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;
  
  /**
   * This iterator is a wrapper that always returns the position of
   * a node in document order. It is needed for the case where 
   * a call to position() occurs in the context of an XSLT element
   * such as xsl:for-each, xsl:apply-templates, etc. 
   *
   * The getPosition() methods in DTMAxisIterators defined
   * in DTMDefaultBaseIterators always return the position
   * in document order, which is backwards for XPath in the
   * case of the ancestor, ancestor-or-self, previous and
   * previous-sibling.
   *
   * XSLTC implements position() with the
   * BasisLibrary.positionF() method, and uses the
   * DTMAxisIterator.isReverse() method to determine
   * whether the result of getPosition() should be
   * interpreted as being equal to position().
   * But when the expression appears in apply-templates of
   * for-each, the position() function operates in document
   * order.
   *
   * The only effect of the ForwardPositionIterator is to force
   * the result of isReverse() to false, so that
   * BasisLibrary.positionF() calculates position() in a way
   * that's consistent with the context in which the
   * iterator is being used."
   *
   * (Apparently the correction of isReverse() occurs
   * implicitly, by inheritance. This class also appears
   * to maintain its own position counter, which seems
   * redundant.)
   *
   * @deprecated This class exists only for backwards compatibility with old
   *             translets.  New code should not reference it.
   */
  public final class ForwardPositionIterator extends DTMAxisIteratorBase {
  
      private DTMAxisIterator _source;
  
      public ForwardPositionIterator(DTMAxisIterator source) {
  	_source = source;
      }
  
      public DTMAxisIterator cloneIterator() {
  	try {
  	    final ForwardPositionIterator clone = 
  		(ForwardPositionIterator) 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 int next() {
  	return returnNode(_source.next());
      }
  	
      public DTMAxisIterator setStartNode(int node) {
  	_source.setStartNode(node);
  	return this;
      }
  
      public DTMAxisIterator reset() {
  	_source.reset();
  	return resetPosition();
      }
  
      public void setMark() {
  	_source.setMark();
      }
  
      public void gotoMark() {
  	_source.gotoMark();
      }
  }
  