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.xalan.xsltc.dom;
  
  import org.apache.xalan.xsltc.NodeIterator;
  import org.apache.xalan.xsltc.runtime.BasisLibrary;
  
  /**
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   * @author Morten Jorgensen
   */
  public abstract class NodeIteratorBase implements NodeIterator {
  
      /**
       * Cached computed value of last().
       */
      protected int _last = -1;
  
      /**
       * Value of position() in this iterator. Incremented in
       * returnNode().
       */
      protected int _position = 0;
  
      /**
       * Store node in call to setMark().
       */
      protected int _markedNode;
  
      /**
       * Store node in call to setStartNode().
       */
      protected int _startNode = NodeIterator.END;
  
      /** 
       * Flag indicating if "self" should be returned.
       */
      protected boolean _includeSelf = false;
  
      /**
       * Flag indicating if iterator can be restarted.
       */
      protected boolean _isRestartable = true;
  
      /**
       * Setter for _isRestartable flag. 
       */
      public void setRestartable(boolean isRestartable) {
  	_isRestartable = isRestartable;
      }
  
      /**
       * Initialize iterator using a node. If iterator is not
       * restartable, then do nothing. If node is equal to END then
       * subsequent calls to next() must return END.
       */
      abstract public NodeIterator setStartNode(int node);
  
      /**
       * Reset this iterator using state from last call to
       * setStartNode().
       */
      public NodeIterator reset() {
  	final boolean temp = _isRestartable;
  	_isRestartable = true;
  	// Must adjust _startNode if self is included
  	setStartNode(_includeSelf ? _startNode + 1 : _startNode);
  	_isRestartable = temp;
  	return this;
      }
  
      /**
       * Setter for _includeSelf flag.
       */
      public NodeIterator includeSelf() {
  	_includeSelf = true;
  	return this;
      }
  
      /**
       * Default implementation of getLast(). Stores current position
       * and current node, resets the iterator, counts all nodes and
       * restores iterator to original state.
       */
      public int getLast() {
  	if (_last == -1) {
  	    final int temp = _position;
  	    setMark();
  	    reset();
  	    do {
  		_last++;
  	    } while (next() != END);
  	    gotoMark();
  	    _position = temp;
  	}
  	return _last;
      }
  
      /**
       * Returns the position() in this iterator.
       */
      public int getPosition() {
  	return _position == 0 ? 1 : _position;
      }
  
      /**
       * Indicates if position in this iterator is computed in reverse
       * document order. Note that nodes are always returned in document
       * order.
       */
      public boolean isReverse() {
  	return false;
      }
      
      /**
       * Clones and resets this iterator. Note that the cloned iterator is 
       * not restartable. This is because cloning is needed for variable 
       * references, and the context node of the original variable 
       * declaration must be preserved.
       */
      public NodeIterator cloneIterator() {
  	try {
  	    final NodeIteratorBase clone = (NodeIteratorBase)super.clone();
  	    clone._isRestartable = false;
  	    return clone.reset();
  	}
  	catch (CloneNotSupportedException e) {
  	    BasisLibrary.runTimeError(BasisLibrary.ITERATOR_CLONE_ERR,
  				      e.toString());
  	    return null;
  	}
      }
      
      /**
       * Utility method that increments position and returns its
       * argument.
       */
      protected final int returnNode(final int node) {
  	_position++;
  	return node;
      }
      
      /**
       * Reset the position in this iterator.
       */
      protected final NodeIterator resetPosition() {
  	_position = 0;
  	return this;
      }
  }
  