| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||||
| BaseXPath |
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| 1.8148148148148149;1.815 |
| 1 | /* |
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| 2 | * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/BaseXPath.java,v 1.48 2005/09/24 23:05:15 elharo Exp $ |
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| 3 | * $Revision: 1.48 $ |
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| 4 | * $Date: 2005/09/24 23:05:15 $ |
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| 5 | * |
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| 6 | * ==================================================================== |
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| 7 | * |
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| 8 | * Copyright (C) 2000-2002 bob mcwhirter & James Strachan. |
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| 9 | * All rights reserved. |
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| 10 | * |
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| 11 | * Redistribution and use in source and binary forms, with or without |
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| 12 | * modification, are permitted provided that the following conditions |
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| 13 | * are met: |
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| 14 | * |
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| 15 | * 1. Redistributions of source code must retain the above copyright |
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| 16 | * notice, this list of conditions, and the following disclaimer. |
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| 17 | * |
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| 18 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 19 | * notice, this list of conditions, and the disclaimer that follows |
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| 20 | * these conditions in the documentation and/or other materials |
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| 21 | * provided with the distribution. |
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| 22 | * |
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| 23 | * 3. The name "Jaxen" must not be used to endorse or promote products |
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| 24 | * derived from this software without prior written permission. For |
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| 25 | * written permission, please contact license@jaxen.org. |
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| 26 | * |
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| 27 | * 4. Products derived from this software may not be called "Jaxen", nor |
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| 28 | * may "Jaxen" appear in their name, without prior written permission |
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| 29 | * from the Jaxen Project Management (pm@jaxen.org). |
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| 30 | * |
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| 31 | * In addition, we request (but do not require) that you include in the |
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| 32 | * end-user documentation provided with the redistribution and/or in the |
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| 33 | * software itself an acknowledgement equivalent to the following: |
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| 34 | * "This product includes software developed by the |
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| 35 | * Jaxen Project <http://www.jaxen.org/>." |
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| 36 | * Alternatively, the acknowledgment may be graphical using the logos |
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| 37 | * available at http://www.jaxen.org/ |
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| 38 | * |
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| 39 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
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| 40 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 41 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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| 42 | * DISCLAIMED. IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT |
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| 43 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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| 44 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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| 45 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
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| 46 | * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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| 47 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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| 48 | * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
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| 49 | * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| 50 | * SUCH DAMAGE. |
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| 51 | * |
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| 52 | * ==================================================================== |
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| 53 | * This software consists of voluntary contributions made by many |
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| 54 | * individuals on behalf of the Jaxen Project and was originally |
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| 55 | * created by bob mcwhirter <bob@werken.com> and |
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| 56 | * James Strachan <jstrachan@apache.org>. For more information on the |
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| 57 | * Jaxen Project, please see <http://www.jaxen.org/>. |
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| 58 | * |
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| 59 | * $Id: BaseXPath.java,v 1.48 2005/09/24 23:05:15 elharo Exp $ |
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| 60 | */ |
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| 61 | ||
| 62 | ||
| 63 | package org.jaxen; |
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| 64 | ||
| 65 | import java.io.Serializable; |
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| 66 | import java.util.List; |
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| 67 | ||
| 68 | import org.jaxen.expr.Expr; |
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| 69 | import org.jaxen.expr.XPathExpr; |
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| 70 | import org.jaxen.function.BooleanFunction; |
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| 71 | import org.jaxen.function.NumberFunction; |
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| 72 | import org.jaxen.function.StringFunction; |
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| 73 | import org.jaxen.saxpath.SAXPathException; |
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| 74 | import org.jaxen.saxpath.XPathReader; |
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| 75 | import org.jaxen.saxpath.helpers.XPathReaderFactory; |
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| 76 | import org.jaxen.util.SingletonList; |
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| 77 | ||
| 78 | /** Base functionality for all concrete, implementation-specific XPaths. |
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| 79 | * |
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| 80 | * <p> |
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| 81 | * This class provides generic functionality for further-defined |
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| 82 | * implementation-specific XPaths. |
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| 83 | * </p> |
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| 84 | * |
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| 85 | * <p> |
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| 86 | * If you want to adapt the Jaxen engine so that it can traverse your own |
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| 87 | * object model, then this is a good base class to derive from. |
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| 88 | * Typically you only really need to provide your own |
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| 89 | * {@link org.jaxen.Navigator} implementation. |
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| 90 | * </p> |
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| 91 | * |
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| 92 | * @see org.jaxen.dom4j.Dom4jXPath XPath for dom4j |
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| 93 | * @see org.jaxen.jdom.JDOMXPath XPath for JDOM |
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| 94 | * @see org.jaxen.dom.DOMXPath XPath for W3C DOM |
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| 95 | * |
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| 96 | * @author <a href="mailto:bob@werken.com">bob mcwhirter</a> |
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| 97 | * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> |
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| 98 | */ |
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| 99 | public class BaseXPath implements XPath, Serializable |
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| 100 | { |
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| 101 | /** Original expression text. */ |
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| 102 | private String exprText; |
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| 103 | ||
| 104 | /** the parsed form of the XPath expression */ |
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| 105 | private XPathExpr xpath; |
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| 106 | ||
| 107 | /** the support information and function, namespace and variable contexts */ |
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| 108 | private ContextSupport support; |
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| 109 | ||
| 110 | /** the implementation-specific Navigator for retrieving XML nodes **/ |
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| 111 | private Navigator navigator; |
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| 112 | ||
| 113 | /** Construct given an XPath expression string. |
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| 114 | * |
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| 115 | * @param xpathExpr the XPath expression |
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| 116 | * |
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| 117 | * @throws JaxenException if there is a syntax error while |
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| 118 | * parsing the expression |
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| 119 | */ |
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| 120 | protected BaseXPath(String xpathExpr) throws JaxenException |
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| 121 | 10578 | { |
| 122 | try |
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| 123 | { |
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| 124 | 10578 | XPathReader reader = XPathReaderFactory.createReader(); |
| 125 | 10572 | JaxenHandler handler = new JaxenHandler(); |
| 126 | 10572 | reader.setXPathHandler( handler ); |
| 127 | 10572 | reader.parse( xpathExpr ); |
| 128 | 10356 | this.xpath = handler.getXPathExpr(); |
| 129 | } |
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| 130 | 216 | catch (org.jaxen.saxpath.XPathSyntaxException e) |
| 131 | { |
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| 132 | 216 | throw new org.jaxen.XPathSyntaxException( e ); |
| 133 | } |
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| 134 | 6 | catch (SAXPathException e) |
| 135 | { |
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| 136 | 6 | throw new JaxenException( e ); |
| 137 | 10356 | } |
| 138 | ||
| 139 | 10356 | this.exprText = xpathExpr; |
| 140 | 10356 | } |
| 141 | ||
| 142 | /** Construct given an XPath expression string. |
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| 143 | * |
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| 144 | * @param xpathExpr the XPath expression |
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| 145 | * |
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| 146 | * @param navigator the XML navigator to use |
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| 147 | * |
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| 148 | * @throws JaxenException if there is a syntax error while |
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| 149 | * parsing the expression |
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| 150 | */ |
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| 151 | public BaseXPath(String xpathExpr, Navigator navigator) throws JaxenException |
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| 152 | { |
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| 153 | 3510 | this( xpathExpr ); |
| 154 | 3480 | this.navigator = navigator; |
| 155 | 3480 | } |
| 156 | ||
| 157 | /** Evaluate this XPath against a given context. |
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| 158 | * The context of evaluation may be any object type |
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| 159 | * the navigator recognizes as a node. |
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| 160 | * The return value is either a <code>String</code>, |
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| 161 | * <code>Double</code>, <code>Boolean</code>, or <code>List</code> |
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| 162 | * of nodes. |
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| 163 | * |
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| 164 | * <p> |
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| 165 | * When using this method, one must be careful to |
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| 166 | * test the class of the returned object. If the returned |
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| 167 | * object is a list, then the items in this |
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| 168 | * list will be the actual <code>Document</code>, |
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| 169 | * <code>Element</code>, <code>Attribute</code>, etc. objects |
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| 170 | * as defined by the concrete XML object-model implementation, |
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| 171 | * directly from the context document. This method <strong>does |
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| 172 | * not return <em>copies</em> of anything</strong>, but merely |
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| 173 | * returns references to objects within the source document. |
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| 174 | * </p> |
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| 175 | * |
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| 176 | * @param context the node, node-set or Context object for evaluation. |
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| 177 | * This value can be null. |
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| 178 | * |
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| 179 | * @return the result of evaluating the XPath expression |
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| 180 | * against the supplied context |
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| 181 | * @throws JaxenException if an XPath error occurs during expression evaluation |
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| 182 | * @throws ClassCastException if the context is not a node |
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| 183 | */ |
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| 184 | public Object evaluate(Object context) throws JaxenException |
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| 185 | { |
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| 186 | 4644 | List answer = selectNodes(context); |
| 187 | ||
| 188 | 4584 | if ( answer != null |
| 189 | && |
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| 190 | answer.size() == 1 ) |
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| 191 | { |
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| 192 | 4566 | Object first = answer.get(0); |
| 193 | ||
| 194 | 4566 | if ( first instanceof String |
| 195 | || |
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| 196 | first instanceof Number |
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| 197 | || |
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| 198 | first instanceof Boolean ) |
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| 199 | { |
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| 200 | 3762 | return first; |
| 201 | } |
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| 202 | } |
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| 203 | 822 | return answer; |
| 204 | } |
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| 205 | ||
| 206 | /** Select all nodes that are selected by this XPath |
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| 207 | * expression. If multiple nodes match, multiple nodes |
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| 208 | * will be returned. Nodes will be returned |
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| 209 | * in document-order, as defined by the XPath |
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| 210 | * specification. If the expression selects a non-node-set |
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| 211 | * (i.e. a number, boolean, or string) then a List |
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| 212 | * containing just that one object is returned. |
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| 213 | * </p> |
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| 214 | * |
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| 215 | * @param node the node, node-set or Context object for evaluation. |
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| 216 | * This value can be null. |
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| 217 | * |
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| 218 | * @return the node-set of all items selected |
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| 219 | * by this XPath expression |
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| 220 | * @throws JaxenException if an XPath error occurs during expression evaluation |
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| 221 | * |
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| 222 | * @see #selectNodesForContext |
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| 223 | */ |
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| 224 | public List selectNodes(Object node) throws JaxenException |
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| 225 | { |
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| 226 | 10236 | Context context = getContext( node ); |
| 227 | 10236 | return selectNodesForContext( context ); |
| 228 | } |
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| 229 | ||
| 230 | /** Select only the first node selected by this XPath |
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| 231 | * expression. If multiple nodes match, only one node will be |
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| 232 | * returned. The selected node will be the first |
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| 233 | * selected node in document-order, as defined by the XPath |
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| 234 | * specification. |
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| 235 | * </p> |
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| 236 | * |
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| 237 | * @param node the node, node-set or Context object for evaluation. |
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| 238 | * This value can be null. |
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| 239 | * |
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| 240 | * @return the node-set of all items selected |
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| 241 | * by this XPath expression |
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| 242 | * @throws JaxenException if an XPath error occurs during expression evaluation |
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| 243 | * |
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| 244 | * @see #selectNodes |
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| 245 | */ |
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| 246 | public Object selectSingleNode(Object node) throws JaxenException |
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| 247 | { |
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| 248 | 12 | List results = selectNodes( node ); |
| 249 | ||
| 250 | 12 | if ( results.isEmpty() ) |
| 251 | { |
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| 252 | 6 | return null; |
| 253 | } |
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| 254 | ||
| 255 | 6 | return results.get( 0 ); |
| 256 | } |
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| 257 | ||
| 258 | /** |
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| 259 | * Returns the XPath string-value of the argument node. |
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| 260 | * |
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| 261 | * @param node the node whose value to take |
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| 262 | * @return the XPath string value of this node |
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| 263 | * @throws JaxenException if an XPath error occurs during expression evaluation |
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| 264 | * @deprecated replaced by {@link #stringValueOf} |
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| 265 | */ |
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| 266 | public String valueOf(Object node) throws JaxenException |
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| 267 | { |
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| 268 | 0 | return stringValueOf( node ); |
| 269 | } |
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| 270 | ||
| 271 | /** Retrieves the string-value of the result of |
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| 272 | * evaluating this XPath expression when evaluated |
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| 273 | * against the specified context. |
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| 274 | * |
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| 275 | * <p> |
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| 276 | * The string-value of the expression is determined per |
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| 277 | * the <code>string(..)</code> core function defined |
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| 278 | * in the XPath specification. This means that an expression |
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| 279 | * that selects zero nodes will return the empty string, |
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| 280 | * while an expression that selects one-or-more nodes will |
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| 281 | * return the string-value of the first node. |
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| 282 | * </p> |
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| 283 | * |
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| 284 | * @param node the node, node-set or Context object for evaluation. This value can be null. |
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| 285 | * |
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| 286 | * @return the string-value of the result of evaluating this expression with the specified context node |
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| 287 | * @throws JaxenException if an XPath error occurs during expression evaluation |
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| 288 | */ |
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| 289 | public String stringValueOf(Object node) throws JaxenException |
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| 290 | { |
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| 291 | 18 | Context context = getContext( node ); |
| 292 | ||
| 293 | 18 | Object result = selectSingleNodeForContext( context ); |
| 294 | ||
| 295 | 18 | if ( result == null ) |
| 296 | { |
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| 297 | 6 | return ""; |
| 298 | } |
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| 299 | ||
| 300 | 12 | return StringFunction.evaluate( result, |
| 301 | context.getNavigator() ); |
|
| 302 | } |
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| 303 | ||
| 304 | /** Retrieve a boolean-value interpretation of this XPath |
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| 305 | * expression when evaluated against a given context. |
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| 306 | * |
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| 307 | * <p> |
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| 308 | * The boolean-value of the expression is determined per |
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| 309 | * the <code>boolean(..)</code> function defined |
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| 310 | * in the XPath specification. This means that an expression |
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| 311 | * that selects zero nodes will return <code>false</code>, |
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| 312 | * while an expression that selects one or more nodes will |
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| 313 | * return <code>true</code>. |
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| 314 | * </p> |
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| 315 | * |
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| 316 | * @param node the node, node-set or Context object for evaluation. This value can be null. |
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| 317 | * |
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| 318 | * @return the boolean-value of the result of evaluating this expression with the specified context node |
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| 319 | * @throws JaxenException if an XPath error occurs during expression evaluation |
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| 320 | */ |
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| 321 | public boolean booleanValueOf(Object node) throws JaxenException |
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| 322 | { |
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| 323 | 24 | Context context = getContext( node ); |
| 324 | 24 | List result = selectNodesForContext( context ); |
| 325 | 24 | if ( result == null ) return false; |
| 326 | 24 | return BooleanFunction.evaluate( result, context.getNavigator() ).booleanValue(); |
| 327 | } |
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| 328 | ||
| 329 | /** Retrieve a number-value interpretation of this XPath |
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| 330 | * expression when evaluated against a given context. |
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| 331 | * |
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| 332 | * <p> |
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| 333 | * The number-value of the expression is determined per |
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| 334 | * the <code>number(..)</code> core function as defined |
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| 335 | * in the XPath specification. This means that if this |
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| 336 | * expression selects multiple nodes, the number-value |
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| 337 | * of the first node is returned. |
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| 338 | * </p> |
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| 339 | * |
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| 340 | * @param node the node, node-set or Context object for evaluation. This value can be null. |
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| 341 | * |
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| 342 | * @return a <code>Double</code> indicating the numeric value of |
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| 343 | * evaluating this expression against the specified context |
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| 344 | * @throws JaxenException if an XPath error occurs during expression evaluation |
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| 345 | */ |
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| 346 | public Number numberValueOf(Object node) throws JaxenException |
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| 347 | { |
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| 348 | 18 | Context context = getContext( node ); |
| 349 | 18 | Object result = selectSingleNodeForContext( context ); |
| 350 | 18 | return NumberFunction.evaluate( result, |
| 351 | context.getNavigator() ); |
|
| 352 | } |
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| 353 | ||
| 354 | // Helpers |
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| 355 | ||
| 356 | /** Add a namespace prefix-to-URI mapping for this XPath |
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| 357 | * expression. |
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| 358 | * |
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| 359 | * <p> |
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| 360 | * Namespace prefix-to-URI mappings in an XPath are independent |
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| 361 | * of those used within any document. Only the mapping explicitly |
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| 362 | * added to this XPath will be available for resolving the |
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| 363 | * XPath expression. |
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| 364 | * </p> |
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| 365 | * |
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| 366 | * <p> |
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| 367 | * This is a convenience method for adding mappings to the |
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| 368 | * default {@link NamespaceContext} in place for this XPath. |
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| 369 | * If you have installed a custom <code>NamespaceContext</code> |
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| 370 | * that is not a <code>SimpleNamespaceContext</code>, |
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| 371 | * then this method will throw a <code>JaxenException</code>. |
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| 372 | * </p> |
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| 373 | * |
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| 374 | * @param prefix the namespace prefix |
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| 375 | * @param uri the namespace URI |
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| 376 | * |
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| 377 | * @throws JaxenException if the <code>NamespaceContext</code> |
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| 378 | * used by this XPath is not a <code>SimpleNamespaceContext</code> |
|
| 379 | */ |
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| 380 | public void addNamespace(String prefix, |
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| 381 | String uri) throws JaxenException |
|
| 382 | { |
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| 383 | 18 | NamespaceContext nsContext = getNamespaceContext(); |
| 384 | 18 | if ( nsContext instanceof SimpleNamespaceContext ) |
| 385 | { |
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| 386 | 12 | ((SimpleNamespaceContext)nsContext).addNamespace( prefix, |
| 387 | uri ); |
|
| 388 | 12 | return; |
| 389 | } |
|
| 390 | ||
| 391 | 6 | throw new JaxenException("Operation not permitted while using a non-simple namespace context."); |
| 392 | } |
|
| 393 | ||
| 394 | ||
| 395 | // ------------------------------------------------------------ |
|
| 396 | // ------------------------------------------------------------ |
|
| 397 | // Properties |
|
| 398 | // ------------------------------------------------------------ |
|
| 399 | // ------------------------------------------------------------ |
|
| 400 | ||
| 401 | ||
| 402 | /** Set a <code>NamespaceContext</code> for use with this |
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| 403 | * XPath expression. |
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| 404 | * |
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| 405 | * <p> |
|
| 406 | * A <code>NamespaceContext</code> is responsible for translating |
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| 407 | * namespace prefixes within the expression into namespace URIs. |
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| 408 | * </p> |
|
| 409 | * |
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| 410 | * @param namespaceContext the <code>NamespaceContext</code> to |
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| 411 | * install for this expression |
|
| 412 | * |
|
| 413 | * @see NamespaceContext |
|
| 414 | * @see NamespaceContext#translateNamespacePrefixToUri |
|
| 415 | */ |
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| 416 | public void setNamespaceContext(NamespaceContext namespaceContext) |
|
| 417 | { |
|
| 418 | 192 | getContextSupport().setNamespaceContext(namespaceContext); |
| 419 | 192 | } |
| 420 | ||
| 421 | /** Set a <code>FunctionContext</code> for use with this XPath |
|
| 422 | * expression. |
|
| 423 | * |
|
| 424 | * <p> |
|
| 425 | * A <code>FunctionContext</code> is responsible for resolving |
|
| 426 | * all function calls used within the expression. |
|
| 427 | * </p> |
|
| 428 | * |
|
| 429 | * @param functionContext the <code>FunctionContext</code> to |
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| 430 | * install for this expression |
|
| 431 | * |
|
| 432 | * @see FunctionContext |
|
| 433 | * @see FunctionContext#getFunction |
|
| 434 | */ |
|
| 435 | public void setFunctionContext(FunctionContext functionContext) |
|
| 436 | { |
|
| 437 | 174 | getContextSupport().setFunctionContext(functionContext); |
| 438 | 174 | } |
| 439 | ||
| 440 | /** Set a <code>VariableContext</code> for use with this XPath |
|
| 441 | * expression. |
|
| 442 | * |
|
| 443 | * <p> |
|
| 444 | * A <code>VariableContext</code> is responsible for resolving |
|
| 445 | * all variables referenced within the expression. |
|
| 446 | * </p> |
|
| 447 | * |
|
| 448 | * @param variableContext The <code>VariableContext</code> to |
|
| 449 | * install for this expression |
|
| 450 | * |
|
| 451 | * @see VariableContext |
|
| 452 | * @see VariableContext#getVariableValue |
|
| 453 | */ |
|
| 454 | public void setVariableContext(VariableContext variableContext) |
|
| 455 | { |
|
| 456 | 168 | getContextSupport().setVariableContext(variableContext); |
| 457 | 168 | } |
| 458 | ||
| 459 | /** Retrieve the <code>NamespaceContext</code> used by this XPath |
|
| 460 | * expression. |
|
| 461 | * |
|
| 462 | * <p> |
|
| 463 | * A <code>NamespaceContext</code> is responsible for mapping |
|
| 464 | * prefixes used within the expression to namespace URIs. |
|
| 465 | * </p> |
|
| 466 | * |
|
| 467 | * <p> |
|
| 468 | * If this XPath expression has not previously had a <code>NamespaceContext</code> |
|
| 469 | * installed, a new default <code>NamespaceContext</code> will be created, |
|
| 470 | * installed and returned. |
|
| 471 | * </p> |
|
| 472 | * |
|
| 473 | * @return the <code>NamespaceContext</code> used by this expression |
|
| 474 | * |
|
| 475 | * @see NamespaceContext |
|
| 476 | */ |
|
| 477 | public NamespaceContext getNamespaceContext() |
|
| 478 | { |
|
| 479 | 24 | return getContextSupport().getNamespaceContext(); |
| 480 | } |
|
| 481 | ||
| 482 | /** Retrieve the <code>FunctionContext</code> used by this XPath |
|
| 483 | * expression. |
|
| 484 | * |
|
| 485 | * <p> |
|
| 486 | * A <code>FunctionContext</code> is responsible for resolving |
|
| 487 | * all function calls used within the expression. |
|
| 488 | * </p> |
|
| 489 | * |
|
| 490 | * <p> |
|
| 491 | * If this XPath expression has not previously had a <code>FunctionContext</code> |
|
| 492 | * installed, a new default <code>FunctionContext</code> will be created, |
|
| 493 | * installed and returned. |
|
| 494 | * </p> |
|
| 495 | * |
|
| 496 | * @return the <code>FunctionContext</code> used by this expression |
|
| 497 | * |
|
| 498 | * @see FunctionContext |
|
| 499 | */ |
|
| 500 | public FunctionContext getFunctionContext() |
|
| 501 | { |
|
| 502 | 12 | return getContextSupport().getFunctionContext(); |
| 503 | } |
|
| 504 | ||
| 505 | /** Retrieve the <code>VariableContext</code> used by this XPath |
|
| 506 | * expression. |
|
| 507 | * |
|
| 508 | * <p> |
|
| 509 | * A <code>VariableContext</code> is responsible for resolving |
|
| 510 | * all variables referenced within the expression. |
|
| 511 | * </p> |
|
| 512 | * |
|
| 513 | * <p> |
|
| 514 | * If this XPath expression has not previously had a <code>VariableContext</code> |
|
| 515 | * installed, a new default <code>VariableContext</code> will be created, |
|
| 516 | * installed and returned. |
|
| 517 | * </p> |
|
| 518 | * |
|
| 519 | * @return the <code>VariableContext</code> used by this expression |
|
| 520 | * |
|
| 521 | * @see VariableContext |
|
| 522 | */ |
|
| 523 | public VariableContext getVariableContext() |
|
| 524 | { |
|
| 525 | 6 | return getContextSupport().getVariableContext(); |
| 526 | } |
|
| 527 | ||
| 528 | ||
| 529 | /** Retrieve the root expression of the internal |
|
| 530 | * compiled form of this XPath expression. |
|
| 531 | * |
|
| 532 | * <p> |
|
| 533 | * Internally, Jaxen maintains a form of Abstract Syntax |
|
| 534 | * Tree (AST) to represent the structure of the XPath expression. |
|
| 535 | * This is normally not required during normal consumer-grade |
|
| 536 | * usage of Jaxen. This method is provided for hard-core users |
|
| 537 | * who wish to manipulate or inspect a tree-based version of |
|
| 538 | * the expression. |
|
| 539 | * </p> |
|
| 540 | * |
|
| 541 | * @return the root of the AST of this expression |
|
| 542 | */ |
|
| 543 | public Expr getRootExpr() |
|
| 544 | { |
|
| 545 | 6 | return xpath.getRootExpr(); |
| 546 | } |
|
| 547 | ||
| 548 | /** Return the original expression text. |
|
| 549 | * |
|
| 550 | * @return the normalized XPath expression string |
|
| 551 | */ |
|
| 552 | public String toString() |
|
| 553 | { |
|
| 554 | 1488 | return this.exprText; |
| 555 | } |
|
| 556 | ||
| 557 | /** Returns a string representation of the parse tree. |
|
| 558 | * |
|
| 559 | * @return a string representation of the parse tree. |
|
| 560 | */ |
|
| 561 | public String debug() |
|
| 562 | { |
|
| 563 | 6 | return this.xpath.toString(); |
| 564 | } |
|
| 565 | ||
| 566 | // ------------------------------------------------------------ |
|
| 567 | // ------------------------------------------------------------ |
|
| 568 | // Implementation methods |
|
| 569 | // ------------------------------------------------------------ |
|
| 570 | // ------------------------------------------------------------ |
|
| 571 | ||
| 572 | ||
| 573 | /** Create a {@link Context} wrapper for the provided |
|
| 574 | * implementation-specific object. |
|
| 575 | * |
|
| 576 | * @param node the implementation-specific object |
|
| 577 | * to be used as the context |
|
| 578 | * |
|
| 579 | * @return a <code>Context</code> wrapper around the object |
|
| 580 | */ |
|
| 581 | protected Context getContext(Object node) |
|
| 582 | { |
|
| 583 | 10296 | if ( node instanceof Context ) |
| 584 | { |
|
| 585 | 7032 | return (Context) node; |
| 586 | } |
|
| 587 | ||
| 588 | 3264 | Context fullContext = new Context( getContextSupport() ); |
| 589 | ||
| 590 | 3264 | if ( node instanceof List ) |
| 591 | { |
|
| 592 | 6 | fullContext.setNodeSet( (List) node ); |
| 593 | } |
|
| 594 | else |
|
| 595 | { |
|
| 596 | 3258 | List list = new SingletonList(node); |
| 597 | 3258 | fullContext.setNodeSet( list ); |
| 598 | } |
|
| 599 | ||
| 600 | 3264 | return fullContext; |
| 601 | } |
|
| 602 | ||
| 603 | /** Retrieve the {@link ContextSupport} aggregation of |
|
| 604 | * <code>NamespaceContext</code>, <code>FunctionContext</code>, |
|
| 605 | * <code>VariableContext</code>, and {@link Navigator}. |
|
| 606 | * |
|
| 607 | * @return aggregate <code>ContextSupport</code> for this |
|
| 608 | * XPath expression |
|
| 609 | */ |
|
| 610 | protected ContextSupport getContextSupport() |
|
| 611 | { |
|
| 612 | 3840 | if ( support == null ) |
| 613 | { |
|
| 614 | 3450 | support = new ContextSupport( |
| 615 | createNamespaceContext(), |
|
| 616 | createFunctionContext(), |
|
| 617 | createVariableContext(), |
|
| 618 | getNavigator() |
|
| 619 | ); |
|
| 620 | } |
|
| 621 | ||
| 622 | 3840 | return support; |
| 623 | } |
|
| 624 | ||
| 625 | /** Retrieve the XML object-model-specific {@link Navigator} |
|
| 626 | * for us in evaluating this XPath expression. |
|
| 627 | * |
|
| 628 | * @return the implementation-specific <code>Navigator</code> |
|
| 629 | */ |
|
| 630 | public Navigator getNavigator() |
|
| 631 | { |
|
| 632 | 3456 | return navigator; |
| 633 | } |
|
| 634 | ||
| 635 | ||
| 636 | ||
| 637 | // ------------------------------------------------------------ |
|
| 638 | // ------------------------------------------------------------ |
|
| 639 | // Factory methods for default contexts |
|
| 640 | // ------------------------------------------------------------ |
|
| 641 | // ------------------------------------------------------------ |
|
| 642 | ||
| 643 | /** Create a default <code>FunctionContext</code>. |
|
| 644 | * |
|
| 645 | * @return a default <code>FunctionContext</code> |
|
| 646 | */ |
|
| 647 | protected FunctionContext createFunctionContext() |
|
| 648 | { |
|
| 649 | 3450 | return XPathFunctionContext.getInstance(); |
| 650 | } |
|
| 651 | ||
| 652 | /** Create a default <code>NamespaceContext</code>. |
|
| 653 | * |
|
| 654 | * @return a default <code>NamespaceContext</code> instance |
|
| 655 | */ |
|
| 656 | protected NamespaceContext createNamespaceContext() |
|
| 657 | { |
|
| 658 | 3450 | return new SimpleNamespaceContext(); |
| 659 | } |
|
| 660 | ||
| 661 | /** Create a default <code>VariableContext</code>. |
|
| 662 | * |
|
| 663 | * @return a default <code>VariableContext</code> instance |
|
| 664 | */ |
|
| 665 | protected VariableContext createVariableContext() |
|
| 666 | { |
|
| 667 | 3450 | return new SimpleVariableContext(); |
| 668 | } |
|
| 669 | ||
| 670 | /** Select all nodes that match this XPath |
|
| 671 | * expression on the given Context object. |
|
| 672 | * If multiple nodes match, multiple nodes |
|
| 673 | * will be returned in document-order, as defined by the XPath |
|
| 674 | * specification. If the expression selects a non-node-set |
|
| 675 | * (i.e. a number, boolean, or string) then a List |
|
| 676 | * containing just that one object is returned. |
|
| 677 | * </p> |
|
| 678 | * |
|
| 679 | * @param context the Context which gets evaluated |
|
| 680 | * |
|
| 681 | * @return the node-set of all items selected |
|
| 682 | * by this XPath expression |
|
| 683 | * @throws JaxenException if an XPath error occurs during expression evaluation |
|
| 684 | * |
|
| 685 | */ |
|
| 686 | protected List selectNodesForContext(Context context) throws JaxenException |
|
| 687 | { |
|
| 688 | 10296 | List list = this.xpath.asList( context ); |
| 689 | 9930 | return list; |
| 690 | ||
| 691 | } |
|
| 692 | ||
| 693 | ||
| 694 | /** Return only the first node that is selected by this XPath |
|
| 695 | * expression. If multiple nodes match, only one node will be |
|
| 696 | * returned. The selected node will be the first |
|
| 697 | * selected node in document-order, as defined by the XPath |
|
| 698 | * specification. If the XPath expression selects a double, |
|
| 699 | * String, or boolean, then that object is returned. |
|
| 700 | * </p> |
|
| 701 | * |
|
| 702 | * @param context the Context against which this expression is evaluated |
|
| 703 | * |
|
| 704 | * @return the first node in document order of all nodes selected |
|
| 705 | * by this XPath expression |
|
| 706 | * @throws JaxenException if an XPath error occurs during expression evaluation |
|
| 707 | * |
|
| 708 | * @see #selectNodesForContext |
|
| 709 | */ |
|
| 710 | protected Object selectSingleNodeForContext(Context context) throws JaxenException |
|
| 711 | { |
|
| 712 | 36 | List results = selectNodesForContext( context ); |
| 713 | ||
| 714 | 36 | if ( results.isEmpty() ) |
| 715 | { |
|
| 716 | 12 | return null; |
| 717 | } |
|
| 718 | ||
| 719 | 24 | return results.get( 0 ); |
| 720 | } |
|
| 721 | ||
| 722 | } |