org.jgroups.stack

Interface MembershipChangePolicy

All Known Implementing Classes:

GMS.DefaultMembershipPolicy, LargestWinningPolicy

public interface MembershipChangePolicy

Policy used to determine the new membership after a membership change (join, leave) or a merge. Can be installed in GMS to override the default policy, which adds new members at the end on a regular membership change, and adds all subviews into a new membership which is lexically sorted in case of a merge.

Since:

3.4

Author:

Bela Ban

Method Summary

Modifier and Type	Method and Description
java.util.List<Address>	getNewMembership(java.util.Collection<Address> current_members, java.util.Collection<Address> joiners, java.util.Collection<Address> leavers, java.util.Collection<Address> suspects) Computes a new membership based on existing, joining, leaving and suspected members.
java.util.List<Address>	getNewMembership(java.util.Collection<java.util.Collection<Address>> subviews) Compute a new membership based on a number of subviews

Method Detail

getNewMembership

java.util.List<Address> getNewMembership(java.util.Collection<Address> current_members,
                                         java.util.Collection<Address> joiners,
                                         java.util.Collection<Address> leavers,
                                         java.util.Collection<Address> suspects)

Computes a new membership based on existing, joining, leaving and suspected members. The first element of the new membership will be the coordinator.

Parameters:

current_members - The list of current members. Guaranteed to be non-null (but may be empty)

joiners - The joining members. Guaranteed to be non-null (but may be empty)

leavers - Members that are leaving. Guaranteed to be non-null (but may be empty)

suspects - Members which are suspected. Guaranteed to be non-null (but may be empty)

Returns:

The new membership. The first element of the list is the (old or existing) coordinator. There cannot be any duplicate members

getNewMembership

java.util.List<Address> getNewMembership(java.util.Collection<java.util.Collection<Address>> subviews)

Compute a new membership based on a number of subviews

Parameters:

subviews - A list of membership lists, e.g. [{A,B,C}, {M,N,O,P}, {X,Y,Z}]. This is a merge between 3 subviews. Guaranteed to be non-null (but may be empty)

Returns:

The new membership. The first element of the list is the (old or existing) coordinator. There cannot be any duplicate members