001 /* 002 $Id: ConstantExpression.java,v 1.10 2005/11/13 16:42:09 blackdrag Exp $ 003 004 Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved. 005 006 Redistribution and use of this software and associated documentation 007 ("Software"), with or without modification, are permitted provided 008 that the following conditions are met: 009 010 1. Redistributions of source code must retain copyright 011 statements and notices. Redistributions must also contain a 012 copy of this document. 013 014 2. Redistributions in binary form must reproduce the 015 above copyright notice, this list of conditions and the 016 following disclaimer in the documentation and/or other 017 materials provided with the distribution. 018 019 3. The name "groovy" must not be used to endorse or promote 020 products derived from this Software without prior written 021 permission of The Codehaus. For written permission, 022 please contact info@codehaus.org. 023 024 4. Products derived from this Software may not be called "groovy" 025 nor may "groovy" appear in their names without prior written 026 permission of The Codehaus. "groovy" is a registered 027 trademark of The Codehaus. 028 029 5. Due credit should be given to The Codehaus - 030 http://groovy.codehaus.org/ 031 032 THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS 033 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT 034 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 035 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 036 THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 037 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 038 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 039 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 040 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 041 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 042 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 043 OF THE POSSIBILITY OF SUCH DAMAGE. 044 045 */ 046 package org.codehaus.groovy.ast.expr; 047 048 import org.codehaus.groovy.ast.ClassHelper; 049 import org.codehaus.groovy.ast.GroovyCodeVisitor; 050 051 /** 052 * Represents a constant expression such as null, true, false 053 * 054 * @author <a href="mailto:james@coredevelopers.net">James Strachan</a> 055 * @version $Revision: 1.10 $ 056 */ 057 public class ConstantExpression extends Expression { 058 public static final ConstantExpression VOID = new ConstantExpression(Void.class); 059 public static final ConstantExpression NULL = new ConstantExpression(null); 060 public static final ConstantExpression TRUE = new ConstantExpression(Boolean.TRUE); 061 public static final ConstantExpression FALSE = new ConstantExpression(Boolean.FALSE); 062 public static final ConstantExpression EMPTY_STRING = new ConstantExpression(""); 063 //public static final Expression EMPTY_ARRAY = new PropertyExpression(new ClassExpression(ArgumentListExpression.class.getName()), "EMPTY_ARRAY"); 064 065 private Object value; 066 067 public ConstantExpression(Object value) { 068 this.value = value; 069 if (this.value != null) 070 setType(ClassHelper.make(value.getClass())); 071 } 072 073 public String toString() { 074 return super.toString() +"[value=" + value + "]"; 075 } 076 077 public void visit(GroovyCodeVisitor visitor) { 078 visitor.visitConstantExpression(this); 079 } 080 081 082 public Expression transformExpression(ExpressionTransformer transformer) { 083 return this; 084 } 085 086 /** 087 * @return the value of this constant expression 088 */ 089 public Object getValue() { 090 return value; 091 } 092 093 public String getText() { 094 return (value == null) ? "null" : value.toString(); 095 } 096 }