View Javadoc

1   /*
2    * $Id: GString.java 4098 2006-10-10 16:09:48Z blackdrag $
3    * 
4    * Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
5    * 
6    * Redistribution and use of this software and associated documentation
7    * ("Software"), with or without modification, are permitted provided that the
8    * following conditions are met: 1. Redistributions of source code must retain
9    * copyright statements and notices. Redistributions must also contain a copy
10   * of this document. 2. Redistributions in binary form must reproduce the above
11   * copyright notice, this list of conditions and the following disclaimer in
12   * the documentation and/or other materials provided with the distribution. 3.
13   * The name "groovy" must not be used to endorse or promote products derived
14   * from this Software without prior written permission of The Codehaus. For
15   * written permission, please contact info@codehaus.org. 4. Products derived
16   * from this Software may not be called "groovy" nor may "groovy" appear in
17   * their names without prior written permission of The Codehaus. "groovy" is a
18   * registered trademark of The Codehaus. 5. Due credit should be given to The
19   * Codehaus - http://groovy.codehaus.org/
20   * 
21   * THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS ``AS IS'' AND ANY
22   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
24   * DISCLAIMED. IN NO EVENT SHALL THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR
25   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
27   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
28   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
31   * DAMAGE.
32   *  
33   */
34  package groovy.lang;
35  
36  import java.io.IOException;
37  import java.io.StringWriter;
38  import java.io.Writer;
39  import java.util.ArrayList;
40  import java.util.Arrays;
41  import java.util.List;
42  import java.util.regex.Pattern;
43  
44  import org.codehaus.groovy.runtime.DefaultGroovyMethods;
45  import org.codehaus.groovy.runtime.InvokerHelper;
46  
47  /***
48   * Represents a String which contains embedded values such as "hello there
49   * ${user} how are you?" which can be evaluated lazily. Advanced users can
50   * iterate over the text and values to perform special processing, such as for
51   * performing SQL operations, the values can be substituted for ? and the
52   * actual value objects can be bound to a JDBC statement. The lovely name of
53   * this class was suggested by Jules Gosnell and was such a good idea, I
54   * couldn't resist :)
55   * 
56   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
57   * @version $Revision: 4098 $
58   */
59  public abstract class GString extends GroovyObjectSupport implements Comparable, CharSequence, Writable, Buildable {
60  
61      private Object[] values;
62  
63      public GString(Object values) {
64          this.values = (Object[]) values;
65      }
66  
67      public GString(Object[] values) {
68          this.values = values;
69      }
70  
71      // will be static in an instance
72      public abstract String[] getStrings();
73  
74      /***
75       * Overloaded to implement duck typing for Strings 
76       * so that any method that can't be evaluated on this
77       * object will be forwarded to the toString() object instead.
78       */
79      public Object invokeMethod(String name, Object args) {
80          try {
81              return super.invokeMethod(name, args);
82          }
83          catch (MissingMethodException e) {
84              // lets try invoke the method on the real String
85              return InvokerHelper.invokeMethod(toString(), name, args);
86          }
87      }
88  
89      public Object[] getValues() {
90          return values;
91      }
92  
93      public GString plus(GString that) {
94          List stringList = new ArrayList();
95          List valueList = new ArrayList();
96  
97          stringList.addAll(Arrays.asList(getStrings()));
98          valueList.addAll(Arrays.asList(getValues()));
99  
100         if (stringList.size() > valueList.size()) {
101             valueList.add("");
102         }
103 
104         stringList.addAll(Arrays.asList(that.getStrings()));
105         valueList.addAll(Arrays.asList(that.getValues()));
106 
107         final String[] newStrings = new String[stringList.size()];
108         stringList.toArray(newStrings);
109         Object[] newValues = valueList.toArray();
110 
111         return new GString(newValues) {
112             public String[] getStrings() {
113                 return newStrings;
114             }
115         };
116     }
117 
118     public GString plus(String that) {
119         String[] currentStrings = getStrings();
120         String[] newStrings = null;
121         Object[] newValues = null;
122 
123         newStrings = new String[currentStrings.length + 1];
124         newValues = new Object[getValues().length + 1];
125         int lastIndex = currentStrings.length;
126         System.arraycopy(currentStrings, 0, newStrings, 0, lastIndex);
127         System.arraycopy(getValues(), 0, newValues, 0, getValues().length);
128         newStrings[lastIndex] = that;
129         newValues[getValues().length] = "";
130 
131         final String[] finalStrings = newStrings;
132         return new GString(newValues) {
133 
134             public String[] getStrings() {
135                 return finalStrings;
136             }
137         };
138     }
139 
140     public int getValueCount() {
141         return values.length;
142     }
143 
144     public Object getValue(int idx) {
145         return values[idx];
146     }
147 
148     public String toString() {
149         StringWriter buffer = new StringWriter();
150         try {
151             writeTo(buffer);
152         }
153         catch (IOException e) {
154             throw new StringWriterIOException(e);
155         }
156         return buffer.toString();
157     }
158 
159     public Writer writeTo(Writer out) throws IOException {
160         String[] s = getStrings();
161         int numberOfValues = values.length;
162         for (int i = 0, size = s.length; i < size; i++) {
163             out.write(s[i]);
164             if (i < numberOfValues) {
165                 InvokerHelper.write(out, values[i]);
166             }
167         }
168         return out;
169     }
170 
171     /* (non-Javadoc)
172      * @see groovy.lang.Buildable#build(groovy.lang.GroovyObject)
173      */
174     public void build(final GroovyObject builder) {
175     final String[] s = getStrings();
176     final int numberOfValues = values.length;
177         
178         for (int i = 0, size = s.length; i < size; i++) {
179             builder.getProperty("mkp");
180             builder.invokeMethod("yield", new Object[]{s[i]});
181             if (i < numberOfValues) {
182                 builder.getProperty("mkp");
183                 builder.invokeMethod("yield", new Object[]{values[i]});
184             }
185         }
186     }
187 
188     public boolean equals(Object that) {
189         if (that instanceof GString) {
190             return equals((GString) that);
191         }
192         return false;
193     }
194 
195     public boolean equals(GString that) {
196         return toString().equals(that.toString());
197     }
198 
199     public int hashCode() {
200         return 37 + toString().hashCode();
201     }
202 
203     public int compareTo(Object that) {
204         return toString().compareTo(that.toString());
205     }
206 
207     public char charAt(int index) {
208         return toString().charAt(index);
209     }
210 
211     public int length() {
212         return toString().length();
213     }
214 
215     public CharSequence subSequence(int start, int end) {
216         return toString().subSequence(start, end);
217     }
218 
219     /***
220      * Turns a String into a regular expression pattern
221      *
222      * @return the regular expression pattern
223      */
224     public Pattern negate() {
225         return DefaultGroovyMethods.negate(toString());
226     }
227 }