Package org.apache.catalina.tribes.membership

Class Membership

java.lang.Object

org.apache.catalina.tribes.membership.Membership

All Implemented Interfaces:

Cloneable

public class Membership
extends Object
implements Cloneable

A membership implementation using simple multicast. This is the representation of a multicast membership. This class is responsible for maintaining a list of active cluster nodes in the cluster. If a node fails to send out a heartbeat, the node will be dismissed.

Author:

Peter Rossbach

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	Membership.MbrEntry	Inner class that represents a member entry

Field Summary

Fields

Modifier and Type	Field	Description
protected static final Member[]	EMPTY_MEMBERS
protected final Member	local	The local member.
protected HashMap<Member,Membership.MbrEntry>	map	A map of all the members in the cluster.
protected final Comparator<Member>	memberComparator	Comparator for sorting members by alive time.
protected Member[]	members	A list of all the members in the cluster.

Constructor Summary

Constructors

Constructor	Description
Membership(Member local)
Membership(Member local, boolean includeLocal)	Constructs a new membership
Membership(Member local, Comparator<Member> comp)
Membership(Member local, Comparator<Member> comp, boolean includeLocal)

Method Summary

Modifier and Type	Method	Description
Membership.MbrEntry	addMember(Member member)	Add a member to this component and sort array with memberComparator
Membership	clone()
boolean	contains(Member mbr)
Member[]	expire(long maxtime)	Runs a refresh cycle and returns a list of members that has expired.
Member	getMember(Member mbr)
Member[]	getMembers()	Returning a list of all the members in the membership.
boolean	hasMembers()	Returning that service has members or not.
boolean	memberAlive(Member member)	Notify the membership that this member has announced itself.
void	removeMember(Member member)	Remove a member from this component.
void	reset()	Reset the membership and start over fresh. i.e., delete all the members and wait for them to ping again and join this membership.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

EMPTY_MEMBERS

protected static final Member[] EMPTY_MEMBERS

local

protected final Member local

The local member.

map

protected HashMap<Member,Membership.MbrEntry> map

A map of all the members in the cluster.

members

protected volatile Member[] members

A list of all the members in the cluster.

memberComparator

protected final Comparator<Member> memberComparator

Comparator for sorting members by alive time.

Constructor Details

Membership

public Membership(Member local,
 boolean includeLocal)

Constructs a new membership

Parameters:

local - - has to be the name of the local member. Used to filter the local member from the cluster membership

includeLocal - - TBA

Membership

public Membership(Member local)

Membership

public Membership(Member local,
 Comparator<Member> comp)

Membership

public Membership(Member local,
 Comparator<Member> comp,
 boolean includeLocal)

Method Details

clone

public Membership clone()

Overrides:

clone in class Object

reset

public void reset()

Reset the membership and start over fresh. i.e., delete all the members and wait for them to ping again and join this membership.

memberAlive

public boolean memberAlive(Member member)

Notify the membership that this member has announced itself.

Parameters:

member - - the member that just pinged us

Returns:

- true if this member is new to the cluster, false otherwise.
- false if this member is the local member or updated.

addMember

public Membership.MbrEntry addMember(Member member)

Add a member to this component and sort array with memberComparator

Parameters:

member - The member to add

Returns:

The member entry created for this new member.

removeMember

public void removeMember(Member member)

Remove a member from this component.

Parameters:

member - The member to remove

expire

public Member[] expire(long maxtime)

Runs a refresh cycle and returns a list of members that has expired. This also removes the members from the membership, in such a way that getMembers() = getMembers() - expire()

Parameters:

maxtime - - the max time a member can remain unannounced before it is considered dead.

Returns:

the list of expired members

hasMembers

public boolean hasMembers()

Returning that service has members or not.

Returns:

true if there are one or more members, otherwise false

getMember

public Member getMember(Member mbr)

contains

public boolean contains(Member mbr)

getMembers

public Member[] getMembers()

Returning a list of all the members in the membership. We not need a copy: add and remove generate new arrays.

Returns:

An array of the current members