Switch


1   /*
2    * The Apache Software License, Version 1.1
3    *
4    * Copyright (c) 2001-2002 Ant-Contrib project.  All rights reserved.
5    *
6    * Redistribution and use in source and binary forms, with or without
7    * modification, are permitted provided that the following conditions
8    * are met:
9    *
10   * 1. Redistributions of source code must retain the above copyright
11   *    notice, this list of conditions and the following disclaimer. 
12   *
13   * 2. Redistributions in binary form must reproduce the above copyright
14   *    notice, this list of conditions and the following disclaimer in
15   *    the documentation and/or other materials provided with the
16   *    distribution.
17   *
18   * 3. The end-user documentation included with the redistribution, if
19   *    any, must include the following acknowlegement:  
20   *       "This product includes software developed by the 
21   *        Ant-Contrib project (http://sourceforge.net/projects/ant-contrib)."
22   *    Alternately, this acknowlegement may appear in the software itself,
23   *    if and wherever such third-party acknowlegements normally appear.
24   *
25   * 4. The name Ant-Contrib must not be used to endorse or promote products 
26   *    derived from this software without prior written permission. For
27   *    written permission, please contact
28   *    ant-contrib-developers@lists.sourceforge.net.
29   *
30   * 5. Products derived from this software may not be called "Ant-Contrib"
31   *    nor may "Ant-Contrib" appear in their names without prior written
32   *    permission of the Ant-Contrib project.
33   *
34   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
35   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
36   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
37   * DISCLAIMED.  IN NO EVENT SHALL THE ANT-CONTRIB PROJECT OR ITS
38   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
41   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
42   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
43   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
44   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
45   * SUCH DAMAGE.
46   * ====================================================================
47   */
48  package net.sf.antcontrib.logic;
49  
50  import org.apache.tools.ant.BuildException;
51  import org.apache.tools.ant.Task;
52  import org.apache.tools.ant.taskdefs.Sequential;
53  import java.util.Vector  ;
54  
55  /***
56   * Task definition for the ANT task to switch on a particular value.
57   *
58   * <pre>
59   *
60   * Usage:
61   *
62   *   Task declaration in the project:
63   *   <code>
64   *     &lt;taskdef name="switch" classname="net.sf.antcontrib.logic.Switch" /&gt;
65   *   </code>
66   *
67   *   Task calling syntax:
68   *    <code>
69   *     &lt;switch value="value" [caseinsensitive="true|false"] &gt;
70   *       &lt;case value="val"&gt;
71   *         &lt;property name="propname" value="propvalue" /&gt; |
72   *         &lt;antcall target="targetname" /&gt; |
73   *         any other tasks
74   *       &lt;/case&gt;
75   *      [
76   *       &lt;default&gt;
77   *         &lt;property name="propname" value="propvalue" /&gt; |
78   *         &lt;antcall target="targetname" /&gt; |
79   *         any other tasks
80   *       &lt;/default&gt; 
81   *      ]
82   *     &lt;/switch&gt;
83   *    </code>
84   *
85   *
86   *   Attributes:
87   *       value           -&gt; The value to switch on
88   *       caseinsensitive -&gt; Should we do case insensitive comparisons?
89   *                          (default is false)
90   *
91   *   Subitems:
92   *       case     --&gt; An individual case to consider, if the value that
93   *                    is being switched on matches to value attribute of
94   *                    the case, then the nested tasks will be executed.
95   *       default  --&gt; The default case for when no match is found.
96   *
97   * 
98   * Crude Example:
99   *
100  *     <code>
101  *     &lt;switch value=&quot;${foo}&quot;&gt;
102  *       &lt;case value=&quot;bar&quot;&gt;
103  *         &lt;echo message=&quot;The value of property foo is bar&quot; /&gt;
104  *       &lt;/case&gt;
105  *       &lt;case value=&quot;baz&quot;&gt;
106  *         &lt;echo message=&quot;The value of property foo is baz&quot; /&gt;
107  *       &lt;/case&gt;
108  *       &lt;default&gt;
109  *         &lt;echo message=&quot;The value of property foo is not sensible&quot; /&gt;
110  *       &lt;/default&gt;
111  *     &lt;/switch&gt;
112  *     </code>
113  *
114  * </pre>
115  *
116  * @author <a HREF="mailto:mattinger@mindless.com">Matthew Inger</a>
117  * @author <a HREF="mailto:stefan.bodewig@epost.de">Stefan Bodewig</a>
118  */
119 public class Switch extends Task
120 {
121     private String   value;
122     private Vector   cases;
123     private Sequential defaultCase;
124     private boolean caseInsensitive;
125     
126     /***
127      * Default Constructor
128      */
129     public Switch()
130     {
131         cases = new Vector  ();
132     }
133 
134     public void execute()
135         throws BuildException
136     {
137         if (value == null)
138             throw new BuildException("Value is missing");
139         if (cases.size() == 0 && defaultCase == null)
140             throw new BuildException("No cases supplied");
141 
142         Sequential selectedCase = defaultCase;
143 
144         int sz = cases.size();
145         for (int i=0;i<sz;i++)
146         {
147             Case c = (Case)(cases.elementAt(i));
148 
149             String   cvalue = c.value;
150             if (cvalue == null) {
151                 throw new BuildException("Value is required for case.");
152             }
153             String   mvalue = value;
154 
155             if (caseInsensitive)
156             {
157                 cvalue = cvalue.toUpperCase();
158                 mvalue = mvalue.toUpperCase();
159             }
160 
161             if (cvalue.equals(mvalue) && c != defaultCase)
162                 selectedCase = c;
163         }
164 
165         if (selectedCase == null) {
166             throw new BuildException("No case matched the value " + value
167                                      + " and no default has been specified.");
168         }
169         selectedCase.perform();
170     }
171 
172     /***
173      * Sets the value being switched on
174      */
175     public void setValue(String   value)
176     {
177         this.value = value;
178     }
179 
180     public void setCaseInsensitive(boolean c)
181     {
182         caseInsensitive = c;
183     }
184 
185     public final class Case extends Sequential
186     {
187         private String   value;
188 
189         public Case()
190         {
191             super();
192         }
193         
194         public void setValue(String   value)
195         {
196             this.value = value;
197         }
198 
199         public void execute()
200             throws BuildException
201         {
202             super.execute();
203         }
204 
205         public boolean equals(Object   o)
206         {
207             boolean res = false;
208             Case c = (Case)o;
209             if (c.value.equals(value))
210                 res = true;
211             return res;                
212         }
213     }
214 
215     /***
216      * Creates the &lt;case&gt; tag
217      */
218     public Switch.Case createCase()
219         throws BuildException
220     {
221         Switch.Case res = new Switch.Case();
222         cases.add(res);
223         return res;
224     }
225 
226     /***
227      * Creates the &lt;default&gt; tag
228      */
229     public void addDefault(Sequential res)
230         throws BuildException
231     {
232         if (defaultCase != null)
233             throw new BuildException("Cannot specify multiple default cases");
234 
235         defaultCase = res;
236     }
237 
238 }
239
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