content: /*
   * $Header$
   * $Revision$
   * $Date$
   *
   * ====================================================================
   *
   * Copyright 2000-2002 bob mcwhirter & James Strachan.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   * 
   *   * Redistributions of source code must retain the above copyright
   *     notice, this list of conditions and the following disclaimer.
   * 
   *   * Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution.
   * 
   *   * Neither the name of the Jaxen Project nor the names of its
   *     contributors may be used to endorse or promote products derived 
   *     from this software without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
   * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * ====================================================================
   * This software consists of voluntary contributions made by many 
   * individuals on behalf of the Jaxen Project and was originally 
   * created by bob mcwhirter <bob@werken.com> and 
   * James Strachan <jstrachan@apache.org>.  For more information on the 
   * Jaxen Project, please see <http://www.jaxen.org/>.
   * 
   * $Id$
   */
  
  
  
  package org.jaxen.expr;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Set;
  import org.jaxen.Context;
  import org.jaxen.JaxenException;
  import org.jaxen.XPathSyntaxException;
  
  /**
   * @deprecated this class will become non-public in the future;
   *     use the interface instead
   */
  public class DefaultUnionExpr extends DefaultBinaryExpr implements UnionExpr
  {
      /**
       * 
       */
      private static final long serialVersionUID = 7629142718276852707L;
  
      public DefaultUnionExpr(Expr lhs,
                              Expr rhs)
      {
          super( lhs,
                 rhs );
      }
  
      public String getOperator()
      {
          return "|";
      }
  
      public String toString()
      {
          return "[(DefaultUnionExpr): " + getLHS() + ", " + getRHS() + "]";
      }
  
      public Object evaluate(Context context) throws JaxenException
      {
          List results = new ArrayList();
  
          try {
              List lhsResults = (List) getLHS().evaluate( context );
              List rhsResults = (List) getRHS().evaluate( context );
      
              Set unique = new HashSet();
      
              results.addAll( lhsResults );
              unique.addAll( lhsResults );
      
              Iterator rhsIter = rhsResults.iterator();
      
              while ( rhsIter.hasNext() )
              {
                  Object each = rhsIter.next();
      
                  if ( ! unique.contains( each ) )
                  {
                      results.add( each );
                      unique.add( each );
                  }
              }
              
              Collections.sort(results, new NodeComparator(context.getNavigator()));
      
              return results;
          }
          catch (ClassCastException e) {
              throw new XPathSyntaxException(this.getText(), context.getPosition(), "Unions are only allowed over node-sets");
          }
      }
      
  }
  
  