1 /* 2 * Copyright (c) 2003, 2005, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.xml.xpath; 27 28 import org.xml.sax.InputSource; 29 import javax.xml.namespace.QName; 30 import javax.xml.namespace.NamespaceContext; 31 32 /** 33 * <p><code>XPath</code> provides access to the XPath evaluation environment and expressions.</p> 34 * 35 * <a name="XPath-evaluation"/> 36 * <table border="1" cellpadding="2"> 37 * <thead> 38 * <tr> 39 * <th colspan="2">Evaluation of XPath Expressions.</th> 40 * </tr> 41 * </thead> 42 * <tbody> 43 * <tr> 44 * <td>context</td> 45 * <td> 46 * If a request is made to evaluate the expression in the absence 47 * of a context item, an empty document node will be used for the context. 48 * For the purposes of evaluating XPath expressions, a DocumentFragment 49 * is treated like a Document node. 50 * </td> 51 * </tr> 52 * <tr> 53 * <td>variables</td> 54 * <td> 55 * If the expression contains a variable reference, its value will be found through the {@link XPathVariableResolver} 56 * set with {@link #setXPathVariableResolver(XPathVariableResolver resolver)}. 57 * An {@link XPathExpressionException} is raised if the variable resolver is undefined or 58 * the resolver returns <code>null</code> for the variable. 59 * The value of a variable must be immutable through the course of any single evaluation.</p> 60 * </td> 61 * </tr> 62 * <tr> 63 * <td>functions</td> 64 * <td> 65 * If the expression contains a function reference, the function will be found through the {@link XPathFunctionResolver} 66 * set with {@link #setXPathFunctionResolver(XPathFunctionResolver resolver)}. 67 * An {@link XPathExpressionException} is raised if the function resolver is undefined or 68 * the function resolver returns <code>null</code> for the function.</p> 69 * </td> 70 * </tr> 71 * <tr> 72 * <td>QNames</td> 73 * <td> 74 * QNames in the expression are resolved against the XPath namespace context 75 * set with {@link #setNamespaceContext(NamespaceContext nsContext)}. 76 * </td> 77 * </tr> 78 * <tr> 79 * <td>result</td> 80 * <td> 81 * This result of evaluating an expression is converted to an instance of the desired return type. 82 * Valid return types are defined in {@link XPathConstants}. 83 * Conversion to the return type follows XPath conversion rules.</p> 84 * </td> 85 * </tr> 86 * </table> 87 * 88 * <p>An XPath object is not thread-safe and not reentrant. 89 * In other words, it is the application's responsibility to make 90 * sure that one {@link XPath} object is not used from 91 * more than one thread at any given time, and while the <code>evaluate</code> 92 * method is invoked, applications may not recursively call 93 * the <code>evaluate</code> method. 94 * <p> 95 * 96 * @author <a href="Norman.Walsh@Sun.com">Norman Walsh</a> 97 * @author <a href="Jeff.Suttor@Sun.com">Jeff Suttor</a> 98 * @see <a href="http://www.w3.org/TR/xpath">XML Path Language (XPath) Version 1.0</a> 99 * @since 1.5 100 */ 101 public interface XPath { 102 103 /** 104 * <p>Reset this <code>XPath</code> to its original configuration.</p> 105 * 106 * <p><code>XPath</code> is reset to the same state as when it was created with 107 * {@link XPathFactory#newXPath()}. 108 * <code>reset()</code> is designed to allow the reuse of existing <code>XPath</code>s 109 * thus saving resources associated with the creation of new <code>XPath</code>s.</p> 110 * 111 * <p>The reset <code>XPath</code> is not guaranteed to have the same {@link XPathFunctionResolver}, {@link XPathVariableResolver} 112 * or {@link NamespaceContext} <code>Object</code>s, e.g. {@link Object#equals(Object obj)}. 113 * It is guaranteed to have a functionally equal <code>XPathFunctionResolver</code>, <code>XPathVariableResolver</code> 114 * and <code>NamespaceContext</code>.</p> 115 */ 116 public void reset(); 117 118 /** 119 * <p>Establish a variable resolver.</p> 120 * 121 * <p>A <code>NullPointerException</code> is thrown if <code>resolver</code> is <code>null</code>.</p> 122 * 123 * @param resolver Variable resolver. 124 * 125 * @throws NullPointerException If <code>resolver</code> is <code>null</code>. 126 */ 127 public void setXPathVariableResolver(XPathVariableResolver resolver); 128 129 /** 130 * <p>Return the current variable resolver.</p> 131 * 132 * <p><code>null</code> is returned in no variable resolver is in effect.</p> 133 * 134 * @return Current variable resolver. 135 */ 136 public XPathVariableResolver getXPathVariableResolver(); 137 138 /** 139 * <p>Establish a function resolver.</p> 140 * 141 * <p>A <code>NullPointerException</code> is thrown if <code>resolver</code> is <code>null</code>.</p> 142 * 143 * @param resolver XPath function resolver. 144 * 145 * @throws NullPointerException If <code>resolver</code> is <code>null</code>. 146 */ 147 public void setXPathFunctionResolver(XPathFunctionResolver resolver); 148 149 /** 150 * <p>Return the current function resolver.</p> 151 * 152 * <p><code>null</code> is returned in no function resolver is in effect.</p> 153 * 154 * @return Current function resolver. 155 */ 156 public XPathFunctionResolver getXPathFunctionResolver(); 157 158 /** 159 * <p>Establish a namespace context.</p> 160 * 161 * <p>A <code>NullPointerException</code> is thrown if <code>nsContext</code> is <code>null</code>.</p> 162 * 163 * @param nsContext Namespace context to use. 164 * 165 * @throws NullPointerException If <code>nsContext</code> is <code>null</code>. 166 */ 167 public void setNamespaceContext(NamespaceContext nsContext); 168 169 /** 170 * <p>Return the current namespace context.</p> 171 * 172 * <p><code>null</code> is returned in no namespace context is in effect.</p> 173 * 174 * @return Current Namespace context. 175 */ 176 public NamespaceContext getNamespaceContext(); 177 178 /** 179 * <p>Compile an XPath expression for later evaluation.</p> 180 * 181 * <p>If <code>expression</code> contains any {@link XPathFunction}s, 182 * they must be available via the {@link XPathFunctionResolver}. 183 * An {@link XPathExpressionException} will be thrown if the 184 * <code>XPathFunction</code> 185 * cannot be resovled with the <code>XPathFunctionResolver</code>.</p> 186 * 187 * <p>If <code>expression</code> contains any variables, the 188 * {@link XPathVariableResolver} in effect 189 * <strong>at compile time</strong> will be used to resolve them.</p> 190 * 191 * <p>If <code>expression</code> is <code>null</code>, a <code>NullPointerException</code> is thrown.</p> 192 * 193 * @param expression The XPath expression. 194 * 195 * @return Compiled XPath expression. 196 197 * @throws XPathExpressionException If <code>expression</code> cannot be compiled. 198 * @throws NullPointerException If <code>expression</code> is <code>null</code>. 199 */ 200 public XPathExpression compile(String expression) 201 throws XPathExpressionException; 202 203 /** 204 * <p>Evaluate an <code>XPath</code> expression in the specified context and return the result as the specified type.</p> 205 * 206 * <p>See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, 207 * variable, function and <code>QName</code> resolution and return type conversion.</p> 208 * 209 * <p>If <code>returnType</code> is not one of the types defined in {@link XPathConstants} ( 210 * {@link XPathConstants#NUMBER NUMBER}, 211 * {@link XPathConstants#STRING STRING}, 212 * {@link XPathConstants#BOOLEAN BOOLEAN}, 213 * {@link XPathConstants#NODE NODE} or 214 * {@link XPathConstants#NODESET NODESET}) 215 * then an <code>IllegalArgumentException</code> is thrown.</p> 216 * 217 * <p>If a <code>null</code> value is provided for 218 * <code>item</code>, an empty document will be used for the 219 * context. 220 * If <code>expression</code> or <code>returnType</code> is <code>null</code>, then a 221 * <code>NullPointerException</code> is thrown.</p> 222 * 223 * @param expression The XPath expression. 224 * @param item The starting context (a node, for example). 225 * @param returnType The desired return type. 226 * 227 * @return Result of evaluating an XPath expression as an <code>Object</code> of <code>returnType</code>. 228 * 229 * @throws XPathExpressionException If <code>expression</code> cannot be evaluated. 230 * @throws IllegalArgumentException If <code>returnType</code> is not one of the types defined in {@link XPathConstants}. 231 * @throws NullPointerException If <code>expression</code> or <code>returnType</code> is <code>null</code>. 232 */ 233 public Object evaluate(String expression, Object item, QName returnType) 234 throws XPathExpressionException; 235 236 /** 237 * <p>Evaluate an XPath expression in the specified context and return the result as a <code>String</code>.</p> 238 * 239 * <p>This method calls {@link #evaluate(String expression, Object item, QName returnType)} with a <code>returnType</code> of 240 * {@link XPathConstants#STRING}.</p> 241 * 242 * <p>See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, 243 * variable, function and QName resolution and return type conversion.</p> 244 * 245 * <p>If a <code>null</code> value is provided for 246 * <code>item</code>, an empty document will be used for the 247 * context. 248 * If <code>expression</code> is <code>null</code>, then a <code>NullPointerException</code> is thrown.</p> 249 * 250 * @param expression The XPath expression. 251 * @param item The starting context (a node, for example). 252 * 253 * @return The <code>String</code> that is the result of evaluating the expression and 254 * converting the result to a <code>String</code>. 255 * 256 * @throws XPathExpressionException If <code>expression</code> cannot be evaluated. 257 * @throws NullPointerException If <code>expression</code> is <code>null</code>. 258 */ 259 public String evaluate(String expression, Object item) 260 throws XPathExpressionException; 261 262 /** 263 * <p>Evaluate an XPath expression in the context of the specified <code>InputSource</code> 264 * and return the result as the specified type.</p> 265 * 266 * <p>This method builds a data model for the {@link InputSource} and calls 267 * {@link #evaluate(String expression, Object item, QName returnType)} on the resulting document object.</p> 268 * 269 * <p>See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, 270 * variable, function and QName resolution and return type conversion.</p> 271 * 272 * <p>If <code>returnType</code> is not one of the types defined in {@link XPathConstants}, 273 * then an <code>IllegalArgumentException</code> is thrown.</p> 274 * 275 * <p>If <code>expression</code>, <code>source</code> or <code>returnType</code> is <code>null</code>, 276 * then a <code>NullPointerException</code> is thrown.</p> 277 * 278 * @param expression The XPath expression. 279 * @param source The input source of the document to evaluate over. 280 * @param returnType The desired return type. 281 * 282 * @return The <code>Object</code> that encapsulates the result of evaluating the expression. 283 * 284 * @throws XPathExpressionException If expression cannot be evaluated. 285 * @throws IllegalArgumentException If <code>returnType</code> is not one of the types defined in {@link XPathConstants}. 286 * @throws NullPointerException If <code>expression</code>, <code>source</code> or <code>returnType</code> 287 * is <code>null</code>. 288 */ 289 public Object evaluate( 290 String expression, 291 InputSource source, 292 QName returnType) 293 throws XPathExpressionException; 294 295 /** 296 * <p>Evaluate an XPath expression in the context of the specified <code>InputSource</code> 297 * and return the result as a <code>String</code>.</p> 298 * 299 * <p>This method calls {@link #evaluate(String expression, InputSource source, QName returnType)} with a 300 * <code>returnType</code> of {@link XPathConstants#STRING}.</p> 301 * 302 * <p>See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, 303 * variable, function and QName resolution and return type conversion.</p> 304 * 305 * <p>If <code>expression</code> or <code>source</code> is <code>null</code>, 306 * then a <code>NullPointerException</code> is thrown.</p> 307 * 308 * @param expression The XPath expression. 309 * @param source The <code>InputSource</code> of the document to evaluate over. 310 * 311 * @return The <code>String</code> that is the result of evaluating the expression and 312 * converting the result to a <code>String</code>. 313 * 314 * @throws XPathExpressionException If expression cannot be evaluated. 315 * @throws NullPointerException If <code>expression</code> or <code>source</code> is <code>null</code>. 316 */ 317 public String evaluate(String expression, InputSource source) 318 throws XPathExpressionException; 319 } | 1 /* 2 * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.xml.xpath; 27 28 import javax.xml.namespace.NamespaceContext; 29 import javax.xml.namespace.QName; 30 import org.xml.sax.InputSource; 31 32 /** 33 * {@code XPath} provides access to the XPath evaluation environment and expressions. 34 * 35 * <a name="XPath-evaluation"/> 36 * <table border="1" cellpadding="2"> 37 * <thead> 38 * <tr> 39 * <th colspan="2">Evaluation of XPath Expressions.</th> 40 * </tr> 41 * </thead> 42 * <tr> 43 * <td>context</td> 44 * <td> 45 * If a request is made to evaluate the expression in the absence 46 * of a context item, an empty document node will be used for the context. 47 * For the purposes of evaluating XPath expressions, a DocumentFragment 48 * is treated like a Document node. 49 * </td> 50 * </tr> 51 * <tr> 52 * <td>variables</td> 53 * <td> 54 * If the expression contains a variable reference, its value will be found through the {@link XPathVariableResolver} 55 * set with {@link #setXPathVariableResolver(XPathVariableResolver resolver)}. 56 * An {@link XPathExpressionException} is raised if the variable resolver is undefined or 57 * the resolver returns {@code null} for the variable. 58 * The value of a variable must be immutable through the course of any single evaluation. 59 * </td> 60 * </tr> 61 * <tr> 62 * <td>functions</td> 63 * <td> 64 * If the expression contains a function reference, the function will be found through the {@link XPathFunctionResolver} 65 * set with {@link #setXPathFunctionResolver(XPathFunctionResolver resolver)}. 66 * An {@link XPathExpressionException} is raised if the function resolver is undefined or 67 * the function resolver returns {@code null} for the function. 68 * </td> 69 * </tr> 70 * <tr> 71 * <td>QNames</td> 72 * <td> 73 * QNames in the expression are resolved against the XPath namespace context 74 * set with {@link #setNamespaceContext(NamespaceContext nsContext)}. 75 * </td> 76 * </tr> 77 * <tr> 78 * <td>result</td> 79 * <td> 80 * This result of evaluating an expression is converted to an instance of the desired return type. 81 * Valid return types are defined in {@link XPathConstants}. 82 * Conversion to the return type follows XPath conversion rules. 83 * </td> 84 * </tr> 85 * </table> 86 * 87 * <p>An XPath object is not thread-safe and not reentrant. 88 * In other words, it is the application's responsibility to make 89 * sure that one {@link XPath} object is not used from 90 * more than one thread at any given time, and while the {@code evaluate} 91 * method is invoked, applications may not recursively call 92 * the {@code evaluate} method. 93 * <p> 94 * 95 * @author <a href="Norman.Walsh@Sun.com">Norman Walsh</a> 96 * @author <a href="Jeff.Suttor@Sun.com">Jeff Suttor</a> 97 * @see <a href="http://www.w3.org/TR/xpath">XML Path Language (XPath) Version 1.0</a> 98 * @since 1.5 99 */ 100 public interface XPath { 101 102 103 /** 104 * Reset this {@code XPath} to its original configuration. 105 * 106 * <p>{@code XPath} is reset to the same state as when it was created with 107 * {@link XPathFactory#newXPath()}. 108 * {@code reset()} is designed to allow the reuse of existing {@code XPath}s 109 * thus saving resources associated with the creation of new {@code XPath}s. 110 * 111 * <p>The reset {@code XPath} is not guaranteed to have the same 112 * {@link XPathFunctionResolver}, {@link XPathVariableResolver} 113 * or {@link NamespaceContext} {@code Object}s, e.g. {@link Object#equals(Object obj)}. 114 * It is guaranteed to have a functionally equal {@code XPathFunctionResolver}, 115 * {@code XPathVariableResolver} and {@code NamespaceContext}. 116 */ 117 public void reset(); 118 119 /** 120 * Establish a variable resolver. 121 * 122 * <p>A {@code NullPointerException} is thrown if {@code resolver} is {@code null}. 123 * 124 * @param resolver Variable resolver. 125 * 126 * @throws NullPointerException If {@code resolver} is {@code null}. 127 */ 128 public void setXPathVariableResolver(XPathVariableResolver resolver); 129 130 /** 131 * Return the current variable resolver. 132 * 133 * <p>{@code null} is returned in no variable resolver is in effect. 134 * 135 * @return Current variable resolver. 136 */ 137 public XPathVariableResolver getXPathVariableResolver(); 138 139 /** 140 * Establish a function resolver. 141 * 142 * <p>A {@code NullPointerException} is thrown if {@code resolver} is {@code null}. 143 * 144 * @param resolver XPath function resolver. 145 * 146 * @throws NullPointerException If {@code resolver} is {@code null}. 147 */ 148 public void setXPathFunctionResolver(XPathFunctionResolver resolver); 149 150 /** 151 * Return the current function resolver. 152 * <p> 153 * {@code null} is returned in no function resolver is in effect. 154 * 155 * @return Current function resolver. 156 */ 157 public XPathFunctionResolver getXPathFunctionResolver(); 158 159 /** 160 * Establish a namespace context. 161 * 162 * <p>A {@code NullPointerException} is thrown if {@code nsContext} is {@code null}. 163 * 164 * @param nsContext Namespace context to use. 165 * 166 * @throws NullPointerException If {@code nsContext} is {@code null}. 167 */ 168 public void setNamespaceContext(NamespaceContext nsContext); 169 170 /** 171 * Return the current namespace context. 172 * 173 * <p>{@code null} is returned in no namespace context is in effect. 174 * 175 * @return Current Namespace context. 176 */ 177 public NamespaceContext getNamespaceContext(); 178 179 /** 180 * Compile an XPath expression for later evaluation. 181 * 182 * <p>If {@code expression} contains any {@link XPathFunction}s, 183 * they must be available via the {@link XPathFunctionResolver}. 184 * An {@link XPathExpressionException} will be thrown if the 185 * {@code XPathFunction} 186 * cannot be resovled with the {@code XPathFunctionResolver}. 187 * 188 * <p>If {@code expression} contains any variables, the 189 * {@link XPathVariableResolver} in effect 190 * <strong>at compile time</strong> will be used to resolve them. 191 * 192 * @param expression The XPath expression. 193 * 194 * @return Compiled XPath expression. 195 196 * @throws XPathExpressionException If {@code expression} cannot be compiled. 197 * @throws NullPointerException If {@code expression} is {@code null}. 198 */ 199 public XPathExpression compile(String expression) 200 throws XPathExpressionException; 201 202 /** 203 * Evaluate an {@code XPath} expression in the specified context and 204 * return the result as the specified type. 205 * 206 * <p> 207 * See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> 208 * for context item evaluation, variable, function and {@code QName} resolution 209 * and return type conversion. 210 * <p> 211 * The parameter {@code item} represents the context the XPath expression 212 * will be operated on. The type of the context is implementation-dependent. 213 * If the value is {@code null}, the operation must have no dependency on 214 * the context, otherwise an XPathExpressionException will be thrown. 215 * 216 * @implNote 217 * The type of the context is usually {@link org.w3c.dom.Node}. 218 * 219 * @param expression The XPath expression. 220 * @param item The context the XPath expression will be evaluated in. 221 * @param returnType The result type expected to be returned by the XPath expression. 222 * 223 * @return The result of evaluating an XPath expression as an {@code Object} of {@code returnType}. 224 * 225 * @throws XPathExpressionException If {@code expression} cannot be evaluated. 226 * @throws IllegalArgumentException If {@code returnType} is not one of the types defined in {@link XPathConstants} ( 227 * {@link XPathConstants#NUMBER NUMBER}, 228 * {@link XPathConstants#STRING STRING}, 229 * {@link XPathConstants#BOOLEAN BOOLEAN}, 230 * {@link XPathConstants#NODE NODE} or 231 * {@link XPathConstants#NODESET NODESET}). 232 * @throws NullPointerException If {@code expression or returnType} is {@code null}. 233 */ 234 public Object evaluate(String expression, Object item, QName returnType) 235 throws XPathExpressionException; 236 237 /** 238 * Evaluate an XPath expression in the specified context and return the result as a {@code String}. 239 * 240 * <p>This method calls {@link #evaluate(String expression, Object item, QName returnType)} with a {@code returnType} of 241 * {@link XPathConstants#STRING}. 242 * 243 * <p>See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, 244 * variable, function and QName resolution and return type conversion. 245 * 246 * <p> 247 * The parameter {@code item} represents the context the XPath expression 248 * will be operated on. The type of the context is implementation-dependent. 249 * If the value is {@code null}, the operation must have no dependency on 250 * the context, otherwise an XPathExpressionException will be thrown. 251 * 252 * @implNote 253 * The type of the context is usually {@link org.w3c.dom.Node}. 254 * 255 * @param expression The XPath expression. 256 * @param item The context the XPath expression will be evaluated in. 257 * 258 * @return The result of evaluating an XPath expression as a {@code String}. 259 * 260 * @throws XPathExpressionException If {@code expression} cannot be evaluated. 261 * @throws NullPointerException If {@code expression} is {@code null}. 262 */ 263 public String evaluate(String expression, Object item) 264 throws XPathExpressionException; 265 266 /** 267 * Evaluate an XPath expression in the context of the specified {@code InputSource} 268 * and return the result as the specified type. 269 * 270 * <p>This method builds a data model for the {@link InputSource} and calls 271 * {@link #evaluate(String expression, Object item, QName returnType)} on the resulting document object. 272 * 273 * <p>See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, 274 * variable, function and QName resolution and return type conversion. 275 * 276 * @param expression The XPath expression. 277 * @param source The input source of the document to evaluate over. 278 * @param returnType The desired return type. 279 * 280 * @return The {@code Object} that encapsulates the result of evaluating the expression. 281 * 282 * @throws XPathExpressionException If expression cannot be evaluated. 283 * @throws IllegalArgumentException If {@code returnType} is not one of the types defined in {@link XPathConstants}. 284 * @throws NullPointerException If {@code expression, source or returnType} is {@code null}. 285 */ 286 public Object evaluate( 287 String expression, 288 InputSource source, 289 QName returnType) 290 throws XPathExpressionException; 291 292 /** 293 * Evaluate an XPath expression in the context of the specified {@code InputSource} 294 * and return the result as a {@code String}. 295 * 296 * <p>This method calls {@link #evaluate(String expression, InputSource source, QName returnType)} with a 297 * {@code returnType} of {@link XPathConstants#STRING}. 298 * 299 * <p>See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, 300 * variable, function and QName resolution and return type conversion. 301 * 302 * @param expression The XPath expression. 303 * @param source The {@code InputSource} of the document to evaluate over. 304 * 305 * @return The {@code String} that is the result of evaluating the expression and 306 * converting the result to a {@code String}. 307 * 308 * @throws XPathExpressionException If expression cannot be evaluated. 309 * @throws NullPointerException If {@code expression or source} is {@code null}. 310 */ 311 public String evaluate(String expression, InputSource source) 312 throws XPathExpressionException; 313 314 /** 315 * Evaluate an XPath expression in the specified context and return 316 * the result with the type specified through the {@code class type} 317 * 318 * <p> 319 * The parameter {@code item} represents the context the XPath expression 320 * will be operated on. The type of the context is implementation-dependent. 321 * If the value is {@code null}, the operation must have no dependency on 322 * the context, otherwise an XPathExpressionException will be thrown. 323 * 324 * @implNote 325 * The type of the context is usually {@link org.w3c.dom.Node}. 326 * 327 * @implSpec 328 * The default implementation in the XPath API is equivalent to: 329 * <pre> {@code 330 * (T)evaluate(expression, item, 331 * XPathEvaluationResult.XPathResultType.getQNameType(type)); 332 * }</pre> 333 * 334 * Since the {@code evaluate} method does not support the 335 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type, specifying 336 * XPathEvaluationResult as the type will result in IllegalArgumentException. 337 * Any implementation supporting the 338 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type must override 339 * this method. 340 * 341 * @param <T> The class type that will be returned by the XPath expression. 342 * @param expression The XPath expression. 343 * @param item The context the XPath expression will be evaluated in. 344 * @param type The class type expected to be returned by the XPath expression. 345 * 346 * @return The result of evaluating the expression. 347 * 348 * @throws XPathExpressionException If the expression cannot be evaluated. 349 * @throws IllegalArgumentException If {@code type} is not of the types 350 * corresponding to the types defined in the {@link XPathEvaluationResult.XPathResultType}, 351 * or XPathEvaluationResult is specified as the type but an implementation supporting the 352 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type is not available. 353 * @throws NullPointerException If {@code expression or type} is {@code null}. 354 * 355 * @since 1.9 356 */ 357 default <T>T evaluateExpression(String expression, Object item, Class<T> type) 358 throws XPathExpressionException { 359 return type.cast(evaluate(expression, item, 360 XPathEvaluationResult.XPathResultType.getQNameType(type))); 361 } 362 363 /** 364 * Evaluate an XPath expression in the specified context. This is equivalent to 365 * calling {@link #evaluateExpression(String expression, Object item, Class type)} 366 * with type {@link XPathEvaluationResult}: 367 * <pre> {@code 368 * evaluateExpression(expression, item, XPathEvaluationResult.class); 369 * }</pre> 370 * <p> 371 * The parameter {@code item} represents the context the XPath expression 372 * will be operated on. The type of the context is implementation-dependent. 373 * If the value is {@code null}, the operation must have no dependency on 374 * the context, otherwise an XPathExpressionException will be thrown. 375 * 376 * @implNote 377 * The type of the context is usually {@link org.w3c.dom.Node}. 378 * 379 * @implSpec 380 * The default implementation in the XPath API is equivalent to: 381 * <pre> {@code 382 * evaluateExpression(expression, item, XPathEvaluationResult.class); 383 * }</pre> 384 * 385 * Since the {@code evaluate} method does not support the 386 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} 387 * type, the default implementation of this method will always throw an 388 * IllegalArgumentException. Any implementation supporting the 389 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type must therefore 390 * override this method. 391 * 392 * @param expression The XPath expression. 393 * @param item The context the XPath expression will be evaluated in. 394 * 395 * @return The result of evaluating the expression. 396 * 397 * @throws XPathExpressionException If the expression cannot be evaluated. 398 * @throws IllegalArgumentException If the implementation of this method 399 * does not support the 400 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type. 401 * @throws NullPointerException If {@code expression} is {@code null}. 402 * 403 * @since 1.9 404 */ 405 default XPathEvaluationResult<?> evaluateExpression(String expression, Object item) 406 throws XPathExpressionException 407 { 408 return evaluateExpression(expression, item, XPathEvaluationResult.class); 409 } 410 411 /** 412 * Evaluate an XPath expression in the context of the specified {@code source} 413 * and return the result as specified. 414 * <p> 415 * This method builds a data model for the {@link InputSource} and calls 416 * {@link #evaluateExpression(String expression, Object item, Class type)} 417 * on the resulting document object. The data model is usually 418 * {@link org.w3c.dom.Document} 419 * 420 * @implSpec 421 * The default implementation in the XPath API is equivalent to: 422 * <pre> {@code 423 (T)evaluate(expression, source, 424 XPathEvaluationResult.XPathResultType.getQNameType(type)); 425 * }</pre> 426 * 427 * Since the {@code evaluate} method does not support the 428 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type, specifying 429 * XPathEvaluationResult as the type will result in IllegalArgumentException. 430 * Any implementation supporting the 431 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type must override 432 * this method. 433 * 434 * @param <T> The class type that will be returned by the XPath expression. 435 * @param expression The XPath expression. 436 * @param source The input source of the document to evaluate over. 437 * @param type The class type expected to be returned by the XPath expression. 438 * 439 * @return The result of evaluating the expression. 440 * 441 * @throws XPathExpressionException If the expression cannot be evaluated. 442 * @throws IllegalArgumentException If {@code type} is not of the types 443 * corresponding to the types defined in the {@link XPathEvaluationResult.XPathResultType 444 * XPathResultType}, or XPathEvaluationResult is specified as the type but an 445 * implementation supporting the 446 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type is not available. 447 * @throws NullPointerException If {@code expression, source or type}is {@code null}. 448 * 449 * @since 1.9 450 */ 451 default <T>T evaluateExpression(String expression, InputSource source, Class<T> type) 452 throws XPathExpressionException 453 { 454 return type.cast(evaluate(expression, source, 455 XPathEvaluationResult.XPathResultType.getQNameType(type))); 456 } 457 458 /** 459 * Evaluate an XPath expression in the specified context. This is equivalent to 460 * calling {@link #evaluateExpression(String expression, Object item, Class type)} 461 * with type {@link XPathEvaluationResult}: 462 * <pre> {@code 463 * evaluateExpression(expression, item, XPathEvaluationResult.class); 464 * }</pre> 465 * <p> 466 * 467 * @implSpec 468 * The default implementation in the XPath API is equivalent to: 469 * <pre> {@code 470 * evaluateExpression(expression, source, XPathEvaluationResult.class); 471 * }</pre> 472 * 473 * Since the {@code evaluate} method does not support the 474 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} 475 * type, the default implementation of this method will always throw an 476 * IllegalArgumentException. Any implementation supporting the 477 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type must therefore 478 * override this method. 479 * 480 * @param expression The XPath expression. 481 * @param source The input source of the document to evaluate over. 482 * 483 * @return The result of evaluating the expression. 484 * 485 * @throws XPathExpressionException If the expression cannot be evaluated. 486 * @throws IllegalArgumentException If the implementation of this method 487 * does not support the 488 * {@link XPathEvaluationResult.XPathResultType#ANY ANY} type. 489 * @throws NullPointerException If {@code expression or source} is {@code null}. 490 * 491 * @since 1.9 492 */ 493 default XPathEvaluationResult<?> evaluateExpression(String expression, InputSource source) 494 throws XPathExpressionException 495 { 496 return evaluateExpression(expression, source, XPathEvaluationResult.class); 497 } 498 } |