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Java > Open Source Codes > org > fjank > jcache > distribution > JGroupsDistributionEngine


1 /* Open Source Java Caching Service
2 * Copyright (C) 2002 Frank Karlstrøm
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public
5 * License as published by the Free Software Foundation; either
6 * version 2.1 of the License, or (at your option) any later version.
7 *
8 * This library is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * Lesser General Public License for more details.
12 *
13 * You should have received a copy of the GNU Lesser General Public
14 * License along with this library; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16 *
17 * The author can be contacted by email: fjankk@users.sourceforge.net
18 */
19 package org.fjank.jcache.distribution;
20
21 import java.util.Enumeration JavaDoc;
22 import org.fjank.jcache.CacheImpl;
23 import org.jgroups.Address;
24 import org.jgroups.ChannelClosedException;
25 import org.jgroups.ChannelException;
26 import org.jgroups.ChannelNotConnectedException;
27 import org.jgroups.JChannel;
28 import org.jgroups.Membership;
29 import org.jgroups.MembershipListener;
30 import org.jgroups.Message;
31 import org.jgroups.MessageListener;
32 import org.jgroups.View;
33 import org.jgroups.blocks.PullPushAdapter;
34
35 public class JGroupsDistributionEngine
36     extends DistributionEngine
37     implements MessageListener, MembershipListener
38 {
39     private static JGroupsDistributionEngine _singleton;
40
41     public static synchronized JGroupsDistributionEngine instanceOf(CacheImpl cache)
42     {
43         if (_singleton == null)
44         {
45             _singleton = new JGroupsDistributionEngine(cache);
46         }
47         return _singleton;
48     }
49
50     private JChannel channel;
51
52     private Membership members = new Membership();
53     
54
55     private JGroupsDistributionEngine(CacheImpl cache)
56         
57     {
58         this.cache = cache;
59         if (cache.getAttributes().isDistributed())
60         {
61             try
62             {
63                 channel = new JChannel(null);
64                 channel.connect("FKacheOS");
65                 new PullPushAdapter(channel, this, this);
66             }
67             catch (ChannelException e)
68             {
69                 throw new IllegalStateException JavaDoc(e.getMessage());
70             }
71         }
72
73     }
74
75     public void block()
76     {
77     }
78
79     /**
80      *
81      */
82     public Enumeration JavaDoc getCacheAddr()
83     {
84         return members.getMembers().elements();
85     }
86
87     protected JChannel getChannel()
88     {
89         return channel;
90     }
91
92     /**
93      * state not currently in use.
94      */
95     public byte[] getState()
96     {
97         return new byte[0];
98     }
99
100     public void receive(Message msg)
101     {
102         // Only process messages coming from other members in the group
103 if (msg.getObject() instanceof ClusterNotification
104             && !msg.getSrc().equals(channel.getLocalAddress()))
105         {
106             ClusterNotification clusterNotification =
107                 (ClusterNotification) msg.getObject();
108             handleClusterNotification(clusterNotification);
109         }
110     }
111
112     public void sendNotification(ClusterNotification clusterNotification)
113        
114     {
115         if (cache.getAttributes().isDistributed())
116         {
117             Message message = new Message();
118             message.setObject(clusterNotification);
119             try
120             {
121                 channel.send(message);
122             }
123             catch (ChannelNotConnectedException e)
124             {
125                 throw new IllegalStateException JavaDoc(e.getMessage());
126             }
127             catch (ChannelClosedException e)
128             {
129                 throw new IllegalStateException JavaDoc(e.getMessage());
130             }
131         }
132     }
133
134     /**
135      * state not currently in use.
136      */
137     public void setState(byte[] state)
138     {
139
140     }
141
142     public void suspect(Address suspected_mbr)
143     {
144     }
145
146     /** Is called when new members arrives or leaves the group.
147      * @see org.jgroups.MembershipListener#viewAccepted(org.jgroups.View)
148      */
149     public void viewAccepted(View new_view)
150     {
151         members.add(new_view.getMembers());
152     }
153 }
154
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