- // $Id: XPathExpression.java,v 1.10.16.1 2004/07/01 17:49:23 ndw Exp $
-
- /*
- * @(#)XPathExpression.java 1.6 04/07/26
- *
- * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
- * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
- */
-
- 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>
- *
- * <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:Norman.Walsh@Sun.com">Norman Walsh</a>
- * @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
- * @version $Revision: 1.10.16.1 $, $Date: 2004/07/01 17:49:23 $
- * @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;
- }