edu.umass.cs.reconfiguration.reconfigurationprotocoltasks

Class WaitAckDropEpoch<NodeIDType>

java.lang.Object

edu.umass.cs.protocoltask.ThresholdProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>

edu.umass.cs.reconfiguration.reconfigurationprotocoltasks.WaitAckDropEpoch<NodeIDType>

Type Parameters:

NodeIDType -

All Implemented Interfaces:

ProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>, SchedulableProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>, Keyable<java.lang.String>

public class WaitAckDropEpoch<NodeIDType>
extends ThresholdProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>

Author:

V. Arun

Field Summary

Fields

Modifier and Type	Field and Description
static ReconfigurationPacket.PacketType[]	types Packet types handled.

Fields inherited from class edu.umass.cs.protocoltask.ThresholdProtocolTask

waitfor

Constructor Summary

Constructors

Constructor and Description
WaitAckDropEpoch(StartEpoch<NodeIDType> startEpoch, RepliconfigurableReconfiguratorDB<NodeIDType> DB)
WaitAckDropEpoch(StartEpoch<NodeIDType> startEpoch, java.util.Set<NodeIDType> prevGroup, RepliconfigurableReconfiguratorDB<NodeIDType> DB)

Method Summary

Modifier and Type	Method and Description
java.util.Set<ReconfigurationPacket.PacketType>	getEventTypes()
java.lang.String	getKey()
boolean	handleEvent(ProtocolEvent<ReconfigurationPacket.PacketType,java.lang.String> event)
GenericMessagingTask<NodeIDType,?>[]	handleThresholdEvent(ProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>[] ptasks) We should delete the record currently pending deletion.
java.lang.String	refreshKey()
GenericMessagingTask<NodeIDType,?>[]	restart()
GenericMessagingTask<NodeIDType,?>[]	start() We skip the first period before sending out drop epochs.

Methods inherited from class edu.umass.cs.protocoltask.ThresholdProtocolTask

fix, getPeriod, handleEvent, setPeriod

Methods inherited from class java.lang.Object

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

Field Detail

types

public static final ReconfigurationPacket.PacketType[] types

Packet types handled.

Constructor Detail

WaitAckDropEpoch

public WaitAckDropEpoch(StartEpoch<NodeIDType> startEpoch,
                        java.util.Set<NodeIDType> prevGroup,
                        RepliconfigurableReconfiguratorDB<NodeIDType> DB)

Parameters:

startEpoch -

prevGroup -

DB - The getAllActive() call is a hack to be able to finish deletes quicker. This has safety violation risks upon name re-creation and is meant only for instrumentation.

WaitAckDropEpoch

public WaitAckDropEpoch(StartEpoch<NodeIDType> startEpoch,
                        RepliconfigurableReconfiguratorDB<NodeIDType> DB)

Parameters:

startEpoch -

DB -

Method Detail

restart

public GenericMessagingTask<NodeIDType,?>[] restart()

Returns:

The messaging task upon each restart.

start

public GenericMessagingTask<NodeIDType,?>[] start()

We skip the first period before sending out drop epochs. It is good to delay it a bit as some replicas may still not be done acquiring the previous epoch final state and it is good for them to have the opportunity to do so from a previous epoch replica rather than a paxos peer replica in the new epoch. This delaying is not needed for safety as a majority of replicas must have already started the new epoch by the time a drop epoch task is spawned, so this (minority) replica can always get the current state through a checkpoint transfer from one of the majority peer replica in the new epoch in case all previous epoch final state has been garbage collected before it could start the new epoch.

Returns:

Initial messaging task.

refreshKey

public java.lang.String refreshKey()

Returns:

The refreshed key.

getEventTypes

public java.util.Set<ReconfigurationPacket.PacketType> getEventTypes()

Returns:

The event types processed by this protocol task.

getKey

public java.lang.String getKey()

Returns:

The key.

handleEvent

public boolean handleEvent(ProtocolEvent<ReconfigurationPacket.PacketType,java.lang.String> event)

Specified by:

handleEvent in class ThresholdProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>

Returns:

Return value indicates if the event is a valid response.

handleThresholdEvent

public GenericMessagingTask<NodeIDType,?>[] handleThresholdEvent(ProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>[] ptasks)

We should delete the record currently pending deletion.

Overrides:

handleThresholdEvent in class ThresholdProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>

Returns:

Returns messaging tasks to be performed when the threshold is reached. Additional protocol task actions may also be spawned via ptasks[0].