content: package org.jaxen.dom4j;
  
  /*
   * $Header$
   * $Revision$
   * $Date$
   *
   * ====================================================================
   *
   * Copyright 2000-2005 bob mcwhirter & James Strachan.
   * All rights reserved.
   *
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   * 
   *   * Redistributions of source code must retain the above copyright
   *     notice, this list of conditions and the following disclaimer.
   * 
   *   * Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution.
   * 
   *   * Neither the name of the Jaxen Project nor the names of its
   *     contributors may be used to endorse or promote products derived 
   *     from this software without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
   * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * ====================================================================
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Jaxen Project and was originally
   * created by bob mcwhirter <bob@werken.com> and
   * James Strachan <jstrachan@apache.org>.  For more information on the
   * Jaxen Project, please see <http://www.jaxen.org/>.
   *
   * $Id$
  */
  
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  
  import org.dom4j.Attribute;
  import org.dom4j.Branch;
  import org.dom4j.CDATA;
  import org.dom4j.Comment;
  import org.dom4j.Document;
  import org.dom4j.DocumentException;
  import org.dom4j.Element;
  import org.dom4j.Namespace;
  import org.dom4j.Node;
  import org.dom4j.ProcessingInstruction;
  import org.dom4j.QName;
  import org.dom4j.Text;
  import org.dom4j.io.SAXReader;
  import org.jaxen.DefaultNavigator;
  import org.jaxen.FunctionCallException;
  import org.jaxen.NamedAccessNavigator;
  import org.jaxen.Navigator;
  import org.jaxen.XPath;
  import org.jaxen.JaxenConstants;
  import org.jaxen.saxpath.SAXPathException;
  import org.jaxen.util.SingleObjectIterator;
  
  /** 
   * Interface for navigating around the DOM4J object model.
   *
   * <p>
   * This class is not intended for direct usage, but is
   * used by the Jaxen engine during evaluation.
   * </p>
   *
   * @see XPath
   *
   * @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
   * @author Stephen Colebourne
   */
  public class DocumentNavigator extends DefaultNavigator implements NamedAccessNavigator
  {
      
      /**
       * 
       */
      private static final long serialVersionUID = 5582300797286535936L;
      private transient SAXReader reader;
  
      /** Singleton implementation.
       */
      private static class Singleton
      {
          /** Singleton instance.
           */
          private static DocumentNavigator instance = new DocumentNavigator();
      }
  
      /** Retrieve the singleton instance of this <code>DocumentNavigator</code>.
       */
      public static Navigator getInstance()
      {
          return Singleton.instance;
      }
  
      public boolean isElement(Object obj)
      {
          return obj instanceof Element;
      }
  
      public boolean isComment(Object obj)
      {
          return obj instanceof Comment;
      }
  
      public boolean isText(Object obj)
      {
          return ( obj instanceof Text 
                   ||
                   obj instanceof CDATA );
      }
  
      public boolean isAttribute(Object obj)
      {
          return obj instanceof Attribute;
      }
  
      public boolean isProcessingInstruction(Object obj)
      {
          return obj instanceof ProcessingInstruction;
      }
  
      public boolean isDocument(Object obj)
      {
          return obj instanceof Document;
      }
  
      public boolean isNamespace(Object obj)
      {
          return obj instanceof Namespace;
      }
  
      public String getElementName(Object obj)
      {
          Element elem = (Element) obj;
  
          return elem.getName();
      }
  
      public String getElementNamespaceUri(Object obj)
      {
          Element elem = (Element) obj;
          
          String uri = elem.getNamespaceURI();
          if ( uri == null)
              return "";
          else
              return uri;
      }
  
      public String getElementQName(Object obj)
      {
          Element elem = (Element) obj;
  
          return elem.getQualifiedName();
      }
  
      public String getAttributeName(Object obj)
      {
          Attribute attr = (Attribute) obj;
  
          return attr.getName();
      }
  
      public String getAttributeNamespaceUri(Object obj)
      {
          Attribute attr = (Attribute) obj;
  
          String uri = attr.getNamespaceURI();
          if ( uri == null)
              return "";
          else
              return uri;
      }
  
      public String getAttributeQName(Object obj)
      {
          Attribute attr = (Attribute) obj;
  
          return attr.getQualifiedName();
      }
  
      public Iterator getChildAxisIterator(Object contextNode)
      {
          Iterator result = null;
          if ( contextNode instanceof Branch )
          {
              Branch node = (Branch) contextNode;
              result = node.nodeIterator();
          }
          if (result != null) {
              return result;
          }
          return JaxenConstants.EMPTY_ITERATOR;
      }
  
      /**
       * Retrieves an <code>Iterator</code> over the child elements that
       * match the supplied name.
       *
       * @param contextNode      the origin context node
       * @param localName        the local name of the children to return, always present
       * @param namespacePrefix  the prefix of the namespace of the children to return
       * @param namespaceURI     the uri of the namespace of the children to return
       * 
       * @return an Iterator that traverses the named children, or null if none
       */
      public Iterator getChildAxisIterator(
              Object contextNode, String localName, String namespacePrefix, String namespaceURI) {
  
          if ( contextNode instanceof Element ) {
              Element node = (Element) contextNode;
              return node.elementIterator(QName.get(localName, namespacePrefix, namespaceURI));
          }
          if ( contextNode instanceof Document ) {
              Document node = (Document) contextNode;
              Element el = node.getRootElement();
              if (el == null || el.getName().equals(localName) == false) {
                  return JaxenConstants.EMPTY_ITERATOR;
              }
              if (namespaceURI != null) {
                  if (namespaceURI.equals(el.getNamespaceURI()) == false) {
                      return JaxenConstants.EMPTY_ITERATOR;
                  }
              }
              return new SingleObjectIterator(el);
          }
  
          return JaxenConstants.EMPTY_ITERATOR;
      }
  
      public Iterator getParentAxisIterator(Object contextNode)
      {
          if ( contextNode instanceof Document )
          {
              return JaxenConstants.EMPTY_ITERATOR;
          }
  
          Node node = (Node) contextNode;
  
          Object parent = node.getParent();
  
          if ( parent == null )
          {
              parent = node.getDocument();
          }
          
          return new SingleObjectIterator( parent );
      }
  
      public Iterator getAttributeAxisIterator(Object contextNode)
      {
          if ( ! ( contextNode instanceof Element ) )
          {
              return JaxenConstants.EMPTY_ITERATOR;
          }
  
          Element elem = (Element) contextNode;
  
          return elem.attributeIterator();
      }
  
      /**
       * Retrieves an <code>Iterator</code> over the attribute elements that
       * match the supplied name.
       *
       * @param contextNode  the origin context node
       * @param localName  the local name of the attributes to return, always present
       * @param namespacePrefix  the prefix of the namespace of the attributes to return
       * @param namespaceURI  the URI of the namespace of the attributes to return
       * @return an Iterator that traverses the named attributes, not null
       */
      public Iterator getAttributeAxisIterator(
              Object contextNode, String localName, String namespacePrefix, String namespaceURI) {
  
          if ( contextNode instanceof Element ) {
              Element node = (Element) contextNode;
              Attribute attr = node.attribute(QName.get(localName, namespacePrefix, namespaceURI));
              if (attr == null) {
                  return JaxenConstants.EMPTY_ITERATOR;
              }
              return new SingleObjectIterator(attr);
          }
          return JaxenConstants.EMPTY_ITERATOR;
      }
          
      public Iterator getNamespaceAxisIterator(Object contextNode)
      {
          if ( ! ( contextNode instanceof Element ) )
          {
              return JaxenConstants.EMPTY_ITERATOR;
          }
  
          Element element = (Element) contextNode;
          List nsList = new ArrayList();
          HashSet prefixes = new HashSet();
          for ( Element context = element; context != null; context = context.getParent() ) {
              List declaredNS = new ArrayList(context.declaredNamespaces());
              declaredNS.add(context.getNamespace());
  
              for ( Iterator iter = context.attributes().iterator(); iter.hasNext(); )
              {
                  Attribute attr = (Attribute) iter.next();
                  declaredNS.add(attr.getNamespace());
              }
  
              for ( Iterator iter = declaredNS.iterator(); iter.hasNext(); )
              {
                  Namespace namespace = (Namespace) iter.next();
                  if (namespace != Namespace.NO_NAMESPACE)
                  {
                      String prefix = namespace.getPrefix();
                      if ( ! prefixes.contains( prefix ) ) {
                          prefixes.add( prefix );
                          nsList.add( namespace.asXPathResult( element ) );
                      }
                  }
              }
          }
          nsList.add( Namespace.XML_NAMESPACE.asXPathResult( element ) );
          return nsList.iterator();
      }
  
      public Object getDocumentNode(Object contextNode)
      {
          if ( contextNode instanceof Document ) 
          {
              return contextNode;
          }
          else if ( contextNode instanceof Node ) 
          {
              Node node = (Node) contextNode;
              return node.getDocument();
          }
          return null;
      }
  
      /** Returns a parsed form of the given XPath string, which will be suitable
       *  for queries on DOM4J documents.
       */
      public XPath parseXPath (String xpath) throws SAXPathException
      {
          return new Dom4jXPath(xpath);
      }
  
      public Object getParentNode(Object contextNode)
      {
          if ( contextNode instanceof Node ) 
          {
              Node node = (Node) contextNode;
              Object answer = node.getParent();
              if ( answer == null ) 
              {
                  answer = node.getDocument();
                  if (answer == contextNode) {
                      return null;
                  }
              }
              return answer;            
          }
          return null;
      }
  
      public String getTextStringValue(Object obj)
      {
          return getNodeStringValue( (Node) obj );
      }
  
      public String getElementStringValue(Object obj)
      {
          return getNodeStringValue( (Node) obj );
      }
  
      public String getAttributeStringValue(Object obj)
      {
          return getNodeStringValue( (Node) obj );
      }
  
      private String getNodeStringValue(Node node)
      {
          return node.getStringValue();
      }
  
      public String getNamespaceStringValue(Object obj)
      {
          Namespace ns = (Namespace) obj;
  
          return ns.getURI();
      }
  
      public String getNamespacePrefix(Object obj)
      {
          Namespace ns = (Namespace) obj;
  
          return ns.getPrefix();
      }
  
      public String getCommentStringValue(Object obj)
      {
          Comment cmt = (Comment) obj;
  
          return cmt.getText();
      }
      
      public String translateNamespacePrefixToUri(String prefix, Object context)
      {
          Element element = null;
          if ( context instanceof Element ) 
          {
              element = (Element) context;
          }
          else if ( context instanceof Node )
          {
              Node node = (Node) context;
              element = node.getParent();
          }
          if ( element != null )
          {
              Namespace namespace = element.getNamespaceForPrefix( prefix );
  
              if ( namespace != null ) 
              {
                  return namespace.getURI();
              }
          }
          return null;
      }
      
      public short getNodeType(Object node) 
      {
          if ( node instanceof Node )
          {
              return ((Node) node).getNodeType();
          }
          return 0;
      }
      
      public Object getDocument(String uri) throws FunctionCallException
      {
          try
          {
              return getSAXReader().read( uri );
          }
          catch (DocumentException e)
          {
              throw new FunctionCallException("Failed to parse document for URI: " + uri, e);
          }
      }
  
      public String getProcessingInstructionTarget(Object obj)
      {
          ProcessingInstruction pi = (ProcessingInstruction) obj;
  
          return pi.getTarget();
      }
  
      public String getProcessingInstructionData(Object obj)
      {
          ProcessingInstruction pi = (ProcessingInstruction) obj;
  
          return pi.getText();
      }
      
      // Properties
      //-------------------------------------------------------------------------    
      public SAXReader getSAXReader()
      {
          if ( reader == null ) 
          {
              reader = new SAXReader();
              reader.setMergeAdjacentText( true );
          }
          return reader;
      }
      
      public void setSAXReader(SAXReader reader)
      {
          this.reader = reader;
      }
      
  }
  