001    /*
002     $Id: GStringExpression.java,v 1.14 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 java.util.ArrayList;
049    import java.util.Iterator;
050    import java.util.List;
051    
052    import org.codehaus.groovy.ast.ClassHelper;
053    import org.codehaus.groovy.ast.GroovyCodeVisitor;
054    
055    /**
056     * Represents a String expression which contains embedded values inside
057     * it such as "hello there ${user} how are you" which is expanded lazily
058     * 
059     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
060     * @version $Revision: 1.14 $
061     */
062    public class GStringExpression extends Expression {
063    
064        private String verbatimText;
065        private List strings = new ArrayList();
066        private List values = new ArrayList();
067        
068        public GStringExpression(String verbatimText) {
069            this.verbatimText = verbatimText;
070            super.setType(ClassHelper.GSTRING_TYPE);
071        }
072    
073        public GStringExpression(String verbatimText, List strings, List values) {
074            this.verbatimText = verbatimText;
075            this.strings = strings;
076            this.values = values;
077            super.setType(ClassHelper.GSTRING_TYPE);
078        }
079    
080        public void visit(GroovyCodeVisitor visitor) {
081            visitor.visitGStringExpression(this);
082        }
083    
084        public Expression transformExpression(ExpressionTransformer transformer) {
085            return new GStringExpression(
086                verbatimText,
087                transformExpressions(strings, transformer),
088                transformExpressions(values, transformer));
089        }
090    
091        public String toString() {
092            return super.toString() + "[strings: " + strings + " values: " + values + "]";
093        }
094    
095        public String getText() {
096            return verbatimText;
097        }
098    
099        public List getStrings() {
100            return strings;
101        }
102    
103        public List getValues() {
104            return values;
105        }
106    
107        public void addString(ConstantExpression text) {
108            if (text == null) {
109                throw new NullPointerException("Cannot add a null text expression");
110            }
111            strings.add(text);
112        }
113    
114        public void addValue(Expression value) {
115            // If the first thing is an value, then we need a dummy empty string in front of it so that when we
116            // toString it they come out in the correct order.
117            if (strings.size() == 0)
118                strings.add(ConstantExpression.EMPTY_STRING);
119            values.add(value);
120        }
121    
122        public Expression getValue(int idx) {
123            return (Expression) values.get(idx);
124        }
125    
126        public boolean isConstantString() {
127            return values.isEmpty();
128        }
129    
130        public Expression asConstantString() {
131            StringBuffer buffer = new StringBuffer();
132            for (Iterator iter = strings.iterator(); iter.hasNext();) {
133                ConstantExpression expression = (ConstantExpression) iter.next();
134                Object value = expression.getValue();
135                if (value != null) {
136                    buffer.append(value);
137                }
138            }
139            return new ConstantExpression(buffer.toString());
140        }
141    }