| /* |
| * 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: XPathFactory.java 888889 2009-12-09 17:43:18Z mrglavas $ |
| |
| package javax.xml.xpath; |
| |
| /** |
| * <p>An <code>XPathFactory</code> instance can be used to create |
| * {@link javax.xml.xpath.XPath} objects.</p> |
| * |
| *<p>See {@link #newInstance(String uri)} for lookup mechanism.</p> |
| * |
| * @author <a href="mailto:Norman.Walsh@Sun.com">Norman Walsh</a> |
| * @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a> |
| * @version $Revision: 888889 $, $Date: 2009-12-09 09:43:18 -0800 (Wed, 09 Dec 2009) $ |
| * @since 1.5 |
| */ |
| public abstract class XPathFactory { |
| |
| |
| /** |
| * <p>The default property name according to the JAXP spec.</p> |
| */ |
| public static final String DEFAULT_PROPERTY_NAME = "javax.xml.xpath.XPathFactory"; |
| |
| /** |
| * <p>Default Object Model URI.</p> |
| */ |
| public static final String DEFAULT_OBJECT_MODEL_URI = "http://java.sun.com/jaxp/xpath/dom"; |
| |
| /** |
| * <p>Protected constructor as {@link #newInstance()}, {@link #newInstance(String uri)} |
| * or {@link #newInstance(String uri, String factoryClassName, ClassLoader classLoader)} |
| * should be used to create a new instance of an <code>XPathFactory</code>.</p> |
| */ |
| protected XPathFactory() { |
| } |
| |
| /** |
| * <p>Get a new <code>XPathFactory</code> instance using the default object model, |
| * {@link #DEFAULT_OBJECT_MODEL_URI}, |
| * the W3C DOM.</p> |
| * |
| * <p>This method is functionally equivalent to:</p> |
| * <pre> |
| * newInstance(DEFAULT_OBJECT_MODEL_URI) |
| * </pre> |
| * |
| * <p>Since the implementation for the W3C DOM is always available, this method will never fail.</p> |
| * |
| * @return Instance of an <code>XPathFactory</code>. |
| */ |
| public static final XPathFactory newInstance() { |
| try { |
| return newInstance(DEFAULT_OBJECT_MODEL_URI); |
| } |
| catch (XPathFactoryConfigurationException xpathFactoryConfigurationException) { |
| throw new RuntimeException( |
| "XPathFactory#newInstance() failed to create an XPathFactory for the default object model: " |
| + DEFAULT_OBJECT_MODEL_URI |
| + " with the XPathFactoryConfigurationException: " |
| + xpathFactoryConfigurationException.toString() |
| ); |
| } |
| } |
| |
| /** |
| * <p>Get a new <code>XPathFactory</code> instance using the specified object model.</p> |
| * |
| * <p>To find a <code>XPathFactory</code> object, |
| * this method looks the following places in the following order where "the class loader" refers to the context class loader:</p> |
| * <ol> |
| * <li> |
| * If the system property {@link #DEFAULT_PROPERTY_NAME} + ":uri" is present, |
| * where uri is the parameter to this method, then its value is read as a class name. |
| * The method will try to create a new instance of this class by using the class loader, |
| * and returns it if it is successfully created. |
| * </li> |
| * <li> |
| * ${java.home}/lib/jaxp.properties is read and the value associated with the key being the system property above is looked for. |
| * If present, the value is processed just like above. |
| * </li> |
| * <li> |
| * The class loader is asked for service provider provider-configuration files matching <code>javax.xml.xpath.XPathFactory</code> |
| * in the resource directory META-INF/services. |
| * See the JAR File Specification for file format and parsing rules. |
| * Each potential service provider is required to implement the method: |
| * <pre> |
| * {@link #isObjectModelSupported(String objectModel)} |
| * </pre> |
| * The first service provider found in class loader order that supports the specified object model is returned. |
| * </li> |
| * <li> |
| * Platform default <code>XPathFactory</code> is located in a platform specific way. |
| * There must be a platform default XPathFactory for the W3C DOM, i.e. {@link #DEFAULT_OBJECT_MODEL_URI}. |
| * </li> |
| * </ol> |
| * <p>If everything fails, an <code>XPathFactoryConfigurationException</code> will be thrown.</p> |
| * |
| * <p>Tip for Trouble-shooting:</p> |
| * <p>See {@link java.util.Properties#load(java.io.InputStream)} for exactly how a property file is parsed. |
| * In particular, colons ':' need to be escaped in a property file, so make sure the URIs are properly escaped in it. |
| * For example:</p> |
| * <pre> |
| * http\://java.sun.com/jaxp/xpath/dom=org.acme.DomXPathFactory |
| * </pre> |
| * |
| * @param uri Identifies the underlying object model. |
| * The specification only defines the URI {@link #DEFAULT_OBJECT_MODEL_URI}, |
| * <code>http://java.sun.com/jaxp/xpath/dom</code> for the W3C DOM, |
| * the org.w3c.dom package, and implementations are free to introduce other URIs for other object models. |
| * |
| * @return Instance of an <code>XPathFactory</code>. |
| * |
| * @throws XPathFactoryConfigurationException If the specified object model is unavailable. |
| * @throws NullPointerException If <code>uri</code> is <code>null</code>. |
| * @throws IllegalArgumentException If <code>uri.length() == 0</code>. |
| */ |
| public static final XPathFactory newInstance(final String uri) |
| throws XPathFactoryConfigurationException { |
| if (uri == null) { |
| throw new NullPointerException("uri == null"); |
| } |
| if (uri.length() == 0) { |
| throw new IllegalArgumentException( |
| "XPathFactory#newInstance(String uri) cannot be called with uri == \"\"" |
| ); |
| } |
| ClassLoader classLoader = Thread.currentThread().getContextClassLoader(); |
| if (classLoader == null) { |
| //use the current class loader |
| classLoader = XPathFactory.class.getClassLoader(); |
| } |
| XPathFactory xpathFactory = new XPathFactoryFinder(classLoader).newFactory(uri); |
| if (xpathFactory == null) { |
| throw new XPathFactoryConfigurationException( |
| "No XPathFactory implementation found for the object model: " |
| + uri |
| ); |
| } |
| return xpathFactory; |
| } |
| |
| /** |
| * @return Instance of an <code>XPathFactory</code>. |
| * |
| * @throws XPathFactoryConfigurationException If the specified object model is unavailable. |
| * @throws NullPointerException If <code>uri</code> is <code>null</code>. |
| * @throws IllegalArgumentException If <code>uri.length() == 0</code>. |
| */ |
| public static XPathFactory newInstance(String uri, String factoryClassName, |
| ClassLoader classLoader) throws XPathFactoryConfigurationException { |
| if (uri == null) { |
| throw new NullPointerException("uri == null"); |
| } |
| if (uri.length() == 0) { |
| throw new IllegalArgumentException( |
| "XPathFactory#newInstance(String uri) cannot be called with uri == \"\"" |
| ); |
| } |
| if (factoryClassName == null) { |
| throw new XPathFactoryConfigurationException("factoryClassName cannot be null."); |
| } |
| if (classLoader == null) { |
| classLoader = Thread.currentThread().getContextClassLoader(); |
| } |
| XPathFactory xpathFactory = new XPathFactoryFinder(classLoader).createInstance(factoryClassName); |
| if (xpathFactory == null || !xpathFactory.isObjectModelSupported(uri)) { |
| throw new XPathFactoryConfigurationException( |
| "No XPathFactory implementation found for the object model: " |
| + uri |
| ); |
| } |
| return xpathFactory; |
| } |
| |
| /** |
| * <p>Is specified object model supported by this <code>XPathFactory</code>?</p> |
| * |
| * @param objectModel Specifies the object model which the returned <code>XPathFactory</code> will understand. |
| * |
| * @return <code>true</code> if <code>XPathFactory</code> supports <code>objectModel</code>, else <code>false</code>. |
| * |
| * @throws NullPointerException If <code>objectModel</code> is <code>null</code>. |
| * @throws IllegalArgumentException If <code>objectModel.length() == 0</code>. |
| */ |
| public abstract boolean isObjectModelSupported(String objectModel); |
| |
| /** |
| * <p>Set a feature for this <code>XPathFactory</code> and <code>XPath</code>s created by this factory.</p> |
| * |
| * <p> |
| * Feature names are fully qualified {@link java.net.URI}s. |
| * Implementations may define their own features. |
| * An {@link XPathFactoryConfigurationException} is thrown if this <code>XPathFactory</code> or the <code>XPath</code>s |
| * it creates cannot support the feature. |
| * It is possible for an <code>XPathFactory</code> to expose a feature value but be unable to change its state. |
| * </p> |
| * |
| * <p> |
| * All implementations are required to support the {@link javax.xml.XMLConstants#FEATURE_SECURE_PROCESSING} feature. |
| * When the feature is <code>true</code>, any reference to an external function is an error. |
| * Under these conditions, the implementation must not call the {@link XPathFunctionResolver} |
| * and must throw an {@link XPathFunctionException}. |
| * </p> |
| * |
| * @param name Feature name. |
| * @param value Is feature state <code>true</code> or <code>false</code>. |
| * |
| * @throws XPathFactoryConfigurationException if this <code>XPathFactory</code> or the <code>XPath</code>s |
| * it creates cannot support this feature. |
| * @throws NullPointerException if <code>name</code> is <code>null</code>. |
| */ |
| public abstract void setFeature(String name, boolean value) |
| throws XPathFactoryConfigurationException; |
| |
| /** |
| * <p>Get the state of the named feature.</p> |
| * |
| * <p> |
| * Feature names are fully qualified {@link java.net.URI}s. |
| * Implementations may define their own features. |
| * An {@link XPathFactoryConfigurationException} is thrown if this <code>XPathFactory</code> or the <code>XPath</code>s |
| * it creates cannot support the feature. |
| * It is possible for an <code>XPathFactory</code> to expose a feature value but be unable to change its state. |
| * </p> |
| * |
| * @param name Feature name. |
| * |
| * @return State of the named feature. |
| * |
| * @throws XPathFactoryConfigurationException if this <code>XPathFactory</code> or the <code>XPath</code>s |
| * it creates cannot support this feature. |
| * @throws NullPointerException if <code>name</code> is <code>null</code>. |
| */ |
| public abstract boolean getFeature(String name) |
| throws XPathFactoryConfigurationException; |
| |
| /** |
| * <p>Establish a default variable resolver.</p> |
| * |
| * <p>Any <code>XPath</code> objects constructed from this factory will use |
| * the specified resolver by default.</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 abstract void setXPathVariableResolver(XPathVariableResolver resolver); |
| |
| /** |
| * <p>Establish a default function resolver.</p> |
| * |
| * <p>Any <code>XPath</code> objects constructed from this factory will use |
| * the specified resolver by default.</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 abstract void setXPathFunctionResolver(XPathFunctionResolver resolver); |
| |
| /** |
| * <p>Return a new <code>XPath</code> using the underlying object |
| * model determined when the <code>XPathFactory</code> was instantiated.</p> |
| * |
| * @return New instance of an <code>XPath</code>. |
| */ |
| public abstract XPath newXPath(); |
| } |
