UseListTag


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  package org.apache.commons.jelly.tags.core;
17  
18  import java.util.ArrayList  ;
19  import java.util.Iterator  ;
20  import java.util.List  ;
21  import java.util.Map  ;
22  
23  import org.apache.commons.jelly.JellyTagException;
24  import org.apache.commons.jelly.expression.Expression;
25  import org.apache.commons.jelly.impl.CollectionTag;
26  
27  /**
28   * A tag which creates a List implementation and optionally
29   * adds all of the elements identified by the items attribute.
30   * The exact implementation of List can be specified via the
31   * class attribute
32   * </pre>
33   *
34   * @author <a HREF="mailto:jstrachan@apache.org">James Strachan</a>
35   * @version $Revision: 155420 $
36   */
37  public class UseListTag extends UseBeanTag implements CollectionTag {
38  
39      private Expression items;
40  
41      public UseListTag(){
42      }
43  
44      public List   getList() {
45          return (List  ) getBean();
46      }
47  
48  
49      // CollectionTag interface
50      //-------------------------------------------------------------------------
51      public void addItem(Object   value) {
52          getList().add(value);
53      }
54  
55      // DynaTag interface
56      //-------------------------------------------------------------------------
57      public Class   getAttributeType(String   name) throws JellyTagException {
58          if (name.equals("items")) {
59              return Expression.class;
60          }
61          return super.getAttributeType(name);
62      }
63  
64  
65      // Implementation methods
66      //-------------------------------------------------------------------------
67  
68      protected void setBeanProperties(Object   bean, Map   attributes) throws JellyTagException {
69          items = (Expression) attributes.remove("items");
70          super.setBeanProperties(bean, attributes);
71      }
72  
73      protected void processBean(String   var, Object   bean) throws JellyTagException {
74          super.processBean(var, bean);
75  
76          List   list = getList();
77  
78          // if the items variable is specified lets append all the items
79          if (items != null) {
80              Iterator   iter = items.evaluateAsIterator(context);
81              while (iter.hasNext()) {
82                  list.add( iter.next() );
83              }
84          }
85      }
86  
87      protected Class   getDefaultClass() {
88          return ArrayList  .class;
89      }
90  }
91
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags