1 /*
2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/tags/xml/ExprTag.java,v 1.6 2002/05/16 18:20:35 jstrachan Exp $
3 * $Revision: 1.6 $
4 * $Date: 2002/05/16 18:20:35 $
5 *
6 * ====================================================================
7 *
8 * The Apache Software License, Version 1.1
9 *
10 * Copyright (c) 1999-2002 The Apache Software Foundation. All rights
11 * reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 *
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in
22 * the documentation and/or other materials provided with the
23 * distribution.
24 *
25 * 3. The end-user documentation included with the redistribution, if
26 * any, must include the following acknowlegement:
27 * "This product includes software developed by the
28 * Apache Software Foundation (http://www.apache.org/)."
29 * Alternately, this acknowlegement may appear in the software itself,
30 * if and wherever such third-party acknowlegements normally appear.
31 *
32 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
33 * Foundation" must not be used to endorse or promote products derived
34 * from this software without prior written permission. For written
35 * permission, please contact apache@apache.org.
36 *
37 * 5. Products derived from this software may not be called "Apache"
38 * nor may "Apache" appear in their names without prior written
39 * permission of the Apache Group.
40 *
41 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52 * SUCH DAMAGE.
53 * ====================================================================
54 *
55 * This software consists of voluntary contributions made by many
56 * individuals on behalf of the Apache Software Foundation. For more
57 * information on the Apache Software Foundation, please see
58 * <http://www.apache.org/>.
59 *
60 * $Id: ExprTag.java,v 1.6 2002/05/16 18:20:35 jstrachan Exp $
61 */
62 package org.apache.commons.jelly.tags.xml;
63
64 import org.apache.commons.jelly.JellyContext;
65 import org.apache.commons.jelly.MissingAttributeException;
66 import org.apache.commons.jelly.Script;
67 import org.apache.commons.jelly.TagSupport;
68 import org.apache.commons.jelly.XMLOutput;
69
70 import org.jaxen.XPath;
71
72 /***
73 * Evaluates the XPath expression to be a boolean and only evaluates the body
74 * if the expression is true.
75 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
76 * @version $Revision: 1.6 $
77 */
78 public class IfTag extends XPathTagSupport {
79
80 /*** The XPath expression to evaluate. */
81 private XPath select;
82
83 public IfTag() {
84 }
85
86 // Tag interface
87 //-------------------------------------------------------------------------
88 public void doTag(XMLOutput output) throws Exception {
89 if (select == null) {
90 throw new MissingAttributeException( "select" );
91 }
92
93 Object xpathContext = getXPathContext();
94 if ( select.booleanValueOf(xpathContext) ) {
95 invokeBody(output);
96 }
97 }
98
99 // Properties
100 //-------------------------------------------------------------------------
101
102 /*** Sets the XPath expression to evaluate. */
103 public void setSelect(XPath select) {
104 this.select = select;
105 }
106
107 // Implementation methods
108 //-------------------------------------------------------------------------
109 protected Object getXPathContext() {
110 ForEachTag tag = (ForEachTag) findAncestorWithClass( ForEachTag.class );
111 if ( tag != null ) {
112 return tag.getXPathContext();
113 }
114 return null;
115 }
116
117 }
This page was automatically generated by Maven