org.apache.zookeeper.server.quorum
Class Leader

java.lang.Object
  org.apache.zookeeper.server.quorum.Leader

public class Leader
extends Object

This class has the control logic for the Leader.

Nested Class Summary

static class	Leader.Proposal
static class	Leader.XidRolloverException

Field Summary

HashSet<LearnerHandler>	forwardingFollowers
HashSet<LearnerHandler>	learners
protected HashSet<LearnerHandler>	observingLearners
HashMap<Long,List<LearnerSyncRequest>>	pendingSyncs
static int	PROPOSAL This message type is sent by a leader to propose a mutation.

Method Summary

void	commit(long zxid) Create a commit packet and send it to all the members of the quorum
long	getEpoch() Returns the current epoch of the leader.
void	inform(Leader.Proposal proposal) Create an inform packet and send it to all observers.
void	processAck(long sid, long zxid, SocketAddress followerAddr) Keep a count of acks that are received by the leader for a particular proposal
void	processSync(LearnerSyncRequest r) Process sync requests
Leader.Proposal	propose(Request request) create a proposal and send it out to all the members
void	sendSync(LearnerSyncRequest r) Sends a sync message to the appropriate server
long	startForwarding(LearnerHandler handler, long lastSeenZxid) lets the leader know that a follower is capable of following and is done syncing

Methods inherited from class java.lang.Object

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

Field Detail

learners

public final HashSet<LearnerHandler> learners

forwardingFollowers

public final HashSet<LearnerHandler> forwardingFollowers

observingLearners

protected final HashSet<LearnerHandler> observingLearners

pendingSyncs

public final HashMap<Long,List<LearnerSyncRequest>> pendingSyncs

PROPOSAL

public static final int PROPOSAL

This message type is sent by a leader to propose a mutation.

See Also:

Constant Field Values

Method Detail

processAck

public void processAck(long sid,
                       long zxid,
                       SocketAddress followerAddr)

Keep a count of acks that are received by the leader for a particular proposal

Parameters:

zxid - the zxid of the proposal sent out

followerAddr -

commit

public void commit(long zxid)

Create a commit packet and send it to all the members of the quorum

Parameters:

zxid -

inform

public void inform(Leader.Proposal proposal)

Create an inform packet and send it to all observers.

Parameters:

zxid -

proposal -

getEpoch

public long getEpoch()

Returns the current epoch of the leader.

Returns:

propose

public Leader.Proposal propose(Request request)
                        throws Leader.XidRolloverException

create a proposal and send it out to all the members

Parameters:

request -

Returns:

the proposal that is queued to send to all the members

Throws:

Leader.XidRolloverException

processSync

public void processSync(LearnerSyncRequest r)

Process sync requests

Parameters:

r - the request

sendSync

public void sendSync(LearnerSyncRequest r)

Sends a sync message to the appropriate server

Parameters:

f -

r -

startForwarding

public long startForwarding(LearnerHandler handler,
                            long lastSeenZxid)

lets the leader know that a follower is capable of following and is done syncing

Parameters:

handler - handler of the follower

Returns:

last proposed zxid