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.runtime.BasisLibrary;
  import org.apache.xml.dtm.DTMAxisIterator;
  import org.apache.xml.dtm.ref.DTMAxisIteratorBase;
  
  /**
   * @author Jacek Ambroziak
   * @author Morten Jorgensen
   */
  public final class NthIterator extends DTMAxisIteratorBase {
      // ...[N]
      private DTMAxisIterator _source;
      private final int _position;
      private boolean _ready;
  
      public NthIterator(DTMAxisIterator source, int n) {
  	_source = source;
  	_position = n;
      }
  
      public void setRestartable(boolean isRestartable) {
  	_isRestartable = isRestartable;
  	_source.setRestartable(isRestartable);
      }
      
      public DTMAxisIterator cloneIterator() {
  	try {
  	    final NthIterator clone = (NthIterator) super.clone();
  	    clone._source = _source.cloneIterator();	// resets source
  	    clone._isRestartable = false;
  	    return clone;
  	}
  	catch (CloneNotSupportedException e) {
  	    BasisLibrary.runTimeError(BasisLibrary.ITERATOR_CLONE_ERR,
  				      e.toString());
  	    return null;
  	}
      }
  
      public int next() {
  	if (_ready) {
  	    _ready = false;
  	    return _source.getNodeByPosition(_position);
  	}
  	return DTMAxisIterator.END;
  	/*
  	if (_ready && _position > 0) {
              final int pos = _source.isReverse()
                                         ? _source.getLast() - _position + 1
                                         : _position;
  
  	    _ready = false;
  	    int node;
  	    while ((node = _source.next()) != DTMAxisIterator.END) {
  		if (pos == _source.getPosition()) {
  		    return node;
  		}
  	    }
  	}
  	return DTMAxisIterator.END;
  	*/
      }
  
      public DTMAxisIterator setStartNode(final int node) {
  	if (_isRestartable) {
  	    _source.setStartNode(node);
  	    _ready = true;
  	}
  	return this;
      }
  	
      public DTMAxisIterator reset() {
  	_source.reset();
  	_ready = true;
  	return this;
      }
      
      public int getLast() {
  	return 1;
      }
      
      public int getPosition() {
  	return 1;
      }
      
      public void setMark() {
  	_source.setMark();
      }
      
      public void gotoMark() {
  	_source.gotoMark();
      }
  }
  