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Java > Open Source Codes > org > jboss > ha > singleton > HASingletonElectionPolicyMBean


1 /*
2   * JBoss, Home of Professional Open Source
3   * Copyright 2005, JBoss Inc., and individual contributors as indicated
4   * by the @authors tag. See the copyright.txt in the distribution for a
5   * full listing of individual contributors.
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7   * This is free software; you can redistribute it and/or modify it
8   * under the terms of the GNU Lesser General Public License as
9   * 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.singleton;
23
24
25 import org.jboss.ha.framework.interfaces.ClusterNode;
26 import org.jboss.ha.framework.interfaces.HAPartition;
27
28 /**
29  * Management Bean for HASinigleton Election Policy.
30
31  * @author <a HREF="mailto:Alex.Fu@novell.com">Alex Fu</a>.
32  * @version $Revision: 46010 $
33  *
34  */
35 public interface HASingletonElectionPolicyMBean
36    extends org.jboss.system.ServiceMBean
37 {
38    /**
39     * Called by the HASingleton to provide the election policy a reference to
40     * itself. A policy that was designed to elect a particular kind of singleton
41     * could downcast this object to a particular type and then access the
42     * singleton for state information needed for the election decision.
43     */
44    void setManagedSingleton(Object JavaDoc singleton);
45    Object JavaDoc getManagedSingleton();
46
47    /**
48     * Sets the HAPartition; from this the election policy can gain
49     * access to the DistributedReplicantManager for tracking the
50     * deployment topology for the singleton service and to the HAPartition
51     * for making group RPC calls.
52     */
53    void setHAPartition(HAPartition partition);
54    HAPartition getHAPartition();
55
56    /**
57     * Return the elected master node.
58     * @return the master node
59     */
60    ClusterNode pickSingleton();
61    
62    /**
63     * Given the HAPartition, return the elected master node.
64     * @param partition
65     * @return the master node
66     */
67    ClusterNode pickSingleton(HAPartition partition);
68    
69    /**
70     * Conducts an election and returns whether the managed service
71     * is the master, based on the current view of partition.
72     * @return true only if the managed service is the master
73     */
74    public boolean isElectedMaster();
75    
76    /**
77     * Given the HAPartition, return whether the managed service is the master.
78     * @param partition
79     * @return true only if the managed service is the master
80     */
81    public boolean isElectedMaster(HAPartition partiton);
82 }
83
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