jaxp/src/java.xml/share/classes/javax/xml/xpath/XPath.java
changeset 25868 686eef1e7a79
parent 12457 c348e06f0e82
child 28695 427254b89b9e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jaxp/src/java.xml/share/classes/javax/xml/xpath/XPath.java	Sun Aug 17 15:51:56 2014 +0100
@@ -0,0 +1,319 @@
+/*
+ * 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;
+import javax.xml.namespace.NamespaceContext;
+
+/**
+ * <p><code>XPath</code> provides access to the XPath evaluation environment and expressions.</p>
+ *
+ * <a name="XPath-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}
+ *        set with {@link #setXPathVariableResolver(XPathVariableResolver resolver)}.
+ *        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}
+ *        set with {@link #setXPathFunctionResolver(XPathFunctionResolver resolver)}.
+ *        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
+ *        set with {@link #setNamespaceContext(NamespaceContext nsContext)}.
+ *      </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 object is not thread-safe and not reentrant.
+ * In other words, it is the application's responsibility to make
+ * sure that one {@link XPath} 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="Norman.Walsh@Sun.com">Norman Walsh</a>
+ * @author  <a href="Jeff.Suttor@Sun.com">Jeff Suttor</a>
+ * @see <a href="http://www.w3.org/TR/xpath">XML Path Language (XPath) Version 1.0</a>
+ * @since 1.5
+ */
+public interface XPath {
+
+        /**
+         * <p>Reset this <code>XPath</code> to its original configuration.</p>
+         *
+         * <p><code>XPath</code> is reset to the same state as when it was created with
+         * {@link XPathFactory#newXPath()}.
+         * <code>reset()</code> is designed to allow the reuse of existing <code>XPath</code>s
+         * thus saving resources associated with the creation of new <code>XPath</code>s.</p>
+         *
+         * <p>The reset <code>XPath</code> is not guaranteed to have the same {@link XPathFunctionResolver}, {@link XPathVariableResolver}
+         * or {@link NamespaceContext} <code>Object</code>s, e.g. {@link Object#equals(Object obj)}.
+         * It is guaranteed to have a functionally equal <code>XPathFunctionResolver</code>, <code>XPathVariableResolver</code>
+         * and <code>NamespaceContext</code>.</p>
+         */
+        public void reset();
+
+    /**
+     * <p>Establish a variable resolver.</p>
+     *
+     * <p>A <code>NullPointerException</code> is thrown if <code>resolver</code> is <code>null</code>.</p>
+     *
+     * @param resolver Variable resolver.
+     *
+     *  @throws NullPointerException If <code>resolver</code> is <code>null</code>.
+     */
+    public void setXPathVariableResolver(XPathVariableResolver resolver);
+
+    /**
+       * <p>Return the current variable resolver.</p>
+       *
+       * <p><code>null</code> is returned in no variable resolver is in effect.</p>
+       *
+       * @return Current variable resolver.
+       */
+    public XPathVariableResolver getXPathVariableResolver();
+
+    /**
+       * <p>Establish a function resolver.</p>
+       *
+       * <p>A <code>NullPointerException</code> is thrown if <code>resolver</code> is <code>null</code>.</p>
+       *
+       * @param resolver XPath function resolver.
+       *
+       * @throws NullPointerException If <code>resolver</code> is <code>null</code>.
+       */
+    public void setXPathFunctionResolver(XPathFunctionResolver resolver);
+
+    /**
+       * <p>Return the current function resolver.</p>
+       *
+       * <p><code>null</code> is returned in no function resolver is in effect.</p>
+       *
+       * @return Current function resolver.
+       */
+    public XPathFunctionResolver getXPathFunctionResolver();
+
+    /**
+       * <p>Establish a namespace context.</p>
+       *
+       * <p>A <code>NullPointerException</code> is thrown if <code>nsContext</code> is <code>null</code>.</p>
+       *
+       * @param nsContext Namespace context to use.
+       *
+       * @throws NullPointerException If <code>nsContext</code> is <code>null</code>.
+       */
+    public void setNamespaceContext(NamespaceContext nsContext);
+
+    /**
+       * <p>Return the current namespace context.</p>
+       *
+       * <p><code>null</code> is returned in no namespace context is in effect.</p>
+       *
+       * @return Current Namespace context.
+       */
+    public NamespaceContext getNamespaceContext();
+
+    /**
+       * <p>Compile an XPath expression for later evaluation.</p>
+       *
+       * <p>If <code>expression</code> contains any {@link XPathFunction}s,
+       * they must be available via the {@link XPathFunctionResolver}.
+       * An {@link XPathExpressionException} will be thrown if the
+       * <code>XPathFunction</code>
+       * cannot be resovled with the <code>XPathFunctionResolver</code>.</p>
+       *
+       * <p>If <code>expression</code> contains any variables, the
+       * {@link XPathVariableResolver} in effect
+       * <strong>at compile time</strong> will be used to resolve them.</p>
+       *
+       * <p>If <code>expression</code> is <code>null</code>, a <code>NullPointerException</code> is thrown.</p>
+       *
+       * @param expression The XPath expression.
+       *
+       * @return Compiled XPath expression.
+
+       * @throws XPathExpressionException If <code>expression</code> cannot be compiled.
+       * @throws NullPointerException If <code>expression</code> is <code>null</code>.
+       */
+    public XPathExpression compile(String expression)
+        throws XPathExpressionException;
+
+    /**
+     * <p>Evaluate an <code>XPath</code> expression in the specified context and return the result as the specified type.</p>
+     *
+     * <p>See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> for context item evaluation,
+     * variable, function and <code>QName</code> resolution and return type conversion.</p>
+     *
+     * <p>If <code>returnType</code> is not one of the types defined in {@link XPathConstants} (
+     * {@link XPathConstants#NUMBER NUMBER},
+     * {@link XPathConstants#STRING STRING},
+     * {@link XPathConstants#BOOLEAN BOOLEAN},
+     * {@link XPathConstants#NODE NODE} or
+     * {@link XPathConstants#NODESET NODESET})
+     * 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>expression</code> or <code>returnType</code> is <code>null</code>, then a
+     * <code>NullPointerException</code> is thrown.</p>
+     *
+     * @param expression The XPath expression.
+     * @param item The starting context (a node, for example).
+     * @param returnType The desired return type.
+     *
+     * @return Result of evaluating an XPath expression as an <code>Object</code> of <code>returnType</code>.
+     *
+     * @throws XPathExpressionException If <code>expression</code> cannot be evaluated.
+     * @throws IllegalArgumentException If <code>returnType</code> is not one of the types defined in {@link XPathConstants}.
+     * @throws NullPointerException If <code>expression</code> or <code>returnType</code> is <code>null</code>.
+     */
+    public Object evaluate(String expression, Object item, QName returnType)
+        throws XPathExpressionException;
+
+    /**
+     * <p>Evaluate an XPath expression in the specified context and return the result as a <code>String</code>.</p>
+     *
+     * <p>This method calls {@link #evaluate(String expression, Object item, QName returnType)} with a <code>returnType</code> of
+     * {@link XPathConstants#STRING}.</p>
+     *
+     * <p>See <a href="#XPath-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.
+     * If <code>expression</code> is <code>null</code>, then a <code>NullPointerException</code> is thrown.</p>
+     *
+     * @param expression The XPath expression.
+     * @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 <code>expression</code> cannot be evaluated.
+     * @throws NullPointerException If <code>expression</code> is <code>null</code>.
+     */
+    public String evaluate(String expression, Object item)
+        throws XPathExpressionException;
+
+    /**
+     * <p>Evaluate an 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(String expression, Object item, QName returnType)} on the resulting document object.</p>
+     *
+     * <p>See <a href="#XPath-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>expression</code>, <code>source</code> or <code>returnType</code> is <code>null</code>,
+     * then a <code>NullPointerException</code> is thrown.</p>
+     *
+     * @param expression The XPath expression.
+     * @param source The input source of the document to evaluate over.
+     * @param returnType The desired return type.
+     *
+     * @return The <code>Object</code> that encapsulates the result of evaluating the expression.
+     *
+     * @throws XPathExpressionException If expression cannot be evaluated.
+     * @throws IllegalArgumentException If <code>returnType</code> is not one of the types defined in {@link XPathConstants}.
+     * @throws NullPointerException If <code>expression</code>, <code>source</code> or <code>returnType</code>
+     *   is <code>null</code>.
+     */
+    public Object evaluate(
+        String expression,
+        InputSource source,
+        QName returnType)
+        throws XPathExpressionException;
+
+    /**
+     * <p>Evaluate an 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(String expression, InputSource source, QName returnType)} with a
+     * <code>returnType</code> of {@link XPathConstants#STRING}.</p>
+     *
+     * <p>See <a href="#XPath-evaluation">Evaluation of XPath Expressions</a> for context item evaluation,
+     * variable, function and QName resolution and return type conversion.</p>
+     *
+     * <p>If <code>expression</code> or <code>source</code> is <code>null</code>,
+     * then a <code>NullPointerException</code> is thrown.</p>
+     *
+     * @param expression The XPath expression.
+     * @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 expression cannot be evaluated.
+     * @throws NullPointerException If <code>expression</code> or <code>source</code> is <code>null</code>.
+     */
+    public String evaluate(String expression, InputSource source)
+        throws XPathExpressionException;
+}