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Java > Open Source Codes > org > jaxen > javabean > JavaBeanXPath


1 /*
2  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/javabean/JavaBeanXPath.java,v 1.3 2005/01/30 03:11:13 elharo Exp $
3  * $Revision: 1.3 $
4  * $Date: 2005/01/30 03:11:13 $
5  *
6  * ====================================================================
7  *
8  * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  *
15  * 1. Redistributions of source code must retain the above copyright
16  * notice, this list of conditions, and the following disclaimer.
17  *
18  * 2. Redistributions in binary form must reproduce the above copyright
19  * notice, this list of conditions, and the disclaimer that follows
20  * these conditions in the documentation and/or other materials
21  * provided with the distribution.
22  *
23  * 3. The name "Jaxen" must not be used to endorse or promote products
24  * derived from this software without prior written permission. For
25  * written permission, please contact license@jaxen.org.
26  *
27  * 4. Products derived from this software may not be called "Jaxen", nor
28  * may "Jaxen" appear in their name, without prior written permission
29  * from the Jaxen Project Management (pm@jaxen.org).
30  *
31  * In addition, we request (but do not require) that you include in the
32  * end-user documentation provided with the redistribution and/or in the
33  * software itself an acknowledgement equivalent to the following:
34  * "This product includes software developed by the
35  * Jaxen Project (http://www.jaxen.org/)."
36  * Alternatively, the acknowledgment may be graphical using the logos
37  * available at http://www.jaxen.org/
38  *
39  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42  * DISCLAIMED. IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * ====================================================================
53  * This software consists of voluntary contributions made by many
54  * individuals on behalf of the Jaxen Project and was originally
55  * created by bob mcwhirter <bob@werken.com> and
56  * James Strachan <jstrachan@apache.org>. For more information on the
57  * Jaxen Project, please see <http://www.jaxen.org/>.
58  *
59  * $Id: JavaBeanXPath.java,v 1.3 2005/01/30 03:11:13 elharo Exp $
60  */
61
62 package org.jaxen.javabean;
63
64 import org.jaxen.Context;
65 import org.jaxen.BaseXPath;
66 import org.jaxen.JaxenException;
67
68 import java.util.List JavaDoc;
69 import java.util.ArrayList JavaDoc;
70 import java.util.Collection JavaDoc;
71 import java.util.Iterator JavaDoc;
72
73 /** An XPath implementation for JavaBeans.
74  *
75  * <p>This is the main entry point for matching an XPath against a JavaBean
76  * tree. You create a compiled XPath object, then match it against
77  * one or more context nodes using the {@link #selectNodes(Object)}
78  * method, as in the following example:</p>
79  *
80  * <pre>
81  * Node node = ...;
82  * XPath path = new JavaBeanXPath("a/b/c");
83  * List results = path.selectNodes(node);
84  * </pre>
85  *
86  * @see BaseXPath
87  *
88  * @author <a HREF="mailto:bob@werken.com">bob mcwhirter</a>
89  *
90  * @version $Revision: 1.3 $
91  */
92 public class JavaBeanXPath extends BaseXPath
93 {
94     /** Construct given an XPath expression string.
95      *
96      * @param xpathExpr The XPath expression.
97      *
98      * @throws JaxenException if there is a syntax error while
99      * parsing the expression
100      */
101     public JavaBeanXPath(String JavaDoc xpathExpr) throws JaxenException
102     {
103         super( xpathExpr, DocumentNavigator.getInstance() );
104     }
105
106     protected Context getContext(Object JavaDoc node)
107     {
108         if ( node instanceof Context )
109         {
110             return (Context) node;
111         }
112
113         if ( node instanceof Element )
114         {
115             return super.getContext( node );
116         }
117
118         if ( node instanceof List JavaDoc )
119         {
120             List JavaDoc newList = new ArrayList JavaDoc();
121
122             for ( Iterator JavaDoc listIter = ((List JavaDoc)node).iterator();
123                   listIter.hasNext(); )
124             {
125                 newList.add( new Element( null, "root", listIter.next() ) );
126             }
127
128             return super.getContext( newList );
129         }
130
131         return super.getContext( new Element( null, "root", node ) );
132     }
133
134     public Object JavaDoc evaluate(Object JavaDoc node)
135         throws JaxenException
136     {
137         Object JavaDoc result = super.evaluate( node );
138
139         if ( result instanceof Element )
140         {
141             return ((Element)result).getObject();
142         }
143         else if ( result instanceof Collection JavaDoc )
144         {
145             List JavaDoc newList = new ArrayList JavaDoc();
146
147             for ( Iterator JavaDoc listIter = ((Collection JavaDoc)result).iterator();
148                   listIter.hasNext(); )
149             {
150                 Object JavaDoc member = listIter.next();
151
152                 if ( member instanceof Element )
153                 {
154                     newList.add( ((Element)member).getObject() );
155                 }
156                 else
157                 {
158                     newList.add( member );
159                 }
160             }
161
162             return newList;
163         }
164
165         return result;
166     }
167 }
168
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