/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 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 end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``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 THE APACHE SOFTWARE FOUNDATION 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.xpath.objects;

import org.w3c.dom.*;
import org.w3c.dom.traversal.NodeIterator;
import org.w3c.dom.traversal.NodeFilter;

import org.apache.xpath.DOMHelper;

/**
 * <meta name="usage" content="general"/>
 * This class represents an XPath result tree fragment object, and is capable of
 * converting the RTF to other types, such as a string.
 */
public class XRTreeFrag extends XObject
{

  /**
   * Create an XRTreeFrag Object.
   *
   * @param frag Document fragment this will wrap
   */
  public XRTreeFrag(DocumentFragment frag)
  {
    super(frag);
  }

  /**
   * Tell what kind of class this is.
   *
   * @return type CLASS_RTREEFRAG 
   */
  public int getType()
  {
    return CLASS_RTREEFRAG;
  }

  /**
   * Given a request type, return the equivalent string.
   * For diagnostic purposes.
   *
   * @return type string "#RTREEFRAG"
   */
  public String getTypeString()
  {
    return "#RTREEFRAG";
  }

  /**
   * Cast result object to a number.
   *
   * @return The result tree fragment as a number or NaN
   */
  public double num()
  {

//    java.text.NumberFormat m_formatter =
//      java.text.NumberFormat.getNumberInstance();
    double result;
    String s = DOMHelper.getNodeData((DocumentFragment) m_obj);

    if (null != s)
    {
//      try
//      {

        // result = Double.valueOf(s).doubleValue();
//        Number n = m_formatter.parse(s.trim());
//
//        result = n.doubleValue();
          result = XString.castToNum(s.trim());
//      }
//
//      // catch(NumberFormatException nfe)
//      catch (java.text.ParseException nfe)
//      {
//        result = Double.NaN;
//      }
    }
    else
    {
      result = Double.NaN;
    }

    return result;
  }

  /**
   * Cast result object to a boolean.  This always returns true for a RTreeFrag
   * because it is treated like a node-set with a single root node.
   *
   * @return true
   */
  public boolean bool()
  {
    return true;
  }

  /**
   * Cast result object to a string.
   *
   * @return The document fragment node data or the empty string. 
   */
  public String str()
  {

    String str = DOMHelper.getNodeData((DocumentFragment) m_obj);

    return (null == str) ? "" : str;
  }

  /**
   * Cast result object to a result tree fragment.
   *
   * @return The document fragment this wraps
   */
  public DocumentFragment rtree()
  {
    return (DocumentFragment) m_obj;
  }

  /**
   * Cast result object to a NodeIterator.
   *
   * @return The document fragment as a NodeIterator
   */
  public NodeIterator asNodeIterator()
  {

    if (m_obj instanceof NodeIterator)
      return (NodeIterator) m_obj;
    else
      return new NodeIteratorWrapper(rtree());
  }

  /**
   * Cast result object to a nodelist. (special function).
   *
   * @return The document fragment as a nodelist
   */
  public NodeList convertToNodeset()
  {

    if (m_obj instanceof NodeList)
      return (NodeList) m_obj;
    else
      return null;
  }

  /**
   * Tell if two objects are functionally equal.
   *
   * @param obj2 Object to compare this to
   *
   * @return True if the two objects are equal
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean equals(XObject obj2) throws javax.xml.transform.TransformerException
  {

    if (XObject.CLASS_NODESET == obj2.getType())
    {

      // In order to handle the 'all' semantics of 
      // nodeset comparisons, we always call the 
      // nodeset function.
      return obj2.equals(this);
    }
    else if (XObject.CLASS_BOOLEAN == obj2.getType())
    {
      return bool() == obj2.bool();
    }
    else if (XObject.CLASS_NUMBER == obj2.getType())
    {
      return num() == obj2.num();
    }
    else if (XObject.CLASS_NODESET == obj2.getType())
    {
      return str().equals(obj2.str());
    }
    else if (XObject.CLASS_STRING == obj2.getType())
    {
      return str().equals(obj2.str());
    }
    else if (XObject.CLASS_RTREEFRAG == obj2.getType())
    {

      // Probably not so good.  Think about this.
      return str().equals(obj2.str());
    }
    else
    {
      return super.equals(obj2);
    }
  }

  /**
   * <meta name="usage" content="internal"/>
   * Class to wrap a  NodeIterator object
   */
  class NodeIteratorWrapper implements NodeIterator
  {

    /** Position of next node          */
    private int m_pos = -1;

    /** Document fragment instance this will wrap         */
    private DocumentFragment m_docFrag;

    /**
     * Constructor NodeIteratorWrapper
     *
     *
     * @param df Document fragment instance this will wrap
     */
    NodeIteratorWrapper(DocumentFragment df)
    {
      m_docFrag = df;
    }

    /**
     *  The root node of the Iterator, as specified when it was created.
     *
     * @return null
     */
    public Node getRoot()
    {
      return null;
    }

    /**
     *  This attribute determines which node types are presented via the
     * iterator. The available set of constants is defined in the
     * <code>NodeFilter</code> interface.
     *
     * @return All node types
     */
    public int getWhatToShow()
    {
      return NodeFilter.SHOW_ALL;
    }

    /**
     *  The filter used to screen nodes.
     *
     * @return null
     */
    public NodeFilter getFilter()
    {
      return null;
    }

    /**
     *  The value of this flag determines whether the children of entity
     * reference nodes are visible to the iterator. If false, they will be
     * skipped over.
     * <br> To produce a view of the document that has entity references
     * expanded and does not expose the entity reference node itself, use the
     * whatToShow flags to hide the entity reference node and set
     * expandEntityReferences to true when creating the iterator. To produce
     * a view of the document that has entity reference nodes but no entity
     * expansion, use the whatToShow flags to show the entity reference node
     * and set expandEntityReferences to false.
     *
     * @return true
     */
    public boolean getExpandEntityReferences()
    {
      return true;
    }

    /**
     *  Returns the next node in the set and advances the position of the
     * iterator in the set. After a NodeIterator is created, the first call
     * to nextNode() returns the first node in the set.
     * @return  The next <code>Node</code> in the set being iterated over, or
     *   <code>null</code> if there are no more members in that set.
     * @throws DOMException
     *    INVALID_STATE_ERR: Raised if this method is called after the
     *   <code>detach</code> method was invoked.
     */
    public Node nextNode() throws DOMException
    {

      if (-1 == m_pos)
      {
        m_pos = 0;

        return m_docFrag;
      }
      else
        return null;
    }

    /**
     *  Returns the previous node in the set and moves the position of the
     * iterator backwards in the set.
     * @return  The previous <code>Node</code> in the set being iterated over,
     *   or<code>null</code> if there are no more members in that set.
     * @throws DOMException
     *    INVALID_STATE_ERR: Raised if this method is called after the
     *   <code>detach</code> method was invoked.
     */
    public Node previousNode() throws DOMException
    {

      if (0 == m_pos)
      {
        m_pos = -1;

        return m_docFrag;
      }
      else
        return null;
    }

    /**
     *  Detaches the iterator from the set which it iterated over, releasing
     * any computational resources and placing the iterator in the INVALID
     * state. After<code>detach</code> has been invoked, calls to
     * <code>nextNode</code> or<code>previousNode</code> will raise the
     * exception INVALID_STATE_ERR.
     */
    public void detach(){}
  }
}