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Java > Open Source Codes > org > apache > commons > jexl > parser > ASTNotNode


1 /*
2  * Copyright 2002-2006 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.commons.jexl.parser;
17
18 import org.apache.commons.jexl.JexlContext;
19 import org.apache.commons.jexl.util.Coercion;
20
21 /**
22  * Not : 'not' or '!'.
23  *
24  * @author <a HREF="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
25  * @version $Id: ASTNotNode.java 398270 2006-04-30 03:02:58Z dion $
26  */
27
28 public class ASTNotNode extends SimpleNode {
29     /**
30      * Create the node given an id.
31      *
32      * @param id node id.
33      */
34     public ASTNotNode(int id) {
35         super(id);
36     }
37
38     /**
39      * Create a node with the given parser and id.
40      *
41      * @param p a parser.
42      * @param id node id.
43      */
44     public ASTNotNode(Parser p, int id) {
45         super(p, id);
46     }
47
48     /** {@inheritDoc} */
49     public Object JavaDoc jjtAccept(ParserVisitor visitor, Object JavaDoc data) {
50         return visitor.visit(this, data);
51     }
52
53     /** {@inheritDoc} */
54     public Object JavaDoc value(JexlContext jc) throws Exception JavaDoc {
55         Object JavaDoc val = ((SimpleNode) jjtGetChild(0)).value(jc);
56
57         /*
58          * coercion rules
59          */
60
61         Boolean JavaDoc b = Coercion.coerceBoolean(val);
62
63         if (b != null) {
64             return b.booleanValue() ? Boolean.FALSE : Boolean.TRUE;
65         }
66
67         throw new Exception JavaDoc("expression not boolean valued");
68     }
69
70 }
71
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