com.hazelcast.core

Interface Cluster

All Known Implementing Classes:

ClientClusterProxy, ClusterProxy

public interface Cluster

Hazelcast cluster interface. It provides access to the members in the cluster and one can register for changes in the cluster members.

All the methods on the Cluster are thread-safe.

Method Summary

Methods

Modifier and Type	Method and Description
String	addMembershipListener(MembershipListener listener) Adds MembershipListener to listen for membership updates.
long	getClusterTime() Returns the cluster-wide time in milliseconds.
Member	getLocalMember() Returns this Hazelcast instance member
Set<Member>	getMembers() Set of current members of the cluster.
boolean	removeMembershipListener(String registrationId) Removes the specified MembershipListener.

Method Detail

addMembershipListener

String addMembershipListener(MembershipListener listener)

Adds MembershipListener to listen for membership updates.

The addMembershipListener returns a register-id. This id is needed to remove the MembershipListener using the removeMembershipListener(String) method.

If the MembershipListener implements the InitialMembershipListener interface, it will also receive the InitialMembershipEvent.

There is no check for duplicate registrations, so if you register the listener twice, it will get events twice.

Parameters:

listener - membership listener

Returns:

the registration id.

Throws:

NullPointerException - if listener is null.

See Also:

removeMembershipListener(String)

removeMembershipListener

boolean removeMembershipListener(String registrationId)

Removes the specified MembershipListener.

If the same MembershipListener is registered multiple times, it needs to be removed multiple times. This method can safely be called multiple times for the same registration-id; every subsequent call is just ignored.

Parameters:

registrationId - the registrationId of MembershipListener to remove.

Returns:

true if registration is removed, false otherwise.

Throws:

NullPointerException - if registration id is null.

See Also:

addMembershipListener(MembershipListener)

getMembers

Set<Member> getMembers()

Set of current members of the cluster. The returned set is an immutable set; so can't be modified.

The returned set is backed by an ordered set. Every member in the cluster returns the 'members' in the same order. To obtain the oldest member (the master) in the cluster, the first item in the set can be retrieved using 'getMembers().iterator().next()'.

Returns:

current members of the cluster

getLocalMember

Member getLocalMember()

Returns this Hazelcast instance member

Returns:

this Hazelcast instance member

getClusterTime

long getClusterTime()

Returns the cluster-wide time in milliseconds.

Cluster tries to keep a cluster-wide time which is might be different than the member's own system time. Cluster-wide time is -almost- the same on all members of the cluster.

Returns:

cluster-wide time