dtmdefaultbaseiterators.java

来自「java jdk 1.4的源码」· Java 代码 · 共 1,931 行 · 第 1/4 页

    /**
     * Returns a deep copy of this iterator.  The cloned iterator is not reset.
     *
     * @return a deep copy of this iterator.
     */
    public DTMAxisIterator cloneIterator()
    {
      _isRestartable = false;  // must set to false for any clone

      try
      {
        final AncestorIterator clone = (AncestorIterator) super.clone();

        clone._startNode = _startNode;

        // return clone.reset();
        return clone;
      }
      catch (CloneNotSupportedException e)
      {
        throw new DTMException(XSLMessages.createMessage(XSLTErrorResources.ER_ITERATOR_CLONE_NOT_SUPPORTED, null)); //"Iterator clone not supported.");
      }
    }

    /**
     * Set start to END should 'close' the iterator,
     * i.e. subsequent call to next() should return END.
     *
     * @param node Sets the root of the iteration.
     *
     * @return A DTMAxisIterator set to the start of the iteration.
     */
    public DTMAxisIterator setStartNode(int node)
    {
      m_realStartNode = node;

      if (_isRestartable)
      {
        if (_includeSelf)
          _startNode = node;
        else
          _startNode = getParent(node);

        node = _startNode;
        while (node != END)
        {
          m_ancestors.addElement(node);
          node = getParent(node);
        }
        m_ancestorsPos = m_ancestors.size()-1;

        _currentNode = (m_ancestorsPos>=0)
                               ? m_ancestors.elementAt(m_ancestorsPos)
                               : DTM.NULL;

        return resetPosition();
      }

      return this;
    }

    /**
     * Resets the iterator to the last start node.
     *
     * @return A DTMAxisIterator, which may or may not be the same as this
     *         iterator.
     */
    public DTMAxisIterator reset()
    {

      m_ancestorsPos = m_ancestors.size()-1;

      _currentNode = (m_ancestorsPos>=0) ? m_ancestors.elementAt(m_ancestorsPos)
                                         : DTM.NULL;

      return resetPosition();
    }

    /**
     * Get the next node in the iteration.
     *
     * @return The next node handle in the iteration, or END.
     */
    public int next()
    {

      int next = _currentNode;
      
      int pos = --m_ancestorsPos;

      _currentNode = (pos >= 0) ? m_ancestors.elementAt(m_ancestorsPos)
                                : DTM.NULL;
      
      return returnNode(next);
    }
  }  // end of AncestorIterator

  /**
   * Typed iterator that returns the ancestors of a given node.
   */
  private final class TypedAncestorIterator extends AncestorIterator
  {

    /** The extended type ID that was requested. */
    private final int _nodeType;

    /**
     * Constructor TypedAncestorIterator
     *
     *
     * @param type The extended type ID being requested.
     */
    public TypedAncestorIterator(int type)
    {
      _nodeType = type;
    }

    /**
     * Get the next node in the iteration.
     *
     * @return The next node handle in the iteration, or END.
     */
    public int next()
    {

      int node;

      while ((node = super.next()) != NULL)
      {
        if (getExpandedTypeID(node) == _nodeType)
          return returnNode(node);
      }

      return (NULL);
    }

    /**
     * Returns the last element in this interation.
     *
     * @return the last element in this interation.
     */
    public int getLast()
    {

      int last = NULL;
      int curr = _startNode;

      while (curr != NULL)
      {
        if (getExpandedTypeID(curr) == _nodeType)
          last = curr;

        curr = getParent(curr);
      }

      return (last);
    }
  }  // end of TypedAncestorIterator

  /**
   * Iterator that returns the descendants of a given node.
   */
  private class DescendantIterator extends InternalAxisIteratorBase
  {

    /**
     * Set start to END should 'close' the iterator,
     * i.e. subsequent call to next() should return END.
     *
     * @param node Sets the root of the iteration.
     *
     * @return A DTMAxisIterator set to the start of the iteration.
     */
    public DTMAxisIterator setStartNode(int node)
    {

      if (_isRestartable)
      {
        node = makeNodeIdentity(node);
        _startNode = node;

        if (_includeSelf)
          node--;

        _currentNode = node;

        return resetPosition();
      }

      return this;
    }

    /**
     * Tell if this node identity is a descendant.  Assumes that
     * the node info for the element has already been obtained.
     *
     * This one-sided test works only if the parent has been
     * previously tested and is known to be a descendent. It fails if
     * the parent is the _startNode's next sibling, or indeed any node
     * that follows _startNode in document order.  That may suffice
     * for this iterator, but it's not really an isDescendent() test.
     * %REVIEW% rename?
     *
     * @param identity The index number of the node in question.
     * @return true if the index is a descendant of _startNode.
     */
    protected boolean isDescendant(int identity)
    {
      return (_startNode == identity) || _parent(identity) >= _startNode;
    }

    /**
     * Get the next node in the iteration.
     *
     * @return The next node handle in the iteration, or END.
     */
    public int next()
    {

      while (true)
      {
        int node = ++_currentNode;
        int type = _type(node);

        if (NULL == type ||!isDescendant(node))
          return END;

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

        return returnNode(makeNodeHandle(node));  // make handle.
      }
    }
  }  // end of DescendantIterator

  /**
   * Typed iterator that returns the descendants of a given node.
   */
  private final class TypedDescendantIterator extends DescendantIterator
  {

    /** The extended type ID that was requested. */
    private final int _nodeType;

    /**
     * Constructor TypedDescendantIterator
     *
     *
     * @param nodeType Extended type ID being requested.
     */
    public TypedDescendantIterator(int nodeType)
    {
      _nodeType = nodeType;
    }

    /**
     * Get the next node in the iteration.
     *
     * @return The next node handle in the iteration, or END.
     */
    public int next()
    {

      int node;

      while ((node = super.next()) != NULL
             && getExpandedTypeID(node) != _nodeType){}

      return node;
    }
  }  // end of TypedDescendantIterator

  /**
   * Iterator that returns the descendants of a given node.
   * I'm not exactly clear about this one... -sb
   */
  private class NthDescendantIterator extends DescendantIterator
  {

    /** The current nth position. */
    int _pos;

    /**
     * Constructor NthDescendantIterator
     *
     *
     * @param pos The nth position being requested.
     */
    public NthDescendantIterator(int pos)
    {
      _pos = pos;
    }

    /**
     * Get the next node in the iteration.
     *
     * @return The next node handle in the iteration, or END.
     */
    public int next()
    {

      // I'm not exactly clear yet what this is doing... -sb
      int node;

      while ((node = super.next()) != END)
      {
        node = makeNodeIdentity(node);

        int parent = _parent(node);
        int child = _firstch(parent);
        int pos = 0;

        do
        {
          int type = _type(child);

          if (ELEMENT_NODE == type)
            pos++;
        }
        while ((pos < _pos) && (child = _nextsib(child)) != END);

        if (node == child)
          return node;
      }

      return (END);
    }
  }  // end of NthDescendantIterator

  /**
   * Class SingletonIterator.
   */
  private class SingletonIterator extends InternalAxisIteratorBase
  {

    /** (not sure yet what this is.  -sb)  (sc & sb remove final to compile in JDK 1.1.8) */
    private boolean _isConstant;

    /**
     * Constructor SingletonIterator
     *
     */
    public SingletonIterator()
    {
      this(Integer.MIN_VALUE, false);
    }

    /**
     * Constructor SingletonIterator
     *
     *
     * @param node The node handle to return.
     */
    public SingletonIterator(int node)
    {
      this(node, false);
    }

    /**
     * Constructor SingletonIterator
     *
     *
     * @param node the node handle to return.
     * @param constant (Not sure what this is yet.  -sb)
     */
    public SingletonIterator(int node, boolean constant)
    {
      _currentNode = _startNode = node;
      _isConstant = constant;
    }

    /**
     * Set start to END should 'close' the iterator,
     * i.e. subsequent call to next() should return END.
     *
     * @param node Sets the root of the iteration.
     *
     * @return A DTMAxisIterator set to the start of the iteration.
     */
    public DTMAxisIterator setStartNode(int node)
    {

      if (_isConstant)
      {
        _currentNode = _startNode;

        return resetPosition();
      }
      else if (_isRestartable)
      {
        if (_currentNode == Integer.MIN_VALUE)
        {
          _currentNode = _startNode = node;
        }

        return resetPosition();
      }

      return this;
    }

    /**
     * Resets the iterator to the last start node.
     *
     * @return A DTMAxisIterator, which may or may not be the same as this
     *         iterator.
     */
    public DTMAxisIterator reset()
    {

      if (_isConstant)
      {
        _currentNode = _startNode;

        return resetPosition();
      }
      else
      {
        final boolean temp = _isRestartable;

        _isRestartable = true;

        setStartNode(_startNode);

        _isRestartable = temp;
      }

      return this;
    }

    /**
     * Get the next node in the iteration.
     *
     * @return The next node handle in the iteration, or END.
     */
    public int next()
    {

      final int result = _currentNode;

      _currentNode = END;

      return returnNode(result);
    }
  }

  /**
   * Iterator that returns a given node only if it is of a given type.
   */
  private final class TypedSingletonIterator extends SingletonIterator
  {

    /** The extended type ID that was requested. */
    private final int _nodeType;

    /**
     * Constructor TypedSingletonIterator
     *
     *
     * @param nodeType The extended type ID being requested.
     */
    public TypedSingletonIterator(int nodeType)
    {
      _nodeType = nodeType;
    }

    /**
     * Get the next node in the iteration.
     *
     * @return The next node handle in the iteration, or END.
     */
    public int next()
    {

      final int result = super.next();

      return getExpandedTypeID(result) == _nodeType ? result : NULL;
    }
  }  // end of TypedSingletonIterator
}