
2    * Copyright 2002,2004 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  
17  package org.apache.commons.jelly;
18  
19  import java.util.HashMap;
20  
21  import java.util.Map;
22  
23  /*** 
24   * <p><code>MapTag</code> is a DynaTag implementation which uses a Map
25   * to store its attribute values in. Derived tags can then process this
26   * Map, change values, add or remove attributes or perform some other form
27   * of processsing pretty easily.
28   * </p>
29   *
30   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
31   * @version $Revision: 155420 $
32   */
33  
34  public abstract class MapTagSupport extends DynaTagSupport {
35  
36      private Map map;
37  
38      /*** Sets an attribute value of this tag before the tag is invoked
39       */
40      public void setAttribute(String name, Object value) {
41          getAttributes().put(name, value);
42      }
43  
44      /*** 
45       * Helper method which allows derived tags to access the attributes
46       * associated with this tag
47       */
48      protected Map getAttributes() {
49          if (map == null) {
50              map = createAttributes();
51          }
52          return map;
53      }
54      /***
55       * A Factory Method which allows derived tags to overload the Map
56       * implementation used by this tag
57       */
58  
59      protected Map createAttributes() {
60          return new HashMap();
61      }
62  
63  }