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Java > Open Source Codes > org > jaxen > expr > DefaultEqualityExpr


1 /*
2  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultEqualityExpr.java,v 1.12 2005/05/16 10:46:43 elharo Exp $
3  * $Revision: 1.12 $
4  * $Date: 2005/05/16 10:46:43 $
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: DefaultEqualityExpr.java,v 1.12 2005/05/16 10:46:43 elharo Exp $
60  */

61
62
63
64 package org.jaxen.expr;
65
66 import java.util.Iterator JavaDoc;
67 import java.util.List JavaDoc;
68 import org.jaxen.Context;
69 import org.jaxen.JaxenException;
70 import org.jaxen.Navigator;
71 import org.jaxen.function.BooleanFunction;
72 import org.jaxen.function.NumberFunction;
73 import org.jaxen.function.StringFunction;
74
75 abstract class DefaultEqualityExpr extends DefaultTruthExpr implements EqualityExpr
76   {
77   DefaultEqualityExpr( Expr lhs, Expr rhs )
78     {
79     super( lhs, rhs );
80     }
81
82   public String JavaDoc toString()
83     {
84     return "[(DefaultEqualityExpr): " + getLHS() + ", " + getRHS() + "]";
85     }
86   
87   public Object JavaDoc evaluate( Context context ) throws JaxenException
88     {
89     Object JavaDoc lhsValue = getLHS().evaluate( context );
90     Object JavaDoc rhsValue = getRHS().evaluate( context );
91     
92     if( lhsValue == null || rhsValue == null )
93       {
94       return Boolean.FALSE;
95       }
96     
97     Navigator nav = context.getNavigator();
98
99     if( bothAreSets( lhsValue, rhsValue ) )
100       {
101       return evaluateSetSet( (List JavaDoc) lhsValue, (List JavaDoc) rhsValue, nav );
102       }
103     else if ( eitherIsSet( lhsValue, rhsValue ) )
104       {
105       if ( isSet( lhsValue ) )
106         {
107         return evaluateSetSet( (List JavaDoc) lhsValue, convertToList( rhsValue ), nav );
108         }
109       else
110         {
111         return evaluateSetSet( convertToList( lhsValue ), (List JavaDoc) rhsValue, nav );
112         }
113       }
114     else
115       {
116       return evaluateObjectObject( lhsValue, rhsValue, nav ) ? Boolean.TRUE : Boolean.FALSE;
117       }
118     }
119   
120   private Boolean JavaDoc evaluateSetSet( List JavaDoc lhsSet, List JavaDoc rhsSet, Navigator nav )
121     {
122     if( setIsEmpty( lhsSet ) || setIsEmpty( rhsSet ) )
123       {
124       return Boolean.FALSE;
125       }
126     
127     for( Iterator JavaDoc lhsIterator = lhsSet.iterator(); lhsIterator.hasNext(); )
128       {
129       Object JavaDoc lhs = lhsIterator.next();
130       
131       for( Iterator JavaDoc rhsIterator = rhsSet.iterator(); rhsIterator.hasNext(); )
132         {
133         Object JavaDoc rhs = rhsIterator.next();
134         
135         if( evaluateObjectObject( lhs, rhs, nav ) )
136           {
137           return Boolean.TRUE;
138           }
139         }
140       }
141     
142     return Boolean.FALSE;
143     }
144   
145   private boolean evaluateObjectObject( Object JavaDoc lhs, Object JavaDoc rhs, Navigator nav )
146     {
147     if( eitherIsBoolean( lhs, rhs ) )
148       {
149       return evaluateObjectObject( BooleanFunction.evaluate( lhs, nav ),
150                                    BooleanFunction.evaluate( rhs, nav ) );
151       }
152     else if( eitherIsNumber( lhs, rhs ) )
153       {
154       return evaluateObjectObject( NumberFunction.evaluate( lhs,
155                                                             nav ),
156                                    NumberFunction.evaluate( rhs,
157                                                             nav ) );
158       }
159     else
160       {
161       return evaluateObjectObject( StringFunction.evaluate( lhs,
162                                                             nav ),
163                                    StringFunction.evaluate( rhs,
164                                                             nav ) );
165       }
166     }
167   
168   protected abstract boolean evaluateObjectObject( Object JavaDoc lhs, Object JavaDoc rhs );
169   }
170
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