/*
    * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
    *
    * This software is open source.
    * See the bottom of this file for the licence.
    */
   
   package org.dom4j;
   
  import org.dom4j.tree.AbstractNode;
  import org.dom4j.tree.DefaultNamespace;
  import org.dom4j.tree.NamespaceCache;
  
  /***
   * <p>
   * <code>Namespace</code> is a Flyweight Namespace that can be shared amongst
   * nodes.
   * </p>
   * 
   * @author <a href="mailto:jstrachan@apache.org">James Strachan </a>
   * @version $Revision: 1.22 $
   */
  public class Namespace extends AbstractNode {
      /*** Cache of Namespace instances */
      protected static final NamespaceCache CACHE = new NamespaceCache();
  
      /*** XML Namespace */
      public static final Namespace XML_NAMESPACE = CACHE.get("xml",
              "http://www.w3.org/XML/1998/namespace");
  
      /*** No Namespace present */
      public static final Namespace NO_NAMESPACE = CACHE.get("", "");
  
      /*** The prefix mapped to this namespace */
      private String prefix;
  
      /*** The URI for this namespace */
      private String uri;
  
      /*** A cached version of the hashcode for efficiency */
      private int hashCode;
  
      /***
       * DOCUMENT ME!
       * 
       * @param prefix
       *            is the prefix for this namespace
       * @param uri
       *            is the URI for this namespace
       */
      public Namespace(String prefix, String uri) {
          this.prefix = (prefix != null) ? prefix : "";
          this.uri = (uri != null) ? uri : "";
      }
  
      /***
       * A helper method to return the Namespace instance for the given prefix and
       * URI
       * 
       * @param prefix
       *            DOCUMENT ME!
       * @param uri
       *            DOCUMENT ME!
       * 
       * @return an interned Namespace object
       */
      public static Namespace get(String prefix, String uri) {
          return CACHE.get(prefix, uri);
      }
  
      /***
       * A helper method to return the Namespace instance for no prefix and the
       * URI
       * 
       * @param uri
       *            DOCUMENT ME!
       * 
       * @return an interned Namespace object
       */
      public static Namespace get(String uri) {
          return CACHE.get(uri);
      }
  
      public short getNodeType() {
          return NAMESPACE_NODE;
      }
  
      /***
       * DOCUMENT ME!
       * 
       * @return the hash code based on the qualified name and the URI of the
       *         namespace.
       */
      public int hashCode() {
          if (hashCode == 0) {
              hashCode = createHashCode();
          }
  
          return hashCode;
     }
 
     /***
      * Factory method to create the hashcode allowing derived classes to change
      * the behaviour
      * 
      * @return DOCUMENT ME!
      */
     protected int createHashCode() {
         int result = uri.hashCode() ^ prefix.hashCode();
 
         if (result == 0) {
             result = 0xbabe;
         }
 
         return result;
     }
 
     /***
      * Checks whether this Namespace equals the given Namespace. Two Namespaces
      * are equals if their URI and prefix are equal.
      * 
      * @param object
      *            DOCUMENT ME!
      * 
      * @return DOCUMENT ME!
      */
     public boolean equals(Object object) {
         if (this == object) {
             return true;
         } else if (object instanceof Namespace) {
             Namespace that = (Namespace) object;
 
             // we cache hash codes so this should be quick
             if (hashCode() == that.hashCode()) {
                 return uri.equals(that.getURI())
                         && prefix.equals(that.getPrefix());
             }
         }
 
         return false;
     }
 
     public String getText() {
         return uri;
     }
 
     public String getStringValue() {
         return uri;
     }
 
     /***
      * DOCUMENT ME!
      * 
      * @return the prefix for this <code>Namespace</code>.
      */
     public String getPrefix() {
         return prefix;
     }
 
     /***
      * DOCUMENT ME!
      * 
      * @return the URI for this <code>Namespace</code>.
      */
     public String getURI() {
         return uri;
     }
 
     public String getXPathNameStep() {
         if ((prefix != null) && !"".equals(prefix)) {
             return "namespace::" + prefix;
         }
 
         return "namespace::*[name()='']";
     }
 
     public String getPath(Element context) {
         StringBuffer path = new StringBuffer(10);
         Element parent = getParent();
 
         if ((parent != null) && (parent != context)) {
             path.append(parent.getPath(context));
             path.append('/');
         }
 
         path.append(getXPathNameStep());
 
         return path.toString();
     }
 
     public String getUniquePath(Element context) {
         StringBuffer path = new StringBuffer(10);
         Element parent = getParent();
 
         if ((parent != null) && (parent != context)) {
             path.append(parent.getUniquePath(context));
             path.append('/');
         }
 
         path.append(getXPathNameStep());
 
         return path.toString();
     }
 
     public String toString() {
         return super.toString() + " [Namespace: prefix " + getPrefix()
                 + " mapped to URI \"" + getURI() + "\"]";
     }
 
     public String asXML() {
         StringBuffer asxml = new StringBuffer(10);
         String pref = getPrefix();
 
         if ((pref != null) && (pref.length() > 0)) {
             asxml.append("xmlns:");
             asxml.append(pref);
             asxml.append("=\"");
         } else {
             asxml.append("xmlns=\"");
         }
 
         asxml.append(getURI());
         asxml.append("\"");
 
         return asxml.toString();
     }
 
     public void accept(Visitor visitor) {
         visitor.visit(this);
     }
 
     protected Node createXPathResult(Element parent) {
         return new DefaultNamespace(parent, getPrefix(), getURI());
     }
 }
 
 /*
  * Redistribution and use of this software and associated documentation
  * ("Software"), with or without modification, are permitted provided that the
  * following conditions are met:
  * 
  * 1. Redistributions of source code must retain copyright statements and
  * notices. Redistributions must also contain a copy of this document.
  * 
  * 2. 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.
  * 
  * 3. The name "DOM4J" must not be used to endorse or promote products derived
  * from this Software without prior written permission of MetaStuff, Ltd. For
  * written permission, please contact dom4j-info@metastuff.com.
  * 
  * 4. Products derived from this Software may not be called "DOM4J" nor may
  * "DOM4J" appear in their names without prior written permission of MetaStuff,
  * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
  * 
  * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
  * 
  * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESSED 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 METASTUFF, LTD. OR ITS 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.
  * 
  * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
  */