KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > apache > commons > jelly > impl > ExpressionScript


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.impl;
17
18 import org.apache.commons.jelly.JellyContext;
19 import org.apache.commons.jelly.JellyTagException;
20 import org.apache.commons.jelly.Script;
21 import org.apache.commons.jelly.XMLOutput;
22 import org.apache.commons.jelly.expression.Expression;
23
24 import org.xml.sax.SAXException JavaDoc;
25
26 /**
27  * <p><code>ExpressionScript</code> outputs the value of an expression as text.</p>
28  *
29  * @author <a HREF="mailto:jstrachan@apache.org">James Strachan</a>
30  * @version $Revision: 155420 $
31  */
32 public class ExpressionScript implements Script {
33
34     /** the expression evaluated as a String and output by this script */
35     private Expression expression;
36
37     public ExpressionScript() {
38     }
39
40     public ExpressionScript(Expression expression) {
41         this.expression = expression;
42     }
43
44     public String JavaDoc toString() {
45         return super.toString() + "[expression=" + expression + "]";
46     }
47
48     /** @return the expression evaluated as a String and output by this script */
49     public Expression getExpression() {
50         return expression;
51     }
52
53     /** Sets the expression evaluated as a String and output by this script */
54     public void setExpression(Expression expression) {
55         this.expression = expression;
56     }
57
58     // Script interface
59 //-------------------------------------------------------------------------
60 public Script compile() {
61         return this;
62     }
63
64     /** Evaluates the body of a tag */
65     public void run(JellyContext context, XMLOutput output) throws JellyTagException {
66         Object JavaDoc result = expression.evaluate(context);
67         if ( result != null ) {
68
69             try {
70               output.objectData(result);
71             } catch (SAXException JavaDoc e) {
72                 throw new JellyTagException("Could not write to XMLOutput",e);
73             }
74
75         }
76     }
77 }
78
Popular Tags