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Java > Open Source Codes > org > objectstyle > cayenne > exp > parser > ASTEqual


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56 package org.objectstyle.cayenne.exp.parser;
57
58 import java.math.BigDecimal JavaDoc;
59
60 import org.objectstyle.cayenne.exp.Expression;
61
62 /**
63  * "Equal To" expression.
64  *
65  * @since 1.1
66  * @author Andrei Adamchik
67  */
68 public class ASTEqual extends ConditionNode {
69     /**
70      * Constructor used by expression parser. Do not invoke directly.
71      */
72     ASTEqual(int id) {
73         super(id);
74     }
75
76     public ASTEqual() {
77         super(ExpressionParserTreeConstants.JJTEQUAL);
78     }
79
80     /**
81      * Creates "Equal To" expression.
82      */
83     public ASTEqual(ASTPath path, Object JavaDoc value) {
84         super(ExpressionParserTreeConstants.JJTEQUAL);
85         jjtAddChild(path, 0);
86         jjtAddChild(new ASTScalar(value), 1);
87     }
88
89     protected Object JavaDoc evaluateNode(Object JavaDoc o) throws Exception JavaDoc {
90         int len = jjtGetNumChildren();
91         if (len != 2) {
92             return Boolean.FALSE;
93         }
94
95         Object JavaDoc o1 = evaluateChild(0, o);
96         Object JavaDoc o2 = evaluateChild(1, o);
97
98         // TODO: maybe we need a comparison "strategy" here, instead of
99 // a switch of all possible cases? ... there were other requests for
100 // more relaxed type-unsafe comparison (e.g. numbers to strings)
101
102         if (o1 == null && o2 == null) {
103             return Boolean.TRUE;
104         }
105         else if (o1 != null) {
106             // BigDecimals must be compared using compareTo (
107 // see CAY-280 and BigDecimal.equals JavaDoc)
108 if (o1 instanceof BigDecimal JavaDoc) {
109                 if (o2 instanceof BigDecimal JavaDoc) {
110                     return ((BigDecimal JavaDoc) o1).compareTo((BigDecimal JavaDoc) o2) == 0
111                             ? Boolean.TRUE
112                             : Boolean.FALSE;
113                 }
114
115                 return Boolean.FALSE;
116             }
117
118             return o1.equals(o2) ? Boolean.TRUE : Boolean.FALSE;
119         }
120         else {
121             return Boolean.FALSE;
122         }
123     }
124
125     /**
126      * Creates a copy of this expression node, without copying children.
127      */
128     public Expression shallowCopy() {
129         return new ASTEqual(id);
130     }
131
132     protected String JavaDoc getExpressionOperator(int index) {
133         return "=";
134     }
135
136     public int getType() {
137         return Expression.EQUAL_TO;
138     }
139 }
140
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