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 org.jboss.invocation.Invocation;
25:
26: /**
27: * Base interface for load-balancing policies. It is possible to implement many
28: * different load-balancing policies by implementing this simple interface and
29: * using it in the different clustered services (home interface of SLSB for
30: * example)
31: *
32: * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>.
33: * @author <a href="mailto:sacha.labourey@cogito-info.ch">Sacha Labourey</a>.
34: * @version $Revision: 57188 $
35: */
36: public interface LoadBalancePolicy extends java.io.Serializable {
37: /** The serialVersionUID
38: * @since 1.3.4.2
39: */
40: static final long serialVersionUID = -5071668971774090555L;
41:
42: /**
43: * Initialize the policy with a reference to its parent stub. the load-balancing policy
44: * implementation can use HARMIClient data to take its decision
45: * @param father The stub that owns the policy
46: */
47: public void init(HARMIClient father);
48:
49: /**
50: * Called when the stub wishes to know on which node the next invocation must
51: * be performed.
52: * @param clusterFamily A list of potential target nodes
53: * @return The selected target for the next invocation
54: */
55: public Object chooseTarget(FamilyClusterInfo clusterFamily);
56:
57: /**
58: * Called when the stub wishes to know on which node the next invocation must
59: * be performed.
60: * @param clusterFamily A list of potential target nodes
61: * @param routingDecision The actual invocation object if the policy wants
62: * to have some kind of invocation-based routing strategy
63: * @return The selected target for the next invocation
64: */
65: public Object chooseTarget(FamilyClusterInfo clusterFamily,
66: Invocation routingDecision);
67: }
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