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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  package org.apache.commons.jelly.tags.fmt;
17  
18  import org.apache.commons.jelly.JellyTagException;
19  import org.apache.commons.jelly.XMLOutput;
20  import org.apache.commons.jelly.Tag;
21  import org.apache.commons.jelly.TagSupport;
22  import org.apache.commons.jelly.expression.Expression;
23  
24  /***
25   * Support for tag handlers for <param>, the parameter setting
26   * tag in JSTL.
27   * @author <a href="mailto:willievu@yahoo.com">Willie Vu</a>
28   * @version 1.1
29   *
30   * @task handle body content trimming
31   */
32  public class ParamTag extends TagSupport {
33  
34      /*** Holds value of property value. */
35      private Expression value;
36  
37      /*** Creates a new instance of ParamTag */
38      public ParamTag() {
39      }
40  
41      /***
42       * Evaluates this tag after all the tags properties have been initialized.
43       *
44       */
45      public void doTag(XMLOutput output) throws JellyTagException {
46          MessageTag parent = null;
47          Tag t = findAncestorWithClass(this, MessageTag.class);
48          if (t != null) {
49              parent = (MessageTag) t;
50          } else {
51              // must be nested inside a <fmt:message> action.
52              throw new JellyTagException("must be nested inside a <fmt:message> action.");
53          }
54  
55          Object valueInput = null;
56          if (this.value != null) {
57              valueInput = this.value.evaluate(context);
58          }
59          else {
60              // get value from body
61              valueInput = getBodyText();
62          }
63  
64          parent.addParam(valueInput);
65      }
66  
67      /*** Setter for property value.
68       * @param value New value of property value.
69       *
70       */
71      public void setValue(Expression value) {
72          this.value = value;
73      }
74  
75  }