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Java > Open Source Codes > org > apache > cayenne > exp > parser > ASTScalar


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19
20 package org.apache.cayenne.exp.parser;
21
22 import java.io.PrintWriter JavaDoc;
23
24 import org.apache.cayenne.exp.Expression;
25
26 /**
27  * A scalar value wrapper expression.
28  *
29  * @since 1.1
30  * @author Andrus Adamchik
31  */
32 public class ASTScalar extends SimpleNode {
33     protected Object JavaDoc value;
34
35     /**
36      * Constructor used by expression parser. Do not invoke directly.
37      */
38     ASTScalar(int id) {
39         super(id);
40     }
41
42     public ASTScalar() {
43         super(ExpressionParserTreeConstants.JJTSCALAR);
44     }
45
46     public ASTScalar(Object JavaDoc value) {
47         super(ExpressionParserTreeConstants.JJTSCALAR);
48         setValue(value);
49     }
50
51     protected Object JavaDoc evaluateNode(Object JavaDoc o) throws Exception JavaDoc {
52         return value;
53     }
54
55     /**
56      * Creates a copy of this expression node, without copying children.
57      */
58     public Expression shallowCopy() {
59         ASTScalar copy = new ASTScalar(id);
60         copy.value = value;
61         return copy;
62     }
63
64     public void encodeAsString(PrintWriter JavaDoc pw) {
65         SimpleNode.encodeScalarAsString(pw, value);
66     }
67
68     public void setValue(Object JavaDoc value) {
69         this.value = value;
70     }
71
72     public Object JavaDoc getValue() {
73         return value;
74     }
75
76     protected String JavaDoc getExpressionOperator(int index) {
77         throw new UnsupportedOperationException JavaDoc(
78             "No operator for '" + ExpressionParserTreeConstants.jjtNodeName[id] + "'");
79     }
80 }
81
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