org.jboss.ha.singleton
Class HASingletonElectionPolicySimple

java.lang.Object
  extended by org.jboss.ha.singleton.HASingletonElectionPolicySimple
All Implemented Interfaces:
org.jboss.ha.framework.interfaces.HASingletonElectionPolicy, HASingletonElectionPolicySimpleMBean
Direct Known Subclasses:
PreferredMasterElectionPolicy

public class HASingletonElectionPolicySimple
extends Object
implements org.jboss.ha.framework.interfaces.HASingletonElectionPolicy, HASingletonElectionPolicySimpleMBean

A simple concrete policy service that decides which node in the cluster should be the master node to run certain HASingleton service based on attribute "Position". The value will be divided by partition size and only remainder will be used. Let's say partition size is n: 0 means the first oldest node. 1 means the 2nd oldest node. ... n-1 means the nth oldest node. -1 means the youngest node. -2 means the 2nd youngest node. ... -n means the nth youngest node. E.g. the following attribute says the singleton will be running on the 3rd oldest node of the current partition: 2 If no election policy is defined, the oldest node in the cluster runs the singleton. This behaivour can be achieved with this policy when "position" is set to 0.

Version:
$Revision: 81001 $
Author:
Alex Fu, Galder Zamarreno

Constructor Summary
HASingletonElectionPolicySimple()
           
 
Method Summary
 org.jboss.ha.framework.interfaces.ClusterNode elect(List<org.jboss.ha.framework.interfaces.ClusterNode> candidates)
           
 int getPosition()
           
 void setPosition(int pos)
          Attribute: position.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

HASingletonElectionPolicySimple

public HASingletonElectionPolicySimple()
Method Detail

setPosition

public void setPosition(int pos)
Description copied from interface: HASingletonElectionPolicySimpleMBean
Attribute: position. 0 means the oldest node, 1 means 2nd oldest, ... -1 means the youngest node, -2 means 2nd youngest, ...

Specified by:
setPosition in interface HASingletonElectionPolicySimpleMBean
See Also:
HASingletonElectionPolicySimpleMBean.setPosition(int)

getPosition

public int getPosition()
Specified by:
getPosition in interface HASingletonElectionPolicySimpleMBean
See Also:
HASingletonElectionPolicySimpleMBean.getPosition()

elect

public org.jboss.ha.framework.interfaces.ClusterNode elect(List<org.jboss.ha.framework.interfaces.ClusterNode> candidates)
Specified by:
elect in interface org.jboss.ha.framework.interfaces.HASingletonElectionPolicy


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