001    /*
002     * $Id: GString.java,v 1.16 2005/11/04 08:33:57 tug 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 that the
008     * following conditions are met: 1. Redistributions of source code must retain
009     * copyright statements and notices. Redistributions must also contain a copy
010     * of this document. 2. Redistributions in binary form must reproduce the above
011     * copyright notice, this list of conditions and the following disclaimer in
012     * the documentation and/or other materials provided with the distribution. 3.
013     * The name "groovy" must not be used to endorse or promote products derived
014     * from this Software without prior written permission of The Codehaus. For
015     * written permission, please contact info@codehaus.org. 4. Products derived
016     * from this Software may not be called "groovy" nor may "groovy" appear in
017     * their names without prior written permission of The Codehaus. "groovy" is a
018     * registered trademark of The Codehaus. 5. Due credit should be given to The
019     * Codehaus - http://groovy.codehaus.org/
020     * 
021     * THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS ``AS IS'' AND ANY
022     * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
023     * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
024     * DISCLAIMED. IN NO EVENT SHALL THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR
025     * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
026     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
027     * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
028     * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
029     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
030     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
031     * DAMAGE.
032     *  
033     */
034    package groovy.lang;
035    
036    import java.io.IOException;
037    import java.io.StringWriter;
038    import java.io.Writer;
039    import java.util.ArrayList;
040    import java.util.Arrays;
041    import java.util.List;
042    import java.util.regex.Pattern;
043    
044    import org.codehaus.groovy.runtime.InvokerHelper;
045    
046    /**
047     * Represents a String which contains embedded values such as "hello there
048     * ${user} how are you?" which can be evaluated lazily. Advanced users can
049     * iterate over the text and values to perform special processing, such as for
050     * performing SQL operations, the values can be substituted for ? and the
051     * actual value objects can be bound to a JDBC statement. The lovely name of
052     * this class was suggested by Jules Gosnell and was such a good idea, I
053     * couldn't resist :)
054     * 
055     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
056     * @version $Revision: 1.16 $
057     */
058    public abstract class GString extends GroovyObjectSupport implements Comparable, CharSequence, Writable, Buildable {
059    
060        private Object[] values;
061    
062        public GString(Object values) {
063            this.values = (Object[]) values;
064        }
065    
066        public GString(Object[] values) {
067            this.values = values;
068        }
069    
070        // will be static in an instance
071        public abstract String[] getStrings();
072    
073        /**
074         * Overloaded to implement duck typing for Strings 
075         * so that any method that can't be evaluated on this
076         * object will be forwarded to the toString() object instead.
077         */
078        public Object invokeMethod(String name, Object args) {
079            try {
080                return super.invokeMethod(name, args);
081            }
082            catch (MissingMethodException e) {
083                // lets try invoke the method on the real String
084                return InvokerHelper.invokeMethod(toString(), name, args);
085            }
086        }
087    
088        public Object[] getValues() {
089            return values;
090        }
091    
092        public GString plus(GString that) {
093            List stringList = new ArrayList();
094            List valueList = new ArrayList();
095    
096            stringList.addAll(Arrays.asList(getStrings()));
097            valueList.addAll(Arrays.asList(getValues()));
098    
099            if (stringList.size() > valueList.size()) {
100                valueList.add("");
101            }
102    
103            stringList.addAll(Arrays.asList(that.getStrings()));
104            valueList.addAll(Arrays.asList(that.getValues()));
105    
106            final String[] newStrings = new String[stringList.size()];
107            stringList.toArray(newStrings);
108            Object[] newValues = valueList.toArray();
109    
110            return new GString(newValues) {
111                public String[] getStrings() {
112                    return newStrings;
113                }
114            };
115        }
116    
117        public GString plus(String that) {
118            String[] currentStrings = getStrings();
119            String[] newStrings = null;
120            Object[] newValues = null;
121    
122            newStrings = new String[currentStrings.length + 1];
123            newValues = new Object[getValues().length + 1];
124            int lastIndex = currentStrings.length;
125            System.arraycopy(currentStrings, 0, newStrings, 0, lastIndex);
126            System.arraycopy(getValues(), 0, newValues, 0, getValues().length);
127            newStrings[lastIndex] = that;
128            newValues[getValues().length] = "";
129    
130            final String[] finalStrings = newStrings;
131            return new GString(newValues) {
132    
133                public String[] getStrings() {
134                    return finalStrings;
135                }
136            };
137        }
138    
139        public int getValueCount() {
140            return values.length;
141        }
142    
143        public Object getValue(int idx) {
144            return values[idx];
145        }
146    
147        public String toString() {
148            StringWriter buffer = new StringWriter();
149            try {
150                writeTo(buffer);
151            }
152            catch (IOException e) {
153                throw new StringWriterIOException(e);
154            }
155            return buffer.toString();
156        }
157    
158        public Writer writeTo(Writer out) throws IOException {
159            String[] s = getStrings();
160            int numberOfValues = values.length;
161            for (int i = 0, size = s.length; i < size; i++) {
162                out.write(s[i]);
163                if (i < numberOfValues) {
164                    InvokerHelper.write(out, values[i]);
165                }
166            }
167            return out;
168        }
169    
170        /* (non-Javadoc)
171         * @see groovy.lang.Buildable#build(groovy.lang.GroovyObject)
172         */
173        public void build(final GroovyObject builder) {
174        final String[] s = getStrings();
175        final int numberOfValues = values.length;
176            
177            for (int i = 0, size = s.length; i < size; i++) {
178                builder.getProperty("mkp");
179                builder.invokeMethod("yield", new Object[]{s[i]});
180                if (i < numberOfValues) {
181                    builder.getProperty("mkp");
182                    builder.invokeMethod("yield", new Object[]{values[i]});
183                }
184            }
185        }
186    
187        public boolean equals(Object that) {
188            if (that instanceof GString) {
189                return equals((GString) that);
190            }
191            return false;
192        }
193    
194        public boolean equals(GString that) {
195            return toString().equals(that.toString());
196        }
197    
198        public int hashCode() {
199            return 37 + toString().hashCode();
200        }
201    
202        public int compareTo(Object that) {
203            return toString().compareTo(that.toString());
204        }
205    
206        public char charAt(int index) {
207            return toString().charAt(index);
208        }
209    
210        public int length() {
211            return toString().length();
212        }
213    
214        public CharSequence subSequence(int start, int end) {
215            return toString().subSequence(start, end);
216        }
217    
218        /**
219         * Turns a String into a regular expression pattern
220         *
221         * @return the regular expression pattern
222         */
223        public Pattern negate() {
224            return InvokerHelper.regexPattern(toString());
225        }
226    }