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1   /*
2    * $Header$
3    * $Revision: 1261 $
4    * $Date: 2006-11-30 10:49:27 -0800 (Thu, 30 Nov 2006) $
5    *
6    * ====================================================================
7    *
8    * Copyright 2000-2002 bob mcwhirter & James Strachan.
9    * All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions are
13   * met:
14   * 
15   *   * Redistributions of source code must retain the above copyright
16   *     notice, this list of conditions and the following disclaimer.
17   * 
18   *   * Redistributions in binary form must reproduce the above copyright
19   *     notice, this list of conditions and the following disclaimer in the
20   *     documentation and/or other materials provided with the distribution.
21   * 
22   *   * Neither the name of the Jaxen Project nor the names of its
23   *     contributors may be used to endorse or promote products derived 
24   *     from this software without specific prior written permission.
25   * 
26   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27   * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
29   * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
30   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37   *
38   * ====================================================================
39   * This software consists of voluntary contributions made by many 
40   * individuals on behalf of the Jaxen Project and was originally 
41   * created by bob mcwhirter <bob@werken.com> and 
42   * James Strachan <jstrachan@apache.org>.  For more information on the 
43   * Jaxen Project, please see <http://www.jaxen.org/>.
44   * 
45   * $Id: DefaultUnionExpr.java 1261 2006-11-30 18:49:27Z elharo $
46   */
47  
48  
49  
50  package org.jaxen.expr;
51  
52  import java.util.ArrayList;
53  import java.util.Collections;
54  import java.util.HashSet;
55  import java.util.Iterator;
56  import java.util.List;
57  import java.util.Set;
58  import org.jaxen.Context;
59  import org.jaxen.JaxenException;
60  import org.jaxen.XPathSyntaxException;
61  
62  /**
63   * @deprecated this class will become non-public in the future;
64   *     use the interface instead
65   */
66  public class DefaultUnionExpr extends DefaultBinaryExpr implements UnionExpr
67  {
68      /**
69       * 
70       */
71      private static final long serialVersionUID = 7629142718276852707L;
72  
73      public DefaultUnionExpr(Expr lhs,
74                              Expr rhs)
75      {
76          super( lhs,
77                 rhs );
78      }
79  
80      public String getOperator()
81      {
82          return "|";
83      }
84  
85      public String toString()
86      {
87          return "[(DefaultUnionExpr): " + getLHS() + ", " + getRHS() + "]";
88      }
89  
90      public Object evaluate(Context context) throws JaxenException
91      {
92          List results = new ArrayList();
93  
94          try {
95              List lhsResults = (List) getLHS().evaluate( context );
96              List rhsResults = (List) getRHS().evaluate( context );
97      
98              Set unique = new HashSet();
99      
100             results.addAll( lhsResults );
101             unique.addAll( lhsResults );
102     
103             Iterator rhsIter = rhsResults.iterator();
104     
105             while ( rhsIter.hasNext() )
106             {
107                 Object each = rhsIter.next();
108     
109                 if ( ! unique.contains( each ) )
110                 {
111                     results.add( each );
112                     unique.add( each );
113                 }
114             }
115             
116             Collections.sort(results, new NodeComparator(context.getNavigator()));
117     
118             return results;
119         }
120         catch (ClassCastException e) {
121             throw new XPathSyntaxException(this.getText(), context.getPosition(), "Unions are only allowed over node-sets");
122         }
123     }
124     
125 }
126