001    /*
002     $Id: MethodCallExpression.java 4287 2006-12-01 13:00:13Z 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 groovy.lang.MetaMethod;
049    
050    import org.codehaus.groovy.ast.ClassHelper;
051    import org.codehaus.groovy.ast.GroovyCodeVisitor;
052    
053    /**
054     * A method call on an object or class
055     * 
056     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
057     * @version $Revision: 4287 $
058     */
059    public class MethodCallExpression extends Expression {
060    
061        private Expression objectExpression;
062        private Expression method;
063        private Expression arguments;
064        private boolean spreadSafe = false;
065        private boolean safe = false;
066        private boolean implicitThis;
067        
068        public static Expression NO_ARGUMENTS = new TupleExpression();
069    
070        public MetaMethod getMetaMethod() {
071            return metaMethod;
072        }
073    
074        private MetaMethod metaMethod = null;
075    
076        public MethodCallExpression(Expression objectExpression, String method, Expression arguments) {
077            this(objectExpression,new ConstantExpression(method),arguments);
078        }
079        
080        public MethodCallExpression(Expression objectExpression, Expression method, Expression arguments) {
081            this.objectExpression = objectExpression;
082            this.method = method;
083            this.arguments = arguments;
084            //TODO: set correct type here
085            // if setting type and a methodcall is the last expresssion in a method,
086            // then the method will return null if the method itself is not void too!
087            // (in bytecode after call: aconst_null, areturn)
088            this.setType(ClassHelper.DYNAMIC_TYPE);
089            this.setImplicitThis(true);
090        }
091    
092        public void visit(GroovyCodeVisitor visitor) {
093            visitor.visitMethodCallExpression(this);
094        }
095    
096        public Expression transformExpression(ExpressionTransformer transformer) {
097            MethodCallExpression answer =
098                new MethodCallExpression(transformer.transform(objectExpression), transformer.transform(method), transformer.transform(arguments));
099            answer.setSafe(safe);
100            answer.setSourcePosition(this);
101            return answer;
102        }
103    
104        public Expression getArguments() {
105            return arguments;
106        }
107    
108        public Expression getMethod() {
109            return method;
110        }
111        
112        /**
113         * This method returns the method name as String if it is no dynamic
114         * calculated method name, but an constant.
115         */
116        public String getMethodAsString() {
117            if (! (method instanceof ConstantExpression)) return null;
118            ConstantExpression constant = (ConstantExpression) method;
119            return constant.getText();
120        }
121    
122        public Expression getObjectExpression() {
123            return objectExpression;
124        }
125    
126        public String getText() {
127            return objectExpression.getText() + "." + method.getText() + arguments.getText();
128        }
129    
130        /**
131         * @return is this a safe method call, i.e. if true then if the source object is null
132         * then this method call will return null rather than throwing a null pointer exception
133         */
134        public boolean isSafe() {
135            return safe;
136        }
137    
138        public void setSafe(boolean safe) {
139            this.safe = safe;
140        }
141    
142        public boolean isSpreadSafe() {
143            return spreadSafe;
144        }
145    
146        public void setSpreadSafe(boolean value) {
147            spreadSafe = value;
148        }
149    
150        /**
151         * @return true if no object expression was specified otherwise if 
152         * some expression was specified for the object on which to evaluate
153         * the method then return false
154         */
155        public boolean isImplicitThis() {
156            return implicitThis;
157        }
158    
159        public void setImplicitThis(boolean implicitThis) {
160            this.implicitThis = implicitThis;
161        }
162    
163        public String toString() {
164            return super.toString()
165                + "[object: "
166                + objectExpression
167                + " method: "
168                + method
169                + " arguments: "
170                + arguments
171                + "]";
172        }
173    
174        public void setMethod(MetaMethod mmeth) {
175            this.metaMethod = mmeth;
176            super.setType(ClassHelper.make(mmeth.getReturnType()));
177        }
178    }