xnodeset.java

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/*
 * 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 [e-mail].
 *
 * 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.Node;
//import org.w3c.dom.Text;
//import org.w3c.dom.DocumentFragment;
import org.w3c.dom.traversal.NodeIterator;
import org.w3c.dom.NodeList;

import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMIterator;
import org.apache.xml.dtm.DTMManager;

import org.apache.xpath.DOMHelper;
import org.apache.xpath.XPathContext;
import org.apache.xpath.NodeSetDTM;
import org.apache.xpath.axes.ContextNodeList;
import org.apache.xpath.axes.NodeSequence;
import org.apache.xml.utils.StringVector;
import org.apache.xml.utils.XMLString;

/**
 * <meta name="usage" content="general"/>
 * This class represents an XPath nodeset object, and is capable of
 * converting the nodeset to other types, such as a string.
 */
public class XNodeSet extends NodeSequence
{  
  /**
   * Default constructor for derived objects.
   */
  protected XNodeSet()
  {
  }

  /**
   * Construct a XNodeSet object.
   *
   * @param val Value of the XNodeSet object
   */
  public XNodeSet(DTMIterator val)
  {
  	super();
  	if(val instanceof XNodeSet)
  	{
	    setIter(((XNodeSet)val).m_iter);
	    m_dtmMgr = ((XNodeSet)val).m_dtmMgr;
	    m_last = ((XNodeSet)val).m_last;
	    if(!((XNodeSet)val).hasCache())
	    	((XNodeSet)val).setShouldCacheNodes(true);
	    m_obj = ((XNodeSet)val).m_obj;
  	}
  	else
    	setIter(val);
  }
  
  /**
   * Construct a XNodeSet object.
   *
   * @param val Value of the XNodeSet object
   */
  public XNodeSet(XNodeSet val)
  {
  	super();
    setIter(val.m_iter);
    m_dtmMgr = val.m_dtmMgr;
    m_last = val.m_last;
    if(!val.hasCache())
    	val.setShouldCacheNodes(true);
    m_obj = val.m_obj;
  }


  /**
   * Construct an empty XNodeSet object.  This is used to create a mutable 
   * nodeset to which random nodes may be added.
   */
  public XNodeSet(DTMManager dtmMgr) 
  {
    super(dtmMgr);
  }

  /**
   * Construct a XNodeSet object for one node.
   *
   * @param n Node to add to the new XNodeSet object
   */
  public XNodeSet(int n, DTMManager dtmMgr)
  {

    super(new NodeSetDTM(dtmMgr));
    m_dtmMgr = dtmMgr;

    if (DTM.NULL != n)
    {
      ((NodeSetDTM) m_obj).addNode(n);
      m_last = 1;
    }
    else
    	m_last = 0;
  }

  /**
   * Tell that this is a CLASS_NODESET.
   *
   * @return type CLASS_NODESET
   */
  public int getType()
  {
    return CLASS_NODESET;
  }

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

  /**
   * Get numeric value of the string conversion from a single node.
   *
   * @param n Node to convert
   *
   * @return numeric value of the string conversion from a single node.
   */
  public double getNumberFromNode(int n)
  {
    XMLString xstr = m_dtmMgr.getDTM(n).getStringValue(n);
    return xstr.toDouble();
  }

  /**
   * Cast result object to a number.
   *
   * @return numeric value of the string conversion from the 
   * next node in the NodeSetDTM, or NAN if no node was found
   */
  public double num()
  {

    int node = item(0);
    return (node != DTM.NULL) ? getNumberFromNode(node) : Double.NaN;
  }
  
  /**
   * Cast result object to a number, but allow side effects, such as the 
   * incrementing of an iterator.
   *
   * @return numeric value of the string conversion from the 
   * next node in the NodeSetDTM, or NAN if no node was found
   */
  public double numWithSideEffects()
  {
    int node = nextNode();

    return (node != DTM.NULL) ? getNumberFromNode(node) : Double.NaN;
  }


  /**
   * Cast result object to a boolean.
   *
   * @return True if there is a next node in the nodeset
   */
  public boolean bool()
  {
    return (item(0) != DTM.NULL);
  }
  
  /**
   * Cast result object to a boolean, but allow side effects, such as the 
   * incrementing of an iterator.
   *
   * @return True if there is a next node in the nodeset
   */
  public boolean boolWithSideEffects()
  {
    return (nextNode() != DTM.NULL);
  }

  
  /**
   * Get the string conversion from a single node.
   *
   * @param n Node to convert
   *
   * @return the string conversion from a single node.
   */
  public XMLString getStringFromNode(int n)
  {
    // %OPT%
    // I guess we'll have to get a static instance of the DTM manager...
    if(DTM.NULL != n)
    {
      return m_dtmMgr.getDTM(n).getStringValue(n);
    }
    else
    {
      return org.apache.xpath.objects.XString.EMPTYSTRING;
    }
  }
  
  /**
   * Directly call the
   * characters method on the passed ContentHandler for the
   * string-value. Multiple calls to the
   * ContentHandler's characters methods may well occur for a single call to
   * this method.
   *
   * @param ch A non-null reference to a ContentHandler.
   *
   * @throws org.xml.sax.SAXException
   */
  public void dispatchCharactersEvents(org.xml.sax.ContentHandler ch)
          throws org.xml.sax.SAXException
  {
    int node = item(0);
	
    if(node != DTM.NULL)
    {
      m_dtmMgr.getDTM(node).dispatchCharactersEvents(node, ch, false);
    }
    
  }
  
  /**
   * Cast result object to an XMLString.
   *
   * @return The document fragment node data or the empty string. 
   */
  public XMLString xstr()
  {
    int node = item(0);
    return (node != DTM.NULL) ? getStringFromNode(node) : XString.EMPTYSTRING;
  }
  
  /**
   * Cast result object to a string.
   *
   * @return The string this wraps or the empty string if null
   */
  public void appendToFsb(org.apache.xml.utils.FastStringBuffer fsb)
  {
    XString xstring = (XString)xstr();
    xstring.appendToFsb(fsb);
  }
  

  /**
   * Cast result object to a string.
   *
   * @return the string conversion from the next node in the nodeset
   * or "" if there is no next node
   */
  public String str()
  {
    int node = item(0);
    return (node != DTM.NULL) ? getStringFromNode(node).toString() : "";   
  }
  
  /**
   * Return a java object that's closest to the representation
   * that should be handed to an extension.
   *
   * @return The object that this class wraps
   */
  public Object object()
  {
    if(null == m_obj)
    	return this;
    else
    	return m_obj;
  }

  // %REVIEW%
  // hmmm...
//  /**
//   * Cast result object to a result tree fragment.
//   *
//   * @param support The XPath context to use for the conversion 
//   *
//   * @return the nodeset as a result tree fragment.
//   */
//  public DocumentFragment rtree(XPathContext support)
//  {
//    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
//    DocumentBuilder db = dbf.newDocumentBuilder();
//    Document myDoc = db.newDocument();
//    
//    DocumentFragment docFrag = myDoc.createDocumentFragment();
//
//    DTMIterator nl = iter();
//    int node;
//
//    while (DTM.NULL != (node = nl.nextNode()))
//    {
//      frag.appendChild(node, true, true);
//    }
//
//    return frag.getDocument();
//  }

  /**
   * Cast result object to a nodelist.
   *
   * @return a NodeIterator.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public NodeIterator nodeset() throws javax.xml.transform.TransformerException
  {
    return new org.apache.xml.dtm.ref.DTMNodeIterator(iter());
  }
  
  /**
   * Cast result object to a nodelist.
   *
   * @return a NodeList.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public NodeList nodelist() throws javax.xml.transform.TransformerException
  {
    return new org.apache.xml.dtm.ref.DTMNodeList(iter());
  }

  
//  /**
//   * Return a java object that's closest to the representation
//   * that should be handed to an extension.
//   *
//   * @return The object that this class wraps
//   */
//  public Object object()
//  {
//    return new org.apache.xml.dtm.ref.DTMNodeList(iter());
//  }

  /**
   * Return the iterator without cloning, etc.
   */
  public DTMIterator iterRaw()
  {
    return this;
  }
  
  public void release(DTMIterator iter)
  {
  }
  
  /**
   * Cast result object to a nodelist.
   *
   * @return The nodeset as a nodelist
   */
  public DTMIterator iter()
  {
    try
    {
    	if(hasCache())
      		return cloneWithReset();
      	else
      		return this; // don't bother to clone... won't do any good!
    }
    catch (CloneNotSupportedException cnse)
    {
      throw new RuntimeException(cnse.getMessage());
    }
  }
  
  /**
   * Get a fresh copy of the object.  For use with variables.
   *
   * @return A fresh nodelist.
   */
  public XObject getFresh()
  {
    try
    {
    	if(hasCache())
      		return (XObject)cloneWithReset();
      	else
      		return this; // don't bother to clone... won't do any good!
    }
    catch (CloneNotSupportedException cnse)
    {
      throw new RuntimeException(cnse.getMessage());
    }
  }

  /**
   * Cast result object to a mutableNodeset.
   *
   * @return The nodeset as a mutableNodeset
   */
  public NodeSetDTM mutableNodeset()
  {
    NodeSetDTM mnl;

    if(m_obj instanceof NodeSetDTM)
    {
      mnl = (NodeSetDTM) m_obj;
    }
    else
    {
      mnl = new NodeSetDTM(iter());
      m_obj = mnl;
      setCurrentPos(0);
    }

    return mnl;
  }

  /** Less than comparator         */
  static LessThanComparator S_LT = new LessThanComparator();

  /** Less than or equal comparator          */
  static LessThanOrEqualComparator S_LTE = new LessThanOrEqualComparator();

  /** Greater than comparator         */
  static GreaterThanComparator S_GT = new GreaterThanComparator();

  /** Greater than or equal comparator          */
  static GreaterThanOrEqualComparator S_GTE =
    new GreaterThanOrEqualComparator();

  /** Equal comparator         */
  static EqualComparator S_EQ = new EqualComparator();

  /** Not equal comparator         */
  static NotEqualComparator S_NEQ = new NotEqualComparator();

  /**
   * Tell if one object is less than the other.
   *
   * @param obj2 Object to compare this nodeset to
   * @param comparator Comparator to use
   *
   * @return See the comments below for each object type comparison 
   *
   * @throws javax.xml.transform.TransformerException