infoservice.agreement.paxos.integration
Class PaxosAdapter

java.lang.Object
  infoservice.agreement.paxos.PaxosObject
      infoservice.agreement.paxos.PaxosCommunicator
          infoservice.agreement.paxos.PaxosProposer
              infoservice.agreement.paxos.PaxosAcceptor
                  infoservice.agreement.paxos.integration.PaxosAdapter

All Implemented Interfaces:

TimeoutListener

Direct Known Subclasses:

InfoServicePaxosAdapter

public abstract class PaxosAdapter
extends PaxosAcceptor

Nested Class Summary

(package private) class

PaxosAdapter.AgreementStarterThread The AgreementStarterThread looks from time to time if the next agreement has to be startet.

Field Summary

protected java.util.Hashtable	m_commitments
protected int	m_currentState
protected Commitment	m_ownCommitment
protected java.util.Vector	m_passivelyReceivedMessages
protected java.util.Vector	m_potentialyCorrectMessage
(package private) PaxosAdapter.AgreementStarterThread	m_starterThread
private static int	STATE_COMMITMENT
private static int	STATE_INACTIVE
private static int	STATE_PASSIVE
private static int	STATE_PHASE_GAP
private static int	STATE_REVEAL

Fields inherited from class infoservice.agreement.paxos.PaxosAcceptor

m_paxosInstances

Fields inherited from class infoservice.agreement.paxos.PaxosProposer

m_lastRandom

Fields inherited from class infoservice.agreement.paxos.PaxosCommunicator

m_targets

Constructor Summary

protected

PaxosAdapter() Creates a new PaxosAdapter and starts the AgreementStarterThread for starting agreement at a specific time

Method Summary

private void	babylonianConfusion() If something went terribly wrong, this gets called.
void	handleIncommingMessage(PaxosMessage a_msg) Handles an incomming message.
void	handleMessage(PaxosMessage a_msg) Handles the message by passing it to the underlying PaxosAcceptor
protected void	notifyAgreement(java.util.Hashtable a_agreements) This gets called when an agreement has been reached, i.e.
void	notifyReject(java.lang.String a_newRound) Callback for the RejectManager.
protected abstract void	prepareTargets()
protected boolean	roundNrAcceptable(PaxosMessage a_msg) Tests if the PaxosInstance-identifier in this messages is acceptable, i.e.
protected boolean	senderNotInSnapshot(PaxosMessage a_msg) Tests if the sender of this message is in the snapshot for the current PaxosInstance.
protected void	sendReject(PaxosMessage a_msg) Sends a RejectMessage to the sender of the given message.
void	startAgreement() Starts the protocol by proposing a value to the others
void	startPassivePhase() Starts the passive phase of the protocol.
void	startProtocolByOperator() Manually start an agreement
void	startRound() Starts a PaxosExection for all known IPaxosTargets so that timeouts are synchronized
protected abstract void	useAgreement(long a_agreement) What shall we do with an agreement? You can define it here

Methods inherited from class infoservice.agreement.paxos.PaxosAcceptor

addMessage, getPaxosInstance, getRoundLeaders, timeout

Methods inherited from class infoservice.agreement.paxos.PaxosProposer

propose, setRound

Methods inherited from class infoservice.agreement.paxos.PaxosCommunicator

getF, getIdentifier, getN, getQuorumDecideStrong, getQuorumDecideWeak, getQuorumStrong, getQuorumTwoThird, getTargets, multicast, sendMessage, sendMessage, setTargets

Methods inherited from class infoservice.agreement.paxos.PaxosObject

debug, error, fatal, getLog, info, setLog

Methods inherited from class java.lang.Object

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

Field Detail

STATE_INACTIVE

private static final int STATE_INACTIVE

See Also:

Constant Field Values

STATE_PASSIVE

private static final int STATE_PASSIVE

See Also:

Constant Field Values

STATE_COMMITMENT

private static final int STATE_COMMITMENT

See Also:

Constant Field Values

STATE_PHASE_GAP

private static final int STATE_PHASE_GAP

See Also:

Constant Field Values

STATE_REVEAL

private static final int STATE_REVEAL

See Also:

Constant Field Values

m_commitments

protected java.util.Hashtable m_commitments

m_ownCommitment

protected Commitment m_ownCommitment

m_passivelyReceivedMessages

protected java.util.Vector m_passivelyReceivedMessages

m_potentialyCorrectMessage

protected java.util.Vector m_potentialyCorrectMessage

m_starterThread

PaxosAdapter.AgreementStarterThread m_starterThread

m_currentState

protected int m_currentState

Constructor Detail

PaxosAdapter

protected PaxosAdapter()

Creates a new PaxosAdapter and starts the AgreementStarterThread for starting agreement at a specific time

Method Detail

prepareTargets

protected abstract void prepareTargets()

startProtocolByOperator

public void startProtocolByOperator()

Manually start an agreement

startAgreement

public void startAgreement()

Starts the protocol by proposing a value to the others

startRound

public void startRound()

Starts a PaxosExection for all known IPaxosTargets so that timeouts are synchronized

roundNrAcceptable

protected boolean roundNrAcceptable(PaxosMessage a_msg)

Tests if the PaxosInstance-identifier in this messages is acceptable, i.e. is the same as our own

Parameters:

a_msg - The message to be tested

Returns:

true if the identifier is ok, false otherwise

senderNotInSnapshot

protected boolean senderNotInSnapshot(PaxosMessage a_msg)

Tests if the sender of this message is in the snapshot for the current PaxosInstance.

Parameters:

a_msg - The message whose sender should be checked

Returns:

true if the sender is not in the snapshot, false otherwise

sendReject

protected void sendReject(PaxosMessage a_msg)

Sends a RejectMessage to the sender of the given message. This happens if the PaxosInstance-identifier of the given message doesn't match our own one

Parameters:

a_msg - The message whose sender will receive a RejectMessage

handleIncommingMessage

public void handleIncommingMessage(PaxosMessage a_msg)

Handles an incomming message. A new agreement is startet if none is running and the PaxosIdenifier of the incomming message is correct. otherwise a RejectMessage will be sent

Parameters:

a_msg - The message to be handled

handleMessage

public void handleMessage(PaxosMessage a_msg)

Handles the message by passing it to the underlying PaxosAcceptor

Parameters:

a_msg - The message to be handled

notifyReject

public void notifyReject(java.lang.String a_newRound)

Callback for the RejectManager. If this gets called, our last common random is not correct. All executions with the old identifier will be canceled and a new PaxosInstance with the correct identifier will be started

Parameters:

a_newRound -

babylonianConfusion

private void babylonianConfusion()

If something went terribly wrong, this gets called. Should never happen but who knows ;-)

notifyAgreement

protected void notifyAgreement(java.util.Hashtable a_agreements)

This gets called when an agreement has been reached, i.e. we decided on a value for all known IPaxosTargets. If the currect execution has been a commitment-phase, the corresponding reveal-phase will be started. Otherwise the agreements will be combined and new cascades will be built

Specified by:

notifyAgreement in class PaxosAcceptor

Parameters:

a_agreements - Map of execution-identifier to decission

startPassivePhase

public void startPassivePhase()

Starts the passive phase of the protocol. Incomming messages will be queued and handled when we enter the active phase

useAgreement

protected abstract void useAgreement(long a_agreement)

What shall we do with an agreement? You can define it here

Parameters:

a_agreement -