nodesequence.java

来自「java jdk 1.4的源码」· Java 代码 · 共 686 行 · 第 1/2 页

    	m_next++;
    }
    	
    return next;
  }

  /**
   * @see DTMIterator#previousNode()
   */
  public int previousNode()
  {
  	if(hasCache())
  	{
  		if(m_next <= 0)
  			return DTM.NULL;
  		else
  		{
  			m_next--;
  			return item(m_next);
  		}
  	}
  	else
  	{
	    int n = m_iter.previousNode();
	    m_next = m_iter.getCurrentPos();
	    return m_next;
  	}
  }

  /**
   * @see DTMIterator#detach()
   */
  public void detach()
  {
  	if(null != m_iter)
  		m_iter.detach();
  	super.detach();
  }

  /**
   * Calling this with a value of false will cause the nodeset 
   * to be cached.
   * @see DTMIterator#allowDetachToRelease(boolean)
   */
  public void allowDetachToRelease(boolean allowRelease)
  {
  	if((false == allowRelease) && !hasCache())
  	{
  		setShouldCacheNodes(true);
  	}
  	
  	if(null != m_iter)
  		m_iter.allowDetachToRelease(allowRelease);
  	super.allowDetachToRelease(allowRelease);
  }

  /**
   * @see DTMIterator#getCurrentNode()
   */
  public int getCurrentNode()
  {
  	if(hasCache())
  	{
  		int currentIndex = m_next-1;
  		NodeVector vec = getVector();
  		if((currentIndex >= 0) && (currentIndex < vec.size()))
  			return vec.elementAt(currentIndex);
  		else
  			return DTM.NULL;
  	}
  	
  	if(null != m_iter)
  	{
    	return m_iter.getCurrentNode();
  	}
  	else
  		return DTM.NULL;
  }

  /**
   * @see DTMIterator#isFresh()
   */
  public boolean isFresh()
  {
    return (0 == m_next);
  }

  /**
   * @see DTMIterator#setShouldCacheNodes(boolean)
   */
  public void setShouldCacheNodes(boolean b)
  {
    if (b)
    {
      if(!hasCache())
      {
        SetVector(new NodeVector());
      }
//	  else
//	    getVector().RemoveAllNoClear();  // Is this good?
    }
    else
      SetVector(null);
  }

  /**
   * @see DTMIterator#isMutable()
   */
  public boolean isMutable()
  {
    return hasCache(); // though may be surprising if it also has an iterator!
  }

  /**
   * @see DTMIterator#getCurrentPos()
   */
  public int getCurrentPos()
  {
    return m_next;
  }

  /**
   * @see DTMIterator#runTo(int)
   */
  public void runTo(int index)
  {
    int n;
    
    if (-1 == index)
    {
      int pos = m_next;
      while (DTM.NULL != (n = nextNode()));
      m_next = pos;
    }
    else if(m_next == index)
    {
      return;
    }
    else if(hasCache() && m_next < getVector().size())
    {
      m_next = index;
    }
    else if((null == getVector()) && (index < m_next))
    {
      while ((m_next >= index) && DTM.NULL != (n = previousNode()));
    }
    else
    {   
      while ((m_next < index) && DTM.NULL != (n = nextNode()));
    }
    
  }

  /**
   * @see DTMIterator#setCurrentPos(int)
   */
  public void setCurrentPos(int i)
  {
  	runTo(i);
  }

  /**
   * @see DTMIterator#item(int)
   */
  public int item(int index)
  {
  	setCurrentPos(index);
  	int n = nextNode();
  	m_next = index;
  	return n;
  }

  /**
   * @see DTMIterator#setItem(int, int)
   */
  public void setItem(int node, int index)
  {
  	NodeVector vec = getVector();
  	if(null != vec)
  	{
  		vec.setElementAt(node, index);
  		m_last = vec.size();
  	}
  	else
  		m_iter.setItem(node, index);
  }

  /**
   * @see DTMIterator#getLength()
   */
  public int getLength()
  {
  	if(hasCache())
  	{
        // If this NodeSequence wraps a mutable nodeset, then
        // m_last will not reflect the size of the nodeset if
        // it has been mutated...
        if (m_iter instanceof NodeSetDTM)
        {
            return m_iter.getLength();
        }    
        
	  	if(-1 == m_last)
	  	{
	  		int pos = m_next;
	  		runTo(-1);
	  		m_next = pos;
	  	}
	    return m_last;
  	}
  	else
  	{
  		return (-1 == m_last) ? (m_last = m_iter.getLength()) : m_last;
  	}
  }

  /**
   * Note: Not a deep clone.
   * @see DTMIterator#cloneWithReset()
   */
  public DTMIterator cloneWithReset() throws CloneNotSupportedException
  {
  	NodeSequence seq = (NodeSequence)super.clone();
    seq.m_next = 0;
    return seq;
  }
  
  /**
   * Get a clone of this iterator, but don't reset the iteration in the 
   * process, so that it may be used from the current position.
   * Note: Not a deep clone.
   *
   * @return A clone of this object.
   *
   * @throws CloneNotSupportedException
   */
  public Object clone() throws CloneNotSupportedException
  {
  	return super.clone();
  }


  /**
   * @see DTMIterator#isDocOrdered()
   */
  public boolean isDocOrdered()
  {
  	if(null != m_iter)
  		return m_iter.isDocOrdered();
  	else
    	return true; // can't be sure?
  }

  /**
   * @see DTMIterator#getAxis()
   */
  public int getAxis()
  {
  	if(null != m_iter)
    	return m_iter.getAxis();
    else
    {
    	assertion(false, "Can not getAxis from a non-iterated node sequence!");
    	return 0;
    }
  }

  /**
   * @see PathComponent#getAnalysisBits()
   */
  public int getAnalysisBits()
  {
  	if((null != m_iter) && (m_iter instanceof PathComponent))
    	return ((PathComponent)m_iter).getAnalysisBits();
    else
    	return 0;
  }

  /**
   * @see Expression#fixupVariables(Vector, int)
   */
  public void fixupVariables(Vector vars, int globalsSize)
  {
  	super.fixupVariables(vars, globalsSize);
  }  
  
  /**
   * Add the node into a vector of nodes where it should occur in
   * document order.
   * @param v Vector of nodes, presumably containing Nodes
   * @param obj Node object.
   *
   * @param node The node to be added.
   * @param test true if we should test for doc order
   * @param support The XPath runtime context.
   * @return insertIndex.
   * @throws RuntimeException thrown if this NodeSetDTM is not of 
   * a mutable type.
   */
   protected int addNodeInDocOrder(int node)
   {
      assertion(hasCache(), "addNodeInDocOrder must be done on a mutable sequence!");

      int insertIndex = -1;
      
      NodeVector vec = getVector();

      // This needs to do a binary search, but a binary search 
      // is somewhat tough because the sequence test involves 
      // two nodes.
      int size = vec.size(), i;

      for (i = size - 1; i >= 0; i--)
      {
        int child = vec.elementAt(i);

        if (child == node)
        {
          i = -2; // Duplicate, suppress insert

          break;
        }

        DTM dtm = m_dtmMgr.getDTM(node);
        if (!dtm.isNodeAfter(node, child))
        {
          break;
        }
      }

      if (i != -2)
      {
        insertIndex = i + 1;

        vec.insertElementAt(node, insertIndex);
      }

      // checkDups();
      return insertIndex;
    } // end addNodeInDocOrder(Vector v, Object obj)
}