1 /* 2 * $Header$ 3 * $Revision$ 4 * $Date$ 5 * 6 * ==================================================================== 7 * 8 * Copyright 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 are 13 * met: 14 * 15 * * Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 18 * * Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 22 * * Neither the name of the Jaxen Project nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 27 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 29 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER 30 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 32 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 33 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 36 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 * 38 * ==================================================================== 39 * This software consists of voluntary contributions made by many 40 * individuals on behalf of the Jaxen Project and was originally 41 * created by bob mcwhirter <bob@werken.com> and 42 * James Strachan <jstrachan@apache.org>. For more information on the 43 * Jaxen Project, please see <http://www.jaxen.org/>. 44 * 45 * $Id$ 46 */ 47 48 package org.jaxen.javabean; 49 50 import org.jaxen.Context; 51 import org.jaxen.BaseXPath; 52 import org.jaxen.JaxenException; 53 54 import java.util.List; 55 import java.util.ArrayList; 56 import java.util.Collection; 57 import java.util.Iterator; 58 59 /** An XPath implementation for JavaBeans. 60 * 61 * <p>This is the main entry point for matching an XPath against a JavaBean 62 * tree. You create a compiled XPath object, then match it against 63 * one or more context nodes using the {@link #selectNodes(Object)} 64 * method, as in the following example:</p> 65 * 66 * <pre> 67 * Node node = ...; 68 * XPath path = new JavaBeanXPath("a/b/c"); 69 * List results = path.selectNodes(node); 70 * </pre> 71 * 72 * @see BaseXPath 73 * 74 * @author <a href="mailto:bob@werken.com">bob mcwhirter</a> 75 * 76 * @version $Revision$ 77 */ 78 public class JavaBeanXPath extends BaseXPath 79 { 80 /** 81 * 82 */ 83 private static final long serialVersionUID = -1567521943360266313L; 84 85 /** Construct given an XPath expression string. 86 * 87 * @param xpathExpr The XPath expression. 88 * 89 * @throws JaxenException if there is a syntax error while 90 * parsing the expression 91 */ 92 public JavaBeanXPath(String xpathExpr) throws JaxenException 93 { 94 super( xpathExpr, DocumentNavigator.getInstance() ); 95 } 96 97 protected Context getContext(Object node) 98 { 99 if ( node instanceof Context ) 100 { 101 return (Context) node; 102 } 103 104 if ( node instanceof Element ) 105 { 106 return super.getContext( node ); 107 } 108 109 if ( node instanceof List ) 110 { 111 List newList = new ArrayList(); 112 113 for ( Iterator listIter = ((List)node).iterator(); 114 listIter.hasNext(); ) 115 { 116 newList.add( new Element( null, "root", listIter.next() ) ); 117 } 118 119 return super.getContext( newList ); 120 } 121 122 return super.getContext( new Element( null, "root", node ) ); 123 } 124 125 public Object evaluate(Object node) 126 throws JaxenException 127 { 128 Object result = super.evaluate( node ); 129 130 if ( result instanceof Element ) 131 { 132 return ((Element)result).getObject(); 133 } 134 else if ( result instanceof Collection ) 135 { 136 List newList = new ArrayList(); 137 138 for ( Iterator listIter = ((Collection)result).iterator(); 139 listIter.hasNext(); ) 140 { 141 Object member = listIter.next(); 142 143 if ( member instanceof Element ) 144 { 145 newList.add( ((Element)member).getObject() ); 146 } 147 else 148 { 149 newList.add( member ); 150 } 151 } 152 153 return newList; 154 } 155 156 return result; 157 } 158 }