1 /***
2 * Redistribution and use in source and binary forms, with or without
3 * modification, are permitted provided that the following conditions are
4 * met :
5 *
6 * . Redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer.
8 *
9 * . Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * . The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
20 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
25 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 * $Id: Subject.java,v 1.3 2005/08/26 18:09:36 mat007 Exp $
29 */
30
31 package jtge.engine.handler;
32
33 import java.util.Iterator;
34 import java.util.Vector;
35 import jtge.engine.command.ICommand;
36
37 /***
38 * Provides a means to broadcast received commands to several consumers.
39 *
40 * @author Mathieu Champlon
41 * @version $Revision: 1.3 $ $Date: 2005/08/26 18:09:36 $
42 */
43 public class Subject implements IConsumer
44 {
45 private final Vector observers;
46
47 /***
48 * Create a subject.
49 */
50 public Subject()
51 {
52 observers = new Vector();
53 }
54
55 /***
56 * Register an observer.
57 * <p>
58 * If the consumer was previously registered this method has no effect.
59 *
60 * @param observer the consumer to register (should not be null)
61 */
62 public final void register( final IConsumer observer )
63 {
64 if( observer == null )
65 throw new IllegalArgumentException( "argument 'observer' is null." );
66 observers.add( observer );
67 }
68
69 /***
70 * Unregister an observer.
71 *
72 * @param observer the consumer to unregister
73 */
74 public final void unregister( final IConsumer observer )
75 {
76 observers.remove( observer );
77 }
78
79 /***
80 * {@inheritDoc}
81 */
82 public final void handle( final ICommand command )
83 {
84 Iterator iterator = ((Vector)observers.clone()).iterator();
85 while( iterator.hasNext() )
86 ((IConsumer)iterator.next()).handle( command );
87 }
88 }