code: /*
   * 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.
   */
  // $Id$
  
  package org.apache.xpath.jaxp;
  
  import org.apache.xpath.res.XPATHErrorResources;
  import org.apache.xalan.res.XSLMessages;
  
  import javax.xml.XMLConstants;
  import javax.xml.xpath.XPathFactory;
  import javax.xml.xpath.XPathFactoryConfigurationException;
  import javax.xml.xpath.XPathFunctionResolver;
  import javax.xml.xpath.XPathVariableResolver;
  
  /**
   * The XPathFactory builds XPaths.
   *
   * @version $Revision$
   * @author  Ramesh Mandava
   */
  public class XPathFactoryImpl extends XPathFactory {
  	
  	/**
  	 * <p>Name of class as a constant to use for debugging.</p>
  	 */
  	private static final String CLASS_NAME = "XPathFactoryImpl";
  	
  	/**
  	 *<p>XPathFunctionResolver for this XPathFactory and created XPaths.</p>
  	 */
  	private XPathFunctionResolver xPathFunctionResolver = null;
  	
  	/**
  	 * <p>XPathVariableResolver for this XPathFactory and created XPaths</p>
  	 */
  	private XPathVariableResolver xPathVariableResolver = null;
  
  	/**
  	 * <p>State of secure processing feature.</p>
  	 */
  	private boolean featureSecureProcessing = false;
  		
  	/**
  	 * <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 boolean isObjectModelSupported(String objectModel) {
  		
              if (objectModel == null) {
                  String fmsg = XSLMessages.createXPATHMessage(
                          XPATHErrorResources.ER_OBJECT_MODEL_NULL,
                          new Object[] { this.getClass().getName() } );
  
                  throw new NullPointerException( fmsg );
              }
  		
              if (objectModel.length() == 0) {
                  String fmsg = XSLMessages.createXPATHMessage(
                          XPATHErrorResources.ER_OBJECT_MODEL_EMPTY,
                          new Object[] { this.getClass().getName() } );
                  throw new IllegalArgumentException( fmsg );
              }
  		
  	    // know how to support default object model, W3C DOM
              if (objectModel.equals(XPathFactory.DEFAULT_OBJECT_MODEL_URI)) {
                  return true;
              }
  		
              // don't know how to support anything else
              return false;
  	}
  
          /**
           * <p>Returns a new <code>XPath</code> object using the underlying
           * object model determined when the factory was instantiated.</p>
  	 * 
  	 * @return New <code>XPath</code>
  	 */
  	public javax.xml.xpath.XPath newXPath() {
  	    return new org.apache.xpath.jaxp.XPathImpl(
                      xPathVariableResolver, xPathFunctionResolver,
                      featureSecureProcessing );
  	}
  	    
  	/**
  	 * <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>See {@link javax.xml.xpath.XPathFactory} for full documentation
           * of specific features.</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 void setFeature(String name, boolean value)
  		throws XPathFactoryConfigurationException {
  			
              // feature name cannot be null
              if (name == null) {
                  String fmsg = XSLMessages.createXPATHMessage(
                          XPATHErrorResources.ER_FEATURE_NAME_NULL,
                          new Object[] { CLASS_NAME, value ? Boolean.TRUE : Boolean.FALSE } );
                  throw new NullPointerException( fmsg );
               }
  		
              // secure processing?
              if (name.equals(XMLConstants.FEATURE_SECURE_PROCESSING)) {
  
                  featureSecureProcessing = value;
  						
                  // all done processing feature
                  return;
              }
  		
              // unknown feature
              String fmsg = XSLMessages.createXPATHMessage(
                      XPATHErrorResources.ER_FEATURE_UNKNOWN,
                      new Object[] { name, CLASS_NAME, value ? Boolean.TRUE : Boolean.FALSE } );
              throw new XPathFactoryConfigurationException( fmsg );
  	}
  
  	/**
  	 * <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 boolean getFeature(String name)
  		throws XPathFactoryConfigurationException {
  
              // feature name cannot be null
              if (name == null) {
                  String fmsg = XSLMessages.createXPATHMessage(
                          XPATHErrorResources.ER_GETTING_NULL_FEATURE,
                          new Object[] { CLASS_NAME } );
                  throw new NullPointerException( fmsg );
              }
  		
              // secure processing?
              if (name.equals(XMLConstants.FEATURE_SECURE_PROCESSING)) {
                  return featureSecureProcessing;
              }
  		
              // unknown feature
              String fmsg = XSLMessages.createXPATHMessage(
                      XPATHErrorResources.ER_GETTING_UNKNOWN_FEATURE,
                      new Object[] { name, CLASS_NAME } );
  
              throw new XPathFactoryConfigurationException( fmsg );
          }
  		
  	/**
           * <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 void setXPathFunctionResolver(XPathFunctionResolver resolver) {
  			
              // resolver cannot be null
              if (resolver == null) {
                  String fmsg = XSLMessages.createXPATHMessage(
                          XPATHErrorResources.ER_NULL_XPATH_FUNCTION_RESOLVER,
                          new Object[] {  CLASS_NAME } );
                  throw new NullPointerException( fmsg );
              }
  			
              xPathFunctionResolver = resolver;
          }
  		
  	/**
  	 * <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 void setXPathVariableResolver(XPathVariableResolver resolver) {
  
  		// resolver cannot be null
  		if (resolver == null) {
                      String fmsg = XSLMessages.createXPATHMessage(
                              XPATHErrorResources.ER_NULL_XPATH_VARIABLE_RESOLVER,
                              new Object[] {  CLASS_NAME } );
  		    throw new NullPointerException( fmsg );
  		}
  			
  		xPathVariableResolver = resolver;
  	}
  }
  
  
  
  