01: /*
02: * JBoss, Home of Professional Open Source.
03: * Copyright 2006, Red Hat Middleware LLC, and individual contributors
04: * as indicated by the @author tags. See the copyright.txt file in the
05: * distribution for a full listing of individual contributors.
06: *
07: * This is free software; you can redistribute it and/or modify it
08: * under the terms of the GNU Lesser General Public License as
09: * published by the Free Software Foundation; either version 2.1 of
10: * the License, or (at your option) any later version.
11: *
12: * This software is distributed in the hope that it will be useful,
13: * but WITHOUT ANY WARRANTY; without even the implied warranty of
14: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15: * Lesser General Public License for more details.
16: *
17: * You should have received a copy of the GNU Lesser General Public
18: * License along with this software; if not, write to the Free
19: * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20: * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
21: */
22: package org.jboss.ha.framework.interfaces;
23:
24: import java.util.ArrayList;
25: import java.util.Random;
26:
27: import org.jboss.invocation.Invocation;
28:
29: /**
30: * LoadBalancingPolicy implementation that always fully randomly select its target
31: * (without basing its decision on any historic).
32: *
33: * @author <a href="mailto:sacha.labourey@cogito-info.ch">Sacha Labourey</a>.
34: * @version $Revision: 57188 $
35: * @see org.jboss.ha.framework.interfaces.LoadBalancePolicy
36: */
37: public class RandomRobin implements LoadBalancePolicy {
38: // Constants -----------------------------------------------------
39: /** @since 1.1.2.3 */
40: private static final long serialVersionUID = -3599638697906618428L;
41: /** This needs to be a class variable or else you end up with multiple
42: * Random numbers with the same seed when many clients lookup a proxy.
43: */
44: public static final Random localRandomizer = new Random(System
45: .currentTimeMillis());
46:
47: // Static --------------------------------------------------------
48:
49: // Constructors --------------------------------------------------
50:
51: // Public --------------------------------------------------------
52:
53: // LoadBalancePolicy implementation ----------------------------------------------
54:
55: public void init(HARMIClient father) {
56: // do not use the HARMIClient in this policy
57: }
58:
59: public Object chooseTarget(FamilyClusterInfo clusterFamily) {
60: return chooseTarget(clusterFamily, null);
61: }
62:
63: public Object chooseTarget(FamilyClusterInfo clusterFamily,
64: Invocation routingDecision) {
65: ArrayList targets = clusterFamily.getTargets();
66: int max = targets.size();
67:
68: if (max == 0)
69: return null;
70:
71: int cursor = localRandomizer.nextInt(max);
72: return targets.get(cursor);
73: }
74:
75: }
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