PrecedingEnumeration.java

package org.cdlib.xtf.lazyTree;

import net.sf.saxon.om.SequenceIterator;
import net.sf.saxon.pattern.NodeTest;

final class PrecedingEnumeration extends TreeEnumeration 
{
  NodeImpl nextAncestor;

  public PrecedingEnumeration(NodeImpl node, NodeTest nodeTest) 
  {
    super(node, nodeTest);

    // we need to avoid returning ancestors of the starting node
    nextAncestor = (NodeImpl)node.getParent();
    advance();
  }

  /**
  * Special code to skip the ancestors of the start node
  */
  protected boolean conforms(NodeImpl node) 
  {
    // ASSERT: we'll never test the root node, because it's always
    // an ancestor, so nextAncestor will never be null.
    if (node != null) 
    {
      if (node.isSameNodeInfo(nextAncestor)) {
        nextAncestor = (NodeImpl)nextAncestor.getParent();
        return false;
      }
    }
    return super.conforms(node);
  }

  protected void step() {
    next = next.getPreviousInDocument();
  }
  
  /**
  * Get another enumeration of the same nodes
  */
  public SequenceIterator getAnother() {
    return new PrecedingEnumeration(start, nodeTest);
  }
}

//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (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.mozilla.org/MPL/ 
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License. 
//
// The Original Code is: all this file. 
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved. 
//
// Contributor(s): none. 
//