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


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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 import org.apache.cayenne.util.ConversionUtil;
26
27 /**
28  * "Not" expression.
29  *
30  * @since 1.1
31  * @author Andrus Adamchik
32  */
33 public class ASTNot extends AggregateConditionNode {
34
35     ASTNot(int id) {
36         super(id);
37     }
38
39     public ASTNot() {
40         super(ExpressionParserTreeConstants.JJTNOT);
41     }
42
43     public ASTNot(Node expression) {
44         super(ExpressionParserTreeConstants.JJTNOT);
45         jjtAddChild(expression, 0);
46     }
47
48     protected Object JavaDoc evaluateNode(Object JavaDoc o) throws Exception JavaDoc {
49         int len = jjtGetNumChildren();
50         if (len == 0) {
51             return Boolean.FALSE;
52         }
53
54         return ConversionUtil.toBoolean(evaluateChild(0, o))
55             ? Boolean.FALSE
56             : Boolean.TRUE;
57     }
58
59     /**
60      * Creates a copy of this expression node, without copying children.
61      */
62     public Expression shallowCopy() {
63         return new ASTNot(id);
64     }
65
66     public int getType() {
67         return Expression.NOT;
68     }
69
70     public void encodeAsString(PrintWriter JavaDoc pw) {
71         pw.print("not ");
72         super.encodeAsString(pw);
73     }
74
75     protected String JavaDoc getExpressionOperator(int index) {
76         throw new UnsupportedOperationException JavaDoc(
77             "No operator for '" + ExpressionParserTreeConstants.jjtNodeName[id] + "'");
78     }
79 }
80
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