1 /*
2  * $Header: /cvsroot/jaxen/jaxen/src/java/main/org/jaxen/expr/DefaultRelationalExpr.java,v 1.8 2002/04/26 17:17:34 jstrachan Exp $
3  * $Revision: 1.8 $
4  * $Date: 2002/04/26 17:17:34 $
5  *
6  * ====================================================================
7  *
8  * Copyright (C) 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
13  * are met:
14  *
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions, and the following disclaimer.
17  *
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions, and the disclaimer that follows
20  *    these conditions in the documentation and/or other materials
21  *    provided with the distribution.
22  *
23  * 3. The name "Jaxen" must not be used to endorse or promote products
24  *    derived from this software without prior written permission.  For
25  *    written permission, please contact license@jaxen.org.
26  *
27  * 4. Products derived from this software may not be called "Jaxen", nor
28  *    may "Jaxen" appear in their name, without prior written permission
29  *    from the Jaxen Project Management (pm@jaxen.org).
30  *
31  * In addition, we request (but do not require) that you include in the
32  * end-user documentation provided with the redistribution and/or in the
33  * software itself an acknowledgement equivalent to the following:
34  *     "This product includes software developed by the
35  *      Jaxen Project (http://www.jaxen.org/)."
36  * Alternatively, the acknowledgment may be graphical using the logos
37  * available at http://www.jaxen.org/
38  *
39  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42  * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * ====================================================================
53  * This software consists of voluntary contributions made by many
54  * individuals on behalf of the Jaxen Project and was originally
55  * created by bob mcwhirter <bob@werken.com> and
56  * James Strachan <jstrachan@apache.org>.  For more information on the
57  * Jaxen Project, please see <http://www.jaxen.org/>.
58  *
59  * $Id: DefaultRelationalExpr.java,v 1.8 2002/04/26 17:17:34 jstrachan Exp $
60  */
61 
62 
63 
64 package org.jaxen.expr;
65 
66 import java.util.List;
67 import java.util.Iterator;
68 import org.jaxen.Context;
69 import org.jaxen.Navigator;
70 import org.jaxen.JaxenException;
71 import org.jaxen.function.NumberFunction;
72 
73 abstract class DefaultRelationalExpr extends DefaultTruthExpr
74   {
DefaultRelationalExpr( Expr lhs, Expr rhs )75   public DefaultRelationalExpr( Expr lhs, Expr rhs )
76     {
77     super( lhs, rhs );
78     }
79 
toString()80   public String toString()
81     {
82     return "[(DefaultRelationalExpr): " + getLHS() + ", " + getRHS() + "]";
83     }
84 
evaluate( Context context )85   public Object evaluate( Context context ) throws JaxenException
86     {
87     Object lhsValue = getLHS().evaluate( context );
88     Object rhsValue = getRHS().evaluate( context );
89     Navigator nav = context.getNavigator();
90 
91     if( bothAreSets( lhsValue, rhsValue ) )
92       {
93       return evaluateSetSet( (List) lhsValue, (List) rhsValue, nav );
94       }
95 
96     if( eitherIsSet( lhsValue, rhsValue ) )
97       {
98       if( isSet( lhsValue ) )
99         {
100         return evaluateSetSet( (List) lhsValue, convertToList( rhsValue ), nav );
101         }
102       else
103         {
104         return evaluateSetSet( convertToList( lhsValue ), (List) rhsValue, nav );
105         }
106       }
107 
108     return evaluateObjectObject( lhsValue, rhsValue, nav ) ? Boolean.TRUE : Boolean.FALSE;
109     }
110 
evaluateSetSet( List lhsSet, List rhsSet, Navigator nav )111   private Object evaluateSetSet( List lhsSet, List rhsSet, Navigator nav )
112     {
113     if( setIsEmpty( lhsSet ) || setIsEmpty( rhsSet ) ) // return false if either is null or empty
114       {
115       return Boolean.FALSE;
116       }
117 
118     for( Iterator lhsIterator = lhsSet.iterator(); lhsIterator.hasNext(); )
119       {
120       Object lhs = lhsIterator.next();
121 
122       for( Iterator rhsIterator = rhsSet.iterator(); rhsIterator.hasNext(); )
123         {
124         Object rhs = rhsIterator.next();
125 
126         if( evaluateObjectObject( lhs, rhs, nav ) )
127           {
128           return Boolean.TRUE;
129           }
130         }
131       }
132 
133     return Boolean.FALSE;
134     }
135 
evaluateObjectObject( Object lhs, Object rhs, Navigator nav )136   private boolean evaluateObjectObject( Object lhs, Object rhs, Navigator nav )
137     {
138     if( lhs == null || rhs == null )
139       {
140       return false;
141       }
142 
143     Double lhsNum = NumberFunction.evaluate( lhs, nav );
144     Double rhsNum = NumberFunction.evaluate( rhs, nav );
145 
146     if( NumberFunction.isNaN( lhsNum ) || NumberFunction.isNaN( rhsNum ) )
147       {
148       return false;
149       }
150 
151     return evaluateDoubleDouble( lhsNum, rhsNum );
152     }
153 
evaluateDoubleDouble( Double lhs, Double rhs )154   protected abstract boolean evaluateDoubleDouble( Double lhs, Double rhs );
155   }
156 
157