001 /* 002 $Id: ConstantExpression.java 3264 2005-12-14 16:51:43Z blackdrag $ 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: 3264 $ 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 public static final ConstantExpression EMTPY_EXPRESSION = new ConstantExpression(null); 065 066 private Object value; 067 068 public ConstantExpression(Object value) { 069 this.value = value; 070 if (this.value != null) 071 setType(ClassHelper.make(value.getClass())); 072 } 073 074 public String toString() { 075 return super.toString() +"[value=" + value + "]"; 076 } 077 078 public void visit(GroovyCodeVisitor visitor) { 079 visitor.visitConstantExpression(this); 080 } 081 082 083 public Expression transformExpression(ExpressionTransformer transformer) { 084 return this; 085 } 086 087 /** 088 * @return the value of this constant expression 089 */ 090 public Object getValue() { 091 return value; 092 } 093 094 public String getText() { 095 return (value == null) ? "null" : value.toString(); 096 } 097 }