package org.jaxen.jdom;
   
   /*
    * $Header$
    * $Revision$
    * $Date$
    *
    * ====================================================================
    *
   * 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.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  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;
  import org.jdom.Attribute;
  import org.jdom.CDATA;
  import org.jdom.Comment;
  import org.jdom.Document;
  import org.jdom.Element;
  import org.jdom.Namespace;
  import org.jdom.ProcessingInstruction;
  import org.jdom.Text;
  import org.jdom.input.SAXBuilder;
  
  /** 
   * Interface for navigating around the JDOM 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 = -1636727587303584165L;
  
      /** Singleton implementation.
       */
      private static class Singleton
      {
          /** Singleton instance.
           */
         private static DocumentNavigator instance = new DocumentNavigator();
     }
 
     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 || obj instanceof XPathNamespace;
     }
 
     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 && uri.length() == 0 ) 
             return null;
         else
             return uri;
     }
 
     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 && uri.length() == 0 ) 
             return null;
         else
             return uri;
     }
 
     public Iterator getChildAxisIterator(Object contextNode)
     {
         if ( contextNode instanceof Element )
         {
             return ((Element)contextNode).getContent().iterator();
         }
         else if ( contextNode instanceof Document )
         {
             return ((Document)contextNode).getContent().iterator();
         }
 
         return JaxenConstants.EMPTY_ITERATOR;
     }
 
     /**
      * Retrieves an <code>Iterator</code> over the child elements that
      * match the supplied local name and namespace URI.
      *
      * @param contextNode      the origin context node
      * @param localName        the local name of the children to return, always present
      * @param namespacePrefix  ignored; prefixes are not used when matching in XPath
      * @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;
             if (namespaceURI == null) {
                 return node.getChildren(localName).iterator();
             }
             return node.getChildren(localName, Namespace.getNamespace(namespacePrefix, namespaceURI)).iterator();
         }
         if ( contextNode instanceof Document ) {
             Document node = (Document) contextNode;
             
             Element el = node.getRootElement();
             if (el.getName().equals(localName) == false) {
                 return JaxenConstants.EMPTY_ITERATOR;
             }
             if (namespaceURI != null) {
                 // JDOM's equals method does not consider the prefix when comparing namespace objects
                 if (!Namespace.getNamespace(namespacePrefix, namespaceURI).equals(el.getNamespace())) {
                     return JaxenConstants.EMPTY_ITERATOR;
                 }
             }
             else if(el.getNamespace() != Namespace.NO_NAMESPACE) { 
                 return JaxenConstants.EMPTY_ITERATOR; 
             }
             
             return new SingleObjectIterator(el);
         }
 
         return JaxenConstants.EMPTY_ITERATOR;
     }
     
     public Iterator getNamespaceAxisIterator(Object contextNode)
     {
         if ( ! ( contextNode instanceof Element ) )
         {
             return JaxenConstants.EMPTY_ITERATOR;
         }
 
         Element elem = (Element) contextNode;
 
         Map nsMap = new HashMap();
 
         Element current = elem;
 
         while ( current != null ) {
         
             Namespace ns = current.getNamespace();
             
             if ( ns != Namespace.NO_NAMESPACE ) {
                 if ( !nsMap.containsKey(ns.getPrefix()) )
                     nsMap.put( ns.getPrefix(), new XPathNamespace(elem, ns) );
             }
         
             Iterator additional = current.getAdditionalNamespaces().iterator();
 
             while ( additional.hasNext() ) {
 
                 ns = (Namespace)additional.next();
                 if ( !nsMap.containsKey(ns.getPrefix()) )
                     nsMap.put( ns.getPrefix(), new XPathNamespace(elem, ns) );
             }
 
             Iterator attributes = current.getAttributes().iterator();
 
             while ( attributes.hasNext() ) {
 
                 Attribute attribute = (Attribute)attributes.next();
 
                 Namespace attrNS = attribute.getNamespace();
             
                 if ( attrNS != Namespace.NO_NAMESPACE ) {
                     if ( !nsMap.containsKey(attrNS.getPrefix()) )
                         nsMap.put( attrNS.getPrefix(), new XPathNamespace(elem, attrNS) );
                 }
             }
 
             if (current.getParent() instanceof Element) {
                 current = (Element)current.getParent();
             } else {
                 current = null;
             }
         }
 
         nsMap.put( "xml", new XPathNamespace(elem, Namespace.XML_NAMESPACE) );
 
         return nsMap.values().iterator();
     }
 
     public Iterator getParentAxisIterator(Object contextNode)
     {
         Object parent = null;
 
         if ( contextNode instanceof Document )
         {
             return JaxenConstants.EMPTY_ITERATOR;
         }
         else if ( contextNode instanceof Element )
         {
             parent = ((Element)contextNode).getParent();
 
             if ( parent == null )
             {
                 if ( ((Element)contextNode).isRootElement() )
                 {
                     parent = ((Element)contextNode).getDocument();
                 }
             }
         }
         else if ( contextNode instanceof Attribute )
         {
             parent = ((Attribute)contextNode).getParent();
         }
         else if ( contextNode instanceof XPathNamespace )
         {
             parent = ((XPathNamespace)contextNode).getJDOMElement();
         }
         else if ( contextNode instanceof ProcessingInstruction )
         {
             parent = ((ProcessingInstruction)contextNode).getParent();
         }
         else if ( contextNode instanceof Comment )
         {
             parent = ((Comment)contextNode).getParent();
         }
         else if ( contextNode instanceof Text )
         {
             parent = ((Text)contextNode).getParent();
         }
         
         if ( parent != null )
         {
             return new SingleObjectIterator( parent );
         }
 
         return JaxenConstants.EMPTY_ITERATOR;
     }
 
     public Iterator getAttributeAxisIterator(Object contextNode)
     {
         if ( ! ( contextNode instanceof Element ) )
         {
             return JaxenConstants.EMPTY_ITERATOR;
         }
 
         Element elem = (Element) contextNode;
 
         return elem.getAttributes().iterator();
     }
 
     /**
      * 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;
             Namespace namespace = (namespaceURI == null ? Namespace.NO_NAMESPACE : 
                                     Namespace.getNamespace(namespacePrefix, namespaceURI));
             Attribute attr = node.getAttribute(localName, namespace);
             if (attr != null) {
                 return new SingleObjectIterator(attr);
             }
         }
         return JaxenConstants.EMPTY_ITERATOR;
     }
 
     /** Returns a parsed form of the given XPath string, which will be suitable
      *  for queries on JDOM documents.
      */
     public XPath parseXPath (String xpath) throws SAXPathException
     {
         return new JDOMXPath(xpath);
     }
 
     public Object getDocumentNode(Object contextNode)
     {
         if ( contextNode instanceof Document )
         {
             return contextNode;
         }
 
         Element elem = (Element) contextNode;
 
         return elem.getDocument();
     }
 
     public String getElementQName(Object obj)
     {
         Element elem = (Element) obj;
 
         String prefix = elem.getNamespacePrefix();
 
         if ( prefix == null || prefix.length() == 0 )
         {
             return elem.getName();
         }
 
         return prefix + ":" + elem.getName();
     }
 
     public String getAttributeQName(Object obj)
     {
         Attribute attr = (Attribute) obj;
 
         String prefix = attr.getNamespacePrefix();
 
         if ( prefix == null || "".equals( prefix ) )
         {
             return attr.getName();
         }
 
         return prefix + ":" + attr.getName();
     }
 
     public String getNamespaceStringValue(Object obj)
     {
         if (obj instanceof Namespace) {
 
             Namespace ns = (Namespace) obj;
             return ns.getURI();
         } else {
 
             XPathNamespace ns = (XPathNamespace) obj;
             return ns.getJDOMNamespace().getURI();
         }
         
     }
 
     public String getNamespacePrefix(Object obj)
     {
         if (obj instanceof Namespace) {
 
             Namespace ns = (Namespace) obj;
             return ns.getPrefix();
         } else {
 
             XPathNamespace ns = (XPathNamespace) obj;
             return ns.getJDOMNamespace().getPrefix();
         }
     }
 
     public String getTextStringValue(Object obj)
     {
         if ( obj instanceof Text )
         {
             return ((Text)obj).getText();
         }
 
         if ( obj instanceof CDATA )
         {
             return ((CDATA)obj).getText();
         }
 
         return "";
     }
 
     public String getAttributeStringValue(Object obj)
     {
         Attribute attr = (Attribute) obj;
 
         return attr.getValue();
     }
 
     public String getElementStringValue(Object obj)
     {
         Element elem = (Element) obj;
 
         StringBuffer buf = new StringBuffer();
 
         List     content     = elem.getContent();
         Iterator contentIter = content.iterator();
         Object   each        = null;
 
         while ( contentIter.hasNext() )
         {
             each = contentIter.next();
 
             if ( each instanceof Text )
             {
                 buf.append( ((Text)each).getText() );
             }
             else if ( each instanceof CDATA )
             {
                 buf.append( ((CDATA)each).getText() );
             }
             else if ( each instanceof Element )
             {
                 buf.append( getElementStringValue( each ) );
             }
         }
 
         return buf.toString();
     }
 
     public String getProcessingInstructionTarget(Object obj)
     {
         ProcessingInstruction pi = (ProcessingInstruction) obj;
 
         return pi.getTarget();
     }
 
     public String getProcessingInstructionData(Object obj)
     {
         ProcessingInstruction pi = (ProcessingInstruction) obj;
 
         return pi.getData();
     }
 
     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 Text )
         {
             element = (Element)((Text)context).getParent();
         }
         else if ( context instanceof Attribute )
         {
             element = ((Attribute)context).getParent();
         }
         else if ( context instanceof XPathNamespace )
         {
             element = ((XPathNamespace)context).getJDOMElement();
         }
         else if ( context instanceof Comment )
         {
             element = (Element)((Comment)context).getParent();
         }
         else if ( context instanceof ProcessingInstruction )
         {
             element = (Element)((ProcessingInstruction)context).getParent();
         }
 
         if ( element != null )
         {
             Namespace namespace = element.getNamespace( prefix );
 
             if ( namespace != null ) 
             {
                 return namespace.getURI();
             }
         }
         return null;
     }
 
     public Object getDocument(String url) throws FunctionCallException
     {
         try
         {
             SAXBuilder builder = new SAXBuilder();
             
             return builder.build( url );
         }
         catch (Exception e)
         {
             throw new FunctionCallException( e.getMessage() );
         }
     }
 }