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Java > Open Source Codes > org > codehaus > groovy > ast > expr > ConstantExpression


1 /*
2  $Id: ConstantExpression.java,v 1.7 2004/07/10 03:31:37 bran Exp $
3
4  Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
5
6  Redistribution and use of this software and associated documentation
7  ("Software"), with or without modification, are permitted provided
8  that the following conditions are met:
9
10  1. Redistributions of source code must retain copyright
11     statements and notices. Redistributions must also contain a
12     copy of this document.
13
14  2. Redistributions in binary form must reproduce the
15     above copyright notice, this list of conditions and the
16     following disclaimer in the documentation and/or other
17     materials provided with the distribution.
18
19  3. The name "groovy" must not be used to endorse or promote
20     products derived from this Software without prior written
21     permission of The Codehaus. For written permission,
22     please contact info@codehaus.org.
23
24  4. Products derived from this Software may not be called "groovy"
25     nor may "groovy" appear in their names without prior written
26     permission of The Codehaus. "groovy" is a registered
27     trademark of The Codehaus.
28
29  5. Due credit should be given to The Codehaus -
30     http://groovy.codehaus.org/
31
32  THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
33  ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
34  NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
35  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
36  THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
37  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
38  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
39  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
40  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
43  OF THE POSSIBILITY OF SUCH DAMAGE.
44
45  */
46 package org.codehaus.groovy.ast.expr;
47
48 import org.codehaus.groovy.ast.GroovyCodeVisitor;
49 import org.codehaus.groovy.classgen.AsmClassGenerator2;
50
51 /**
52  * Represents a constant expression such as null, true, false
53  *
54  * @author <a HREF="mailto:james@coredevelopers.net">James Strachan</a>
55  * @version $Revision: 1.7 $
56  */
57 public class ConstantExpression extends Expression {
58     public static final ConstantExpression VOID = new ConstantExpression(Void JavaDoc.class);
59     public static final ConstantExpression NULL = new ConstantExpression(null);
60     public static final ConstantExpression TRUE = new ConstantExpression(Boolean.TRUE);
61     public static final ConstantExpression FALSE = new ConstantExpression(Boolean.FALSE);
62     public static final ConstantExpression EMPTY_STRING = new ConstantExpression("");
63     //public static final Expression EMPTY_ARRAY = new PropertyExpression(new ClassExpression(ArgumentListExpression.class.getName()), "EMPTY_ARRAY");
64
65     private Object JavaDoc value;
66     
67     public ConstantExpression(Object JavaDoc value) {
68         this.value = value;
69         if (this.value != null)
70             setTypeClass(value.getClass());
71     }
72
73     public String JavaDoc toString() {
74         return super.toString() +"[value=" + value + "]";
75     }
76
77     public void visit(GroovyCodeVisitor visitor) {
78         visitor.visitConstantExpression(this);
79     }
80
81
82     public Expression transformExpression(ExpressionTransformer transformer) {
83         return this;
84     }
85
86     protected void resolveType(AsmClassGenerator2 resolver) {
87         //
88 }
89
90     /**
91      * @return the value of this constant expression
92      */
93     public Object JavaDoc getValue() {
94         return value;
95     }
96
97     public String JavaDoc getText() {
98         return (value == null) ? "null" : value.toString();
99     }
100 }
101
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