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.DTMFilter;
  import org.apache.xml.dtm.DTMIterator;
  import org.apache.xml.dtm.ref.DTMAxisIteratorBase;
  
  /**
   * Similar to a CurrentNodeListIterator except that the filter has a 
   * simpler interface (only needs the node, no position, last, etc.)  
   * It takes a source iterator and a Filter object and returns nodes 
   * from the source after filtering them by calling filter.test(node).
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   */
  public final class FilterIterator extends DTMAxisIteratorBase {
  
      /**
       * Reference to source iterator.
       */
      private DTMAxisIterator _source;
  
      /**
       * Reference to a filter object that to be applied to each node.
       */
      private final DTMFilter _filter;
  
      /**
       * A flag indicating if position is reversed.
       */
      private final boolean _isReverse;
  	
      public FilterIterator(DTMAxisIterator source, DTMFilter filter) {
  	_source = source;
  // System.out.println("FI souce = " + source + " this = " + this);
  	_filter = filter;
  	_isReverse = source.isReverse();
      }
  
      public boolean isReverse() {
  	return _isReverse;
      }
  
  
      public void setRestartable(boolean isRestartable) {
  	_isRestartable = isRestartable;
  	_source.setRestartable(isRestartable);
      }
  
      public DTMAxisIterator cloneIterator() {
  
  	try {
  	    final FilterIterator clone = (FilterIterator) super.clone();
  	    clone._source = _source.cloneIterator();
  	    clone._isRestartable = false;
  	    return clone.reset();
  	}
  	catch (CloneNotSupportedException e) {
  	    BasisLibrary.runTimeError(BasisLibrary.ITERATOR_CLONE_ERR,
  				      e.toString());
  	    return null;
  	}
      }
      
      public DTMAxisIterator reset() {
  	_source.reset();
  	return resetPosition();
      }
      
      public int next() {
  	int node;
  	while ((node = _source.next()) != END) {
  	    if (_filter.acceptNode(node, DTMFilter.SHOW_ALL) == DTMIterator.FILTER_ACCEPT) {
  		return returnNode(node);
  	    }
  	}
  	return END;
      }
  
      public DTMAxisIterator setStartNode(int node) {
  	if (_isRestartable) {
  	    _source.setStartNode(_startNode = node); 
  	    return resetPosition();
  	}
  	return this;
      }
  
      public void setMark() {
  	_source.setMark();
      }
  
      public void gotoMark() {
  	_source.gotoMark();
      }
  
  }
  