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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: 1.6 $
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 }