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16 package org.apache.commons.jelly.tags.core;
17
18 import org.apache.commons.jelly.JellyTagException;
19 import org.apache.commons.jelly.TagSupport;
20 import org.apache.commons.jelly.XMLOutput;
21 import org.apache.commons.jelly.expression.Expression;
22 import org.xml.sax.SAXException;
23
24 /*** A tag which evaluates an expression
25 *
26 * @tag out
27 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
28 * @version $Revision: 155420 $
29 */
30 public class ExprTag extends TagSupport {
31
32 /*** The expression to evaluate. */
33 private Expression value;
34
35 public ExprTag() {
36 }
37
38
39
40 public void doTag(XMLOutput output) throws JellyTagException {
41 if (value != null) {
42 String text = value.evaluateAsString(context);
43 if (text != null) {
44
45 try {
46 output.write(text);
47 }
48 catch (SAXException e) {
49 throw new JellyTagException("could not write the XMLOutput",e);
50 }
51 }
52 }
53 }
54
55
56
57
58 /***
59 * Sets the Jexl expression to evaluate.
60 *
61 * @required true
62 */
63 public void setValue(Expression value) {
64 this.value = value;
65 }
66 }