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1   /*
2    * $Header$
3    * $Revision: 1128 $
4    * $Date: 2006-02-05 13:49:04 -0800 (Sun, 05 Feb 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: DefaultRelationalExpr.java 1128 2006-02-05 21:49:04Z elharo $
46   */
47  
48  
49  
50  package org.jaxen.expr;
51  
52  import java.util.Iterator;
53  import java.util.List;
54  import org.jaxen.Context;
55  import org.jaxen.JaxenException;
56  import org.jaxen.Navigator;
57  import org.jaxen.function.NumberFunction;
58  
59  abstract class DefaultRelationalExpr extends DefaultTruthExpr implements RelationalExpr 
60    {
61    DefaultRelationalExpr( Expr lhs, Expr rhs )
62      {
63      super( lhs, rhs );
64      }
65    
66    public String toString()
67      {
68      return "[(DefaultRelationalExpr): " + getLHS() + ", " + getRHS() + "]";
69      }
70  
71    public Object evaluate( Context context ) throws JaxenException
72      {
73      Object lhsValue = getLHS().evaluate( context );
74      Object rhsValue = getRHS().evaluate( context );
75      Navigator nav = context.getNavigator();
76  
77      if( bothAreSets( lhsValue, rhsValue ) )
78        {
79        return evaluateSetSet( (List) lhsValue, (List) rhsValue, nav );
80        }
81  
82      if( eitherIsSet( lhsValue, rhsValue ) )
83        {
84        if( isSet( lhsValue ) )
85          {        
86          return evaluateSetSet( (List) lhsValue, convertToList( rhsValue ), nav );              
87          }
88        else
89          {
90          return evaluateSetSet( convertToList( lhsValue ), (List) rhsValue, nav );              
91          }
92        }
93      
94      return evaluateObjectObject( lhsValue, rhsValue, nav ) ? Boolean.TRUE : Boolean.FALSE;
95      }
96  
97    private Object evaluateSetSet( List lhsSet, List rhsSet, Navigator nav )
98      {
99      if( setIsEmpty( lhsSet ) || setIsEmpty( rhsSet ) ) // return false if either is null or empty
100       {
101       return Boolean.FALSE;
102       }    
103     
104     for( Iterator lhsIterator = lhsSet.iterator(); lhsIterator.hasNext(); )
105       {
106       Object lhs = lhsIterator.next();        
107       
108       for( Iterator rhsIterator = rhsSet.iterator(); rhsIterator.hasNext(); )
109         {
110         Object rhs = rhsIterator.next();
111         
112         if( evaluateObjectObject( lhs, rhs, nav ) )
113           {
114           return Boolean.TRUE;
115           }
116         }
117       }      
118     
119     return Boolean.FALSE;
120     }
121   
122   private boolean evaluateObjectObject( Object lhs, Object rhs, Navigator nav )
123     {
124     if( lhs == null || rhs == null )
125       {
126       return false;
127       }
128     
129     Double lhsNum = NumberFunction.evaluate( lhs, nav );
130     Double rhsNum = NumberFunction.evaluate( rhs, nav );      
131     
132     if( NumberFunction.isNaN( lhsNum ) || NumberFunction.isNaN( rhsNum ) )
133       {
134       return false;
135       }
136     
137     return evaluateDoubleDouble( lhsNum, rhsNum );
138     }
139   
140   protected abstract boolean evaluateDoubleDouble( Double lhs, Double rhs );    
141   }
142