code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the  "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * $Id$
   */
  package org.apache.xpath.objects;
  
  import org.apache.xml.dtm.DTM;
  import org.apache.xml.dtm.DTMIterator;
  import org.apache.xml.dtm.DTMManager;
  import org.apache.xml.utils.XMLString;
  import org.apache.xpath.NodeSetDTM;
  import org.apache.xpath.axes.NodeSequence;
  
  import org.w3c.dom.NodeList;
  import org.w3c.dom.traversal.NodeIterator;
  
  /**
   * This class represents an XPath nodeset object, and is capable of
   * converting the nodeset to other types, such as a string.
   * @xsl.usage general
   */
  public class XNodeSet extends NodeSequence
  {  
      static final long serialVersionUID = 1916026368035639667L;
    /**
     * 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)
    	{
          final XNodeSet nodeSet = (XNodeSet) val;
  	    setIter(nodeSet.m_iter);
  	    m_dtmMgr = nodeSet.m_dtmMgr;
  	    m_last = nodeSet.m_last;
          // First make sure the DTMIterator val has a cache,
          // so if it doesn't have one, make one.
  	    if(!nodeSet.hasCache())
  	        nodeSet.setShouldCacheNodes(true);
          
          // Get the cache from val and use it ourselves (we share it).
  	    setObject(nodeSet.getIteratorCache());
    	}
    	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);
      setObject(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) 
    {
       this(DTM.NULL,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
    {
      org.apache.xml.dtm.ref.DTMNodeList nodelist = new org.apache.xml.dtm.ref.DTMNodeList(this);
      // Creating a DTMNodeList has the side-effect that it will create a clone
      // XNodeSet with cache and run m_iter to the end. You cannot get any node
      // from m_iter after this call. As a fix, we call SetVector() on the clone's 
      // cache. See Bugzilla 14406.
      XNodeSet clone = (XNodeSet)nodelist.getDTMIterator();
      SetVector(clone.getVector());
      return nodelist;
    }
  
    
  //  /**
  //   * 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());
        setObject(mnl);
        setCurrentPos(0);
      }
  
      return mnl;
    }
  
    /** Less than comparator         */
    static final LessThanComparator S_LT = new LessThanComparator();
  
    /** Less than or equal comparator          */
    static final LessThanOrEqualComparator S_LTE = new LessThanOrEqualComparator();
  
    /** Greater than comparator         */
    static final GreaterThanComparator S_GT = new GreaterThanComparator();
  
    /** Greater than or equal comparator          */
    static final GreaterThanOrEqualComparator S_GTE =
      new GreaterThanOrEqualComparator();
  
    /** Equal comparator         */
    static final EqualComparator S_EQ = new EqualComparator();
  
    /** Not equal comparator         */
    static final 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
     */
    public boolean compare(XObject obj2, Comparator comparator)
            throws javax.xml.transform.TransformerException
    {
  
      boolean result = false;
      int type = obj2.getType();
  
      if (XObject.CLASS_NODESET == type)
      {
        // %OPT% This should be XMLString based instead of string based...
  
        // From http://www.w3.org/TR/xpath: 
        // If both objects to be compared are node-sets, then the comparison 
        // will be true if and only if there is a node in the first node-set 
        // and a node in the second node-set such that the result of performing 
        // the comparison on the string-values of the two nodes is true.
        // Note this little gem from the draft:
        // NOTE: If $x is bound to a node-set, then $x="foo" 
        // does not mean the same as not($x!="foo"): the former 
        // is true if and only if some node in $x has the string-value 
        // foo; the latter is true if and only if all nodes in $x have 
        // the string-value foo.
        DTMIterator list1 = iterRaw();
        DTMIterator list2 = ((XNodeSet) obj2).iterRaw();
        int node1;
        java.util.Vector node2Strings = null;
  
        while (DTM.NULL != (node1 = list1.nextNode()))
        {
          XMLString s1 = getStringFromNode(node1);
  
          if (null == node2Strings)
          {
            int node2;
  
            while (DTM.NULL != (node2 = list2.nextNode()))
            {
              XMLString s2 = getStringFromNode(node2);
  
              if (comparator.compareStrings(s1, s2))
              {
                result = true;
  
                break;
              }
  
              if (null == node2Strings)
                node2Strings = new java.util.Vector();
  
              node2Strings.addElement(s2);
            }
          }
          else
          {
            int n = node2Strings.size();
  
            for (int i = 0; i < n; i++)
            {
              if (comparator.compareStrings(s1, (XMLString)node2Strings.elementAt(i)))
              {
                result = true;
  
                break;
              }
            }
          }
        }
        list1.reset();
        list2.reset();
      }
      else if (XObject.CLASS_BOOLEAN == type)
      {
  
        // From http://www.w3.org/TR/xpath: 
        // If one object to be compared is a node-set and the other is a boolean, 
        // then the comparison will be true if and only if the result of 
        // performing the comparison on the boolean and on the result of 
        // converting the node-set to a boolean using the boolean function 
        // is true.
        double num1 = bool() ? 1.0 : 0.0;
        double num2 = obj2.num();
  
        result = comparator.compareNumbers(num1, num2);
      }
      else if (XObject.CLASS_NUMBER == type)
      {
  
        // From http://www.w3.org/TR/xpath: 
        // If one object to be compared is a node-set and the other is a number, 
        // then the comparison will be true if and only if there is a 
        // node in the node-set such that the result of performing the 
        // comparison on the number to be compared and on the result of 
        // converting the string-value of that node to a number using 
        // the number function is true. 
        DTMIterator list1 = iterRaw();
        double num2 = obj2.num();
        int node;
  
        while (DTM.NULL != (node = list1.nextNode()))
        {
          double num1 = getNumberFromNode(node);
  
          if (comparator.compareNumbers(num1, num2))
          {
            result = true;
  
            break;
          }
        }
        list1.reset();
      }
      else if (XObject.CLASS_RTREEFRAG == type)
      {
        XMLString s2 = obj2.xstr();
        DTMIterator list1 = iterRaw();
        int node;
  
        while (DTM.NULL != (node = list1.nextNode()))
        {
          XMLString s1 = getStringFromNode(node);
  
          if (comparator.compareStrings(s1, s2))
          {
            result = true;
  
            break;
          }
        }
        list1.reset();
      }
      else if (XObject.CLASS_STRING == type)
      {
  
        // From http://www.w3.org/TR/xpath: 
        // If one object to be compared is a node-set and the other is a 
        // string, then the comparison will be true if and only if there 
        // is a node in the node-set such that the result of performing 
        // the comparison on the string-value of the node and the other 
        // string is true. 
        XMLString s2 = obj2.xstr();
        DTMIterator list1 = iterRaw();
        int node;
  
        while (DTM.NULL != (node = list1.nextNode()))
        {
          XMLString s1 = getStringFromNode(node);
          if (comparator.compareStrings(s1, s2))
          {
            result = true;
  
            break;
          }
        }
        list1.reset();
      }
      else
      {
        result = comparator.compareNumbers(this.num(), obj2.num());
      }
  
      return result;
    }
  
    /**
     * Tell if one object is less than the other.
     *
     * @param obj2 object to compare this nodeset to
     *
     * @return see this.compare(...) 
     *
     * @throws javax.xml.transform.TransformerException
     */
    public boolean lessThan(XObject obj2) throws javax.xml.transform.TransformerException
    {
      return compare(obj2, S_LT);
    }
  
    /**
     * Tell if one object is less than or equal to the other.
     *
     * @param obj2 object to compare this nodeset to
     *
     * @return see this.compare(...) 
     *
     * @throws javax.xml.transform.TransformerException
     */
    public boolean lessThanOrEqual(XObject obj2) throws javax.xml.transform.TransformerException
    {
      return compare(obj2, S_LTE);
    }
  
    /**
     * Tell if one object is less than the other.
     *
     * @param obj2 object to compare this nodeset to
     *
     * @return see this.compare(...) 
     *
     * @throws javax.xml.transform.TransformerException
     */
    public boolean greaterThan(XObject obj2) throws javax.xml.transform.TransformerException
    {
      return compare(obj2, S_GT);
    }
  
    /**
     * Tell if one object is less than the other.
     *
     * @param obj2 object to compare this nodeset to
     *
     * @return see this.compare(...) 
     *
     * @throws javax.xml.transform.TransformerException
     */
    public boolean greaterThanOrEqual(XObject obj2)
            throws javax.xml.transform.TransformerException
    {
      return compare(obj2, S_GTE);
    }
  
    /**
     * Tell if two objects are functionally equal.
     *
     * @param obj2 object to compare this nodeset to
     *
     * @return see this.compare(...) 
     *
     * @throws javax.xml.transform.TransformerException
     */
    public boolean equals(XObject obj2)
    {
      try
      {
        return compare(obj2, S_EQ);
      }
      catch(javax.xml.transform.TransformerException te)
      {
        throw new org.apache.xml.utils.WrappedRuntimeException(te);
      }
    }
  
    /**
     * Tell if two objects are functionally not equal.
     *
     * @param obj2 object to compare this nodeset to
     *
     * @return see this.compare(...) 
     *
     * @throws javax.xml.transform.TransformerException
     */
    public boolean notEquals(XObject obj2) throws javax.xml.transform.TransformerException
    {
      return compare(obj2, S_NEQ);
    }
  }
  
  /**
   * compares nodes for various boolean operations.
   */
  abstract class Comparator
  {
  
    /**
     * Compare two strings
     *
     *
     * @param s1 First string to compare
     * @param s2 Second String to compare 
     *
     * @return Whether the strings are equal or not
     */
    abstract boolean compareStrings(XMLString s1, XMLString s2);
  
    /**
     * Compare two numbers
     *
     *
     * @param n1 First number to compare
     * @param n2 Second number to compare
     *
     * @return Whether the numbers are equal or not
     */
    abstract boolean compareNumbers(double n1, double n2);
  }
  
  /**
   * Compare strings or numbers for less than.
   */
  class LessThanComparator extends Comparator
  {
  
    /**
     * Compare two strings for less than.
     *
     *
     * @param s1 First string to compare
     * @param s2 Second String to compare 
     *
     * @return True if s1 is less than s2
     */
    boolean compareStrings(XMLString s1, XMLString s2)
    {
      return (s1.toDouble() < s2.toDouble());
      // return s1.compareTo(s2) < 0;
    }
  
    /**
     * Compare two numbers for less than.
     *
     *
     * @param n1 First number to compare
     * @param n2 Second number to compare
     *
     * @return true if n1 is less than n2
     */
    boolean compareNumbers(double n1, double n2)
    {
      return n1 < n2;
    }
  }
  
  /**
   * Compare strings or numbers for less than or equal.
   */
  class LessThanOrEqualComparator extends Comparator
  {
  
    /**
     * Compare two strings for less than or equal.
     *
     *
     * @param s1 First string to compare
     * @param s2 Second String to compare
     *
     * @return true if s1 is less than or equal to s2
     */
    boolean compareStrings(XMLString s1, XMLString s2)
    {
      return (s1.toDouble() <= s2.toDouble());
      // return s1.compareTo(s2) <= 0;
    }
  
    /**
     * Compare two numbers for less than or equal.
     *
     *
     * @param n1 First number to compare
     * @param n2 Second number to compare
     *
     * @return true if n1 is less than or equal to n2
     */
    boolean compareNumbers(double n1, double n2)
    {
      return n1 <= n2;
    }
  }
  
  /**
   * Compare strings or numbers for greater than.
   */
  class GreaterThanComparator extends Comparator
  {
  
    /**
     * Compare two strings for greater than.
     *
     *
     * @param s1 First string to compare
     * @param s2 Second String to compare
     *
     * @return true if s1 is greater than s2
     */
    boolean compareStrings(XMLString s1, XMLString s2)
    {
      return (s1.toDouble() > s2.toDouble());
      // return s1.compareTo(s2) > 0;
    }
  
    /**
     * Compare two numbers for greater than.
     *
     *
     * @param n1 First number to compare
     * @param n2 Second number to compare
     *
     * @return true if n1 is greater than n2
     */
    boolean compareNumbers(double n1, double n2)
    {
      return n1 > n2;
    }
  }
  
  /**
   * Compare strings or numbers for greater than or equal.
   */
  class GreaterThanOrEqualComparator extends Comparator
  {
  
    /**
     * Compare two strings for greater than or equal.
     *
     *
     * @param s1 First string to compare
     * @param s2 Second String to compare
     *
     * @return true if s1 is greater than or equal to s2
     */
    boolean compareStrings(XMLString s1, XMLString s2)
    {
      return (s1.toDouble() >= s2.toDouble());
      // return s1.compareTo(s2) >= 0;
    }
  
    /**
     * Compare two numbers for greater than or equal.
     *
     *
     * @param n1 First number to compare
     * @param n2 Second number to compare
     *
     * @return true if n1 is greater than or equal to n2
     */
    boolean compareNumbers(double n1, double n2)
    {
      return n1 >= n2;
    }
  }
  
  /**
   * Compare strings or numbers for equality.
   */
  class EqualComparator extends Comparator
  {
  
    /**
     * Compare two strings for equality.
     *
     *
     * @param s1 First string to compare
     * @param s2 Second String to compare
     *
     * @return true if s1 is equal to s2
     */
    boolean compareStrings(XMLString s1, XMLString s2)
    {
      return s1.equals(s2);
    }
  
    /**
     * Compare two numbers for equality.
     *
     *
     * @param n1 First number to compare
     * @param n2 Second number to compare
     *
     * @return true if n1 is equal to n2
     */
    boolean compareNumbers(double n1, double n2)
    {
      return n1 == n2;
    }
  }
  
  /**
   * Compare strings or numbers for non-equality.
   */
  class NotEqualComparator extends Comparator
  {
  
    /**
     * Compare two strings for non-equality.
     *
     *
     * @param s1 First string to compare
     * @param s2 Second String to compare
     *
     * @return true if s1 is not equal to s2
     */
    boolean compareStrings(XMLString s1, XMLString s2)
    {
      return !s1.equals(s2);
    }
  
    /**
     * Compare two numbers for non-equality.
     *
     *
     * @param n1 First number to compare
     * @param n2 Second number to compare
     *
     * @return true if n1 is not equal to n2
     */
    boolean compareNumbers(double n1, double n2)
    {
      return n1 != n2;
    }
  }
  