infoservice.agreement.paxos
Class PaxosCommunicator

java.lang.Object
  infoservice.agreement.paxos.PaxosObject
      infoservice.agreement.paxos.PaxosCommunicator

Direct Known Subclasses:

PaxosProposer

public abstract class PaxosCommunicator
extends PaxosObject

Field Summary

protected java.util.Hashtable

m_targets

Constructor Summary

PaxosCommunicator()

Method Summary

protected int	getF() Returns f, the number of maximum tolerable faulty processes
protected abstract java.lang.String	getIdentifier() Returns the unique identifier for this PaxosCommunicator
int	getN() Returns n, the number of all known processes
protected int	getQuorumDecideStrong() Returns the quorum needed to decide if a proposal has been strong-accepted (2f)
protected int	getQuorumDecideWeak() Gets the quorum needed to fast decide (n+3f)/2
protected int	getQuorumStrong() Returns the quorum needed to strong-accept a value: (n+f)/2
int	getQuorumTwoThird()
java.util.Hashtable	getTargets() Returns the Hashtable of all known targets
void	multicast(PaxosMessage a_msg) Multicasts the given message to all known IPaxosTargets.
private int	nextLower(double a_roof) Returns the next lower integer for the given double
private int	nextUpper(double a_bottom) Returns the next larger integer to the given double
abstract void	sendMessage(PaxosMessage a_msg, IPaxosTarget a_target) Sends the given message to the given target.
void	sendMessage(java.lang.String a_id, PaxosMessage a_msg) Sends the given message to the IPaxosTarget with the given ID
void	setTargets(java.util.Hashtable a_targets) Sets the targets, i.e.

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

m_targets

protected java.util.Hashtable m_targets

Constructor Detail

PaxosCommunicator

public PaxosCommunicator()

Method Detail

multicast

public void multicast(PaxosMessage a_msg)

Multicasts the given message to all known IPaxosTargets. Uses sendMessage

Parameters:

a_msg - The message to multicast

sendMessage

public void sendMessage(java.lang.String a_id,
                        PaxosMessage a_msg)

Sends the given message to the IPaxosTarget with the given ID

Parameters:

a_id - The ID of the IPaxosTarget to which to send

a_msg - The message to send

getTargets

public java.util.Hashtable getTargets()

Returns the Hashtable of all known targets

Returns:

The Hashtable of all known targets

getQuorumStrong

protected int getQuorumStrong()

Returns the quorum needed to strong-accept a value: (n+f)/2

Returns:

The quorum needed to strong-accept a value: (n+f)/2

getQuorumDecideWeak

protected int getQuorumDecideWeak()

Gets the quorum needed to fast decide (n+3f)/2

Returns:

The quorum needed to fast decide (n+3f)/2

getQuorumDecideStrong

protected int getQuorumDecideStrong()

Returns the quorum needed to decide if a proposal has been strong-accepted (2f)

Returns:

The quorum needed to decide if a proposal has been strong-accepted (2f)

getF

protected int getF()

Returns f, the number of maximum tolerable faulty processes

Returns:

f, the number of maximum tolerable faulty processes

getN

public int getN()

Returns n, the number of all known processes

Returns:

getQuorumTwoThird

public int getQuorumTwoThird()

setTargets

public void setTargets(java.util.Hashtable a_targets)

Sets the targets, i.e. known other participants

Parameters:

a_targets - A Vector containing IPaxosTargets

nextUpper

private int nextUpper(double a_bottom)

Returns the next larger integer to the given double

Parameters:

a_bottom -

Returns:

nextLower

private int nextLower(double a_roof)

Returns the next lower integer for the given double

Parameters:

a_roof - The double

Returns:

The next lower integer

sendMessage

public abstract void sendMessage(PaxosMessage a_msg,
                                 IPaxosTarget a_target)

Sends the given message to the given target.

Parameters:

a_msg -

a_target -

getIdentifier

protected abstract java.lang.String getIdentifier()

Returns the unique identifier for this PaxosCommunicator

Returns:

The unique identifier for this PaxosCommunicator