| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| // $Id: XPathExpression.java 446598 2006-09-15 12:55:40Z jeremias $ |
| |
| package javax.xml.xpath; |
| |
| import javax.xml.namespace.QName; |
| import org.xml.sax.InputSource; |
| |
| /** |
| * <p><code>XPathExpression</code> provides access to compiled XPath expressions.</p> |
| * |
| * <table id="XPathExpression-evaluation" 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> |
| * |
| * @author <a href="mailto:[email protected]">Norman Walsh</a> |
| * @author <a href="mailto:[email protected]">Jeff Suttor</a> |
| * @version $Revision: 446598 $, $Date: 2006-09-15 05:55:40 -0700 (Fri, 15 Sep 2006) $ |
| * @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 (node or node list, 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 (node or node list, 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; |
| } |
