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.xalan.xsltc.util.IntegerArray;
  import org.apache.xml.dtm.DTMAxisIterator;
  import org.apache.xml.dtm.ref.DTMAxisIteratorBase;
  import org.apache.xml.dtm.ref.DTMDefaultBase;
  
  /**
   * Removes duplicates and sorts a source iterator. The nodes from the 
   * source are collected in an array upon calling setStartNode(). This
   * array is later sorted and duplicates are ignored in next().
   * @author G. Todd Miller 
   */
  public final class DupFilterIterator extends DTMAxisIteratorBase {
  
      /**
       * Reference to source iterator.
       */
      private DTMAxisIterator _source;
  
      /**
       * Array to cache all nodes from source.
       */
      private IntegerArray _nodes = new IntegerArray();
  
      /**
       * Index in _nodes array to current node.
       */
      private int _current = 0;
  
      /**
       * Cardinality of _nodes array.
       */
      private int _nodesSize = 0; 
  
      /**
       * Last value returned by next().
       */
      private int _lastNext = END;
  
      /**
       * Temporary variable to store _lastNext.
       */
      private int _markedLastNext = END;
  
      public DupFilterIterator(DTMAxisIterator source) {
  	_source = source;
  // System.out.println("DFI source = " + source + " this = " + this);
  
  	// Cache contents of id() or key() index right away. Necessary for
  	// union expressions containing multiple calls to the same index, and
  	// correct as well since start-node is irrelevant for id()/key() exrp.
  	if (source instanceof KeyIndex) {
  	    setStartNode(DTMDefaultBase.ROOTNODE);
  	}
      }
      
      /**
       * Set the start node for this iterator
       * @param node The start node
       * @return A reference to this node iterator
       */
      public DTMAxisIterator setStartNode(int node) {
  	if (_isRestartable) {
  	    // KeyIndex iterators are always relative to the root node, so there
  	    // is never any point in re-reading the iterator (and we SHOULD NOT).
              boolean sourceIsKeyIndex = _source instanceof KeyIndex;
  
  	    if (sourceIsKeyIndex
                      && _startNode == DTMDefaultBase.ROOTNODE) {
  		return this;
  	    }
  
  	    if (node != _startNode) {
  		_source.setStartNode(_startNode = node);
  
  		_nodes.clear();
  		while ((node = _source.next()) != END) {
  		    _nodes.add(node);
  		}
  
                  // Nodes produced by KeyIndex are known to be in document order.
                  // Take advantage of it.
                  if (!sourceIsKeyIndex) {
                      _nodes.sort();
                  }
  
  		_nodesSize = _nodes.cardinality();
  		_current = 0;
  		_lastNext = END;
  		resetPosition();
  	    }
  	}
  	return this;
      }
  
      public int next() {
  	while (_current < _nodesSize) {
  	    final int next = _nodes.at(_current++);
  	    if (next != _lastNext) {
  		return returnNode(_lastNext = next);
  	    }
  	}
  	return END;
      }
  
      public DTMAxisIterator cloneIterator() {
  	try {
  	    final DupFilterIterator clone =
  		(DupFilterIterator) super.clone();
  	    clone._nodes = (IntegerArray) _nodes.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 void setRestartable(boolean isRestartable) {
  	_isRestartable = isRestartable;
  	_source.setRestartable(isRestartable);
      }
     
      public void setMark() {
  	_markedNode = _current;
          _markedLastNext = _lastNext;    // Bugzilla 25924
      }
  
      public void gotoMark() {
  	_current = _markedNode;
          _lastNext = _markedLastNext;    // Bugzilla 25924
      }
  
      public DTMAxisIterator reset() {
  	_current = 0;
  	_lastNext = END;
  	return resetPosition();
      }
  }
  