1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultRelationalExpr.java,v 1.14 2006/02/05 21:47:40 elharo Exp $
3 * $Revision: 1.14 $
4 * $Date: 2006/02/05 21:47:40 $
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,v 1.14 2006/02/05 21:47:40 elharo Exp $
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