dtmdefaultbasetraversers.java

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     * @param expandedTypeID The expanded type ID that must match.
     *
     * @return the first node in the traversal.
     */
    public int first(int context, int expandedTypeID)
    {
			// %REVIEW% This looks like it might want shift into identity space
			// to avoid repeated conversion in the individual functions
      int first;
      int type = getNodeType(context);

      if ((DTM.ATTRIBUTE_NODE == type) || (DTM.NAMESPACE_NODE == type))
      {
        context = getParent(context);
        first = getFirstChild(context);

        if (NULL != first)
        {
          if (getExpandedTypeID(first) == expandedTypeID)
            return first;
          else
            return next(context, first, expandedTypeID);
        }
      }

      do
      {
        first = getNextSibling(context);

        if (NULL == first)
          context = getParent(context);
        else
        {
          if (getExpandedTypeID(first) == expandedTypeID)
            return first;
          else
            return next(context, first, expandedTypeID);
        }
      }
      while (NULL == first && NULL != context);

      return first;
    }

    /**
     * Traverse to the next node after the current node.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current)
    {
			// Compute in identity space
			current=makeNodeIdentity(current);

      while (true)
      {
        current++; // Only works on IDs, not handles.

				// %REVIEW% Are we using handles or indexes?
        int type = _type(current);  // may call nextNode()

        if (NULL == type)
          return NULL;

        if (ATTRIBUTE_NODE == type || NAMESPACE_NODE == type)
          continue;

        return makeNodeHandle(current);  // make handle.
      }
    }

    /**
     * Traverse to the next node after the current node that is matched
     * by the expanded type ID.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     * @param expandedTypeID The expanded type ID that must match.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current, int expandedTypeID)
    {
			// Compute in ID space
			current=makeNodeIdentity(current);

      while (true)
      {
        current++;

        int etype = _exptype(current);  // may call nextNode()

        if (NULL == etype)
          return NULL;

        if (etype != expandedTypeID)
          continue;

        return makeNodeHandle(current);  // make handle.
      }
    }
  }

  /**
   * Implements traversal of the Ancestor access, in reverse document order.
   */
  private class FollowingSiblingTraverser extends DTMAxisTraverser
  {

    /**
     * Traverse to the next node after the current node.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current)
    {
      return getNextSibling(current);
    }

    /**
     * Traverse to the next node after the current node that is matched
     * by the expanded type ID.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     * @param expandedTypeID The expanded type ID that must match.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current, int expandedTypeID)
    {

      while (DTM.NULL != (current = getNextSibling(current)))
      {
        if (getExpandedTypeID(current) == expandedTypeID)
          return current;
      }

      return NULL;
    }
  }

  /**
   * Implements traversal of the Ancestor access, in reverse document order.
   */
  private class NamespaceDeclsTraverser extends DTMAxisTraverser
  {

    /**
     * Traverse to the next node after the current node.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current)
    {

      return (context == current)
             ? getFirstNamespaceNode(context, false)
             : getNextNamespaceNode(context, current, false);
    }

    /**
     * Traverse to the next node after the current node that is matched
     * by the expanded type ID.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     * @param expandedTypeID The expanded type ID that must match.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current, int expandedTypeID)
    {

      current = (context == current)
                ? getFirstNamespaceNode(context, false)
                : getNextNamespaceNode(context, current, false);

      do
      {
        if (getExpandedTypeID(current) == expandedTypeID)
          return current;
      }
      while (DTM.NULL
             != (current = getNextNamespaceNode(context, current, false)));

      return NULL;
    }
  }

  /**
   * Implements traversal of the Ancestor access, in reverse document order.
   */
  private class NamespaceTraverser extends DTMAxisTraverser
  {

    /**
     * Traverse to the next node after the current node.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current)
    {

      return (context == current)
             ? getFirstNamespaceNode(context, true)
             : getNextNamespaceNode(context, current, true);
    }

    /**
     * Traverse to the next node after the current node that is matched
     * by the expanded type ID.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     * @param expandedTypeID The expanded type ID that must match.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current, int expandedTypeID)
    {

      current = (context == current)
                ? getFirstNamespaceNode(context, true)
                : getNextNamespaceNode(context, current, true);

      do
      {
        if (getExpandedTypeID(current) == expandedTypeID)
          return current;
      }
      while (DTM.NULL
             != (current = getNextNamespaceNode(context, current, true)));

      return NULL;
    }
  }

  /**
   * Implements traversal of the Ancestor access, in reverse document order.
   */
  private class ParentTraverser extends DTMAxisTraverser
  {
    /**
     * By the nature of the stateless traversal, the context node can not be
     * returned or the iteration will go into an infinate loop.  So to traverse 
     * an axis, the first function must be used to get the first node.
     *
     * <p>This method needs to be overloaded only by those axis that process
     * the self node. <\p>
     *
     * @param context The context node of this traversal. This is the point
     * that the traversal starts from.
     * @return the first node in the traversal.
     */
    public int first(int context)
    {
      return getParent(context);
    }
  
    /**
     * By the nature of the stateless traversal, the context node can not be
     * returned or the iteration will go into an infinate loop.  So to traverse 
     * an axis, the first function must be used to get the first node.
     *
     * <p>This method needs to be overloaded only by those axis that process
     * the self node. <\p>
     *
     * @param context The context node of this traversal. This is the point
     * of origin for the traversal -- its "root node" or starting point.
     * @param expandedTypeID The expanded type ID that must match.
     *
     * @return the first node in the traversal.
     */
    public int first(int current, int expandedTypeID)
    {
			// Compute in ID space
      current = makeNodeIdentity(current);

      while (NULL != (current = m_parent.elementAt(current)))
      {
        if (m_exptype.elementAt(current) == expandedTypeID)
          return makeNodeHandle(current);
      }

      return NULL;
    }


    /**
     * Traverse to the next node after the current node.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current)
    {

      return NULL;
    }
    


    /**
     * Traverse to the next node after the current node that is matched
     * by the expanded type ID.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     * @param expandedTypeID The expanded type ID that must match.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current, int expandedTypeID)
    {

      return NULL;
    }
  }

  /**
   * Implements traversal of the Ancestor access, in reverse document order.
   */
  private class PrecedingTraverser extends DTMAxisTraverser
  {

    /**
     * Tell if the current identity is an ancestor of the context identity.
     * This is an expensive operation, made worse by the stateless traversal.
     * But the preceding axis is used fairly infrequently.
     *
     * @param contextIdent The context node of the axis traversal.
     * @param currentIdent The node in question.
     * @return true if the currentIdent node is an ancestor of contextIdent.
     */
    protected boolean isAncestor(int contextIdent, int currentIdent)
    {
			// %REVIEW% See comments in IsAfterAxis; using the "successor" of
			// contextIdent is probably more efficient.
      for (contextIdent = m_parent.elementAt(contextIdent); DTM.NULL != contextIdent;
              contextIdent = m_parent.elementAt(contextIdent))
      {
        if (contextIdent == currentIdent)
          return true;
      }

      return false;
    }

    /**
     * Traverse to the next node after the current node.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current)
    {
			// compute in ID space
      int subtreeRootIdent = makeNodeIdentity(context);

      for (current = makeNodeIdentity(current) - 1; current >= 0; current--)
      {
        short type = _type(current);

        if (ATTRIBUTE_NODE == type || NAMESPACE_NODE == type
                || isAncestor(subtreeRootIdent, current))
          continue;

        return makeNodeHandle(current);  // make handle.
      }

      return NULL;
    }

    /**
     * Traverse to the next node after the current node that is matched
     * by the expanded type ID.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     * @param expandedTypeID The expanded type ID that must match.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current, int expandedTypeID)
    {
			// Compute in ID space
      int subtreeRootIdent = makeNodeIdentity(context);

      for (current = makeNodeIdentity(current) - 1; current >= 0; current--)
      {
        int exptype = m_exptype.elementAt(current);

        if (exptype != expandedTypeID
                || isAncestor(subtreeRootIdent, current))
          continue;

        return makeNodeHandle(current);  // make handle.
      }

      return NULL;
    }
  }

  /**
   * Implements traversal of the Ancestor and the Preceding axis,
   * in reverse document order.
   */
  private class PrecedingAndAncestorTraverser extends DTMAxisTraverser
  {

    /**
     * Traverse to the next node after the current node.
     *
     * @param context The context node of this iteration.
     * @param current The current node of the iteration.
     *
     * @return the next node in the iteration, or DTM.NULL.
     */
    public int next(int context, int current)