| /* |
| * Copyright (c) 2003, 2005, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package javax.xml.xpath; |
| |
| import org.xml.sax.InputSource; |
| import javax.xml.namespace.QName; |
| |
| /** |
| * <p><code>XPathExpression</code> provides access to compiled XPath expressions.</p> |
| * |
| * <a name="XPathExpression-evaluation"/> |
| * <table border="1" cellpadding="2"> |
| * <thead> |
| * <tr> |
| * <th colspan="2">Evaluation of XPath Expressions.</th> |
| * </tr> |
| * </thead> |
| * <tbody> |
| * <tr> |
| * <td>context</td> |
| * <td> |
| * If a request is made to evaluate the expression in the absence |
| * of a context item, an empty document node will be used for the context. |
| * For the purposes of evaluating XPath expressions, a DocumentFragment |
| * is treated like a Document node. |
| * </td> |
| * </tr> |
| * <tr> |
| * <td>variables</td> |
| * <td> |
| * If the expression contains a variable reference, its value will be found through the {@link XPathVariableResolver}. |
| * An {@link XPathExpressionException} is raised if the variable resolver is undefined or |
| * the resolver returns <code>null</code> for the variable. |
| * The value of a variable must be immutable through the course of any single evaluation.</p> |
| * </td> |
| * </tr> |
| * <tr> |
| * <td>functions</td> |
| * <td> |
| * If the expression contains a function reference, the function will be found through the {@link XPathFunctionResolver}. |
| * An {@link XPathExpressionException} is raised if the function resolver is undefined or |
| * the function resolver returns <code>null</code> for the function.</p> |
| * </td> |
| * </tr> |
| * <tr> |
| * <td>QNames</td> |
| * <td> |
| * QNames in the expression are resolved against the XPath namespace context. |
| * </td> |
| * </tr> |
| * <tr> |
| * <td>result</td> |
| * <td> |
| * This result of evaluating an expression is converted to an instance of the desired return type. |
| * Valid return types are defined in {@link XPathConstants}. |
| * Conversion to the return type follows XPath conversion rules.</p> |
| * </td> |
| * </tr> |
| * </table> |
| * |
| * <p>An XPath expression is not thread-safe and not reentrant. |
| * In other words, it is the application's responsibility to make |
| * sure that one {@link XPathExpression} object is not used from |
| * more than one thread at any given time, and while the <code>evaluate</code> |
| * method is invoked, applications may not recursively call |
| * the <code>evaluate</code> method. |
| * <p> |
| * |
| * @author <a href="mailto:Norman.Walsh@Sun.com">Norman Walsh</a> |
| * @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a> |
| * @see <a href="http://www.w3.org/TR/xpath#section-Expressions">XML Path Language (XPath) Version 1.0, Expressions</a> |
| * @since 1.5 |
| */ |
| public interface XPathExpression { |
| |
| /** |
| * <p>Evaluate the compiled XPath expression in the specified context and return the result as the specified type.</p> |
| * |
| * <p>See <a href="#XPathExpression-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, |
| * variable, function and QName resolution and return type conversion.</p> |
| * |
| * <p>If <code>returnType</code> is not one of the types defined in {@link XPathConstants}, |
| * then an <code>IllegalArgumentException</code> is thrown.</p> |
| * |
| * <p>If a <code>null</code> value is provided for |
| * <code>item</code>, an empty document will be used for the |
| * context. |
| * If <code>returnType</code> is <code>null</code>, then a <code>NullPointerException</code> is thrown.</p> |
| * |
| * @param item The starting context (a node, for example). |
| * @param returnType The desired return type. |
| * |
| * @return The <code>Object</code> that is the result of evaluating the expression and converting the result to |
| * <code>returnType</code>. |
| * |
| * @throws XPathExpressionException If the expression cannot be evaluated. |
| * @throws IllegalArgumentException If <code>returnType</code> is not one of the types defined in {@link XPathConstants}. |
| * @throws NullPointerException If <code>returnType</code> is <code>null</code>. |
| */ |
| public Object evaluate(Object item, QName returnType) |
| throws XPathExpressionException; |
| |
| /** |
| * <p>Evaluate the compiled XPath expression in the specified context and return the result as a <code>String</code>.</p> |
| * |
| * <p>This method calls {@link #evaluate(Object item, QName returnType)} with a <code>returnType</code> of |
| * {@link XPathConstants#STRING}.</p> |
| * |
| * <p>See <a href="#XPathExpression-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, |
| * variable, function and QName resolution and return type conversion.</p> |
| * |
| * <p>If a <code>null</code> value is provided for |
| * <code>item</code>, an empty document will be used for the |
| * context. |
| * |
| * @param item The starting context (a node, for example). |
| * |
| * @return The <code>String</code> that is the result of evaluating the expression and converting the result to a |
| * <code>String</code>. |
| * |
| * @throws XPathExpressionException If the expression cannot be evaluated. |
| */ |
| public String evaluate(Object item) |
| throws XPathExpressionException; |
| |
| /** |
| * <p>Evaluate the compiled XPath expression in the context of the specified <code>InputSource</code> and return the result as the |
| * specified type.</p> |
| * |
| * <p>This method builds a data model for the {@link InputSource} and calls |
| * {@link #evaluate(Object item, QName returnType)} on the resulting document object.</p> |
| * |
| * <p>See <a href="#XPathExpression-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, |
| * variable, function and QName resolution and return type conversion.</p> |
| * |
| * <p>If <code>returnType</code> is not one of the types defined in {@link XPathConstants}, |
| * then an <code>IllegalArgumentException</code> is thrown.</p> |
| * |
| * <p>If <code>source</code> or <code>returnType</code> is <code>null</code>, |
| * then a <code>NullPointerException</code> is thrown.</p> |
| * |
| * @param source The <code>InputSource</code> of the document to evaluate over. |
| * @param returnType The desired return type. |
| * |
| * @return The <code>Object</code> that is the result of evaluating the expression and converting the result to |
| * <code>returnType</code>. |
| * |
| * @throws XPathExpressionException If the expression cannot be evaluated. |
| * @throws IllegalArgumentException If <code>returnType</code> is not one of the types defined in {@link XPathConstants}. |
| * @throws NullPointerException If <code>source</code> or <code>returnType</code> is <code>null</code>. |
| */ |
| public Object evaluate(InputSource source, QName returnType) |
| throws XPathExpressionException; |
| |
| /** |
| * <p>Evaluate the compiled XPath expression in the context of the specified <code>InputSource</code> and return the result as a |
| * <code>String</code>.</p> |
| * |
| * <p>This method calls {@link #evaluate(InputSource source, QName returnType)} with a <code>returnType</code> of |
| * {@link XPathConstants#STRING}.</p> |
| * |
| * <p>See <a href="#XPathExpression-evaluation">Evaluation of XPath Expressions</a> for context item evaluation, |
| * variable, function and QName resolution and return type conversion.</p> |
| * |
| * <p>If <code>source</code> is <code>null</code>, then a <code>NullPointerException</code> is thrown.</p> |
| * |
| * @param source The <code>InputSource</code> of the document to evaluate over. |
| * |
| * @return The <code>String</code> that is the result of evaluating the expression and converting the result to a |
| * <code>String</code>. |
| * |
| * @throws XPathExpressionException If the expression cannot be evaluated. |
| * @throws NullPointerException If <code>source</code> is <code>null</code>. |
| */ |
| public String evaluate(InputSource source) |
| throws XPathExpressionException; |
| } |