edu.umass.cs.reconfiguration.examples.noop

Class NoopAppCoordinator

java.lang.Object

edu.umass.cs.reconfiguration.AbstractReplicaCoordinator<NodeIDType>

edu.umass.cs.reconfiguration.PaxosReplicaCoordinator<java.lang.String>

edu.umass.cs.reconfiguration.examples.noop.NoopAppCoordinator

All Implemented Interfaces:

Application, AppRequestParser, AppRequestParserBytes, Replicable, Reconfigurable, ReplicaCoordinator<java.lang.String>, Repliconfigurable

public class NoopAppCoordinator
extends PaxosReplicaCoordinator<java.lang.String>

Author:

V. Arun An explicit coordinator class like this is optional and is needed only of the application wants to implement its own replica coordination scheme. For applications simply wanting to use gigapaxos as their replica coordination protocol, a class like this is unnecessary. The code below shows how to use a replica coordination scheme based on lazy propagation as an alternative to paxos. Note that the lazy propagation scheme below is not even eventually consistent and is shown here only as a trivial alternative example.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	NoopAppCoordinator.CoordType Intended to support two types of coordination policies: lazy and paxos.

Field Summary

Fields inherited from class edu.umass.cs.reconfiguration.PaxosReplicaCoordinator

log

Fields inherited from class edu.umass.cs.reconfiguration.AbstractReplicaCoordinator

app, messenger

Method Summary

Modifier and Type	Method and Description
boolean	coordinateRequest(Request request, ExecutedCallback callback) Start of abstract methods
boolean	createReplicaGroup(java.lang.String serviceName, int epoch, java.lang.String state, java.util.Set<java.lang.String> nodes) This method should return true if the replica group is successfully created or one already exists with the same set of nodes.
boolean	deleteReplicaGroup(java.lang.String serviceName, int epoch) This method should result in all state corresponding to serviceName being deleted
protected boolean	existsGroup(java.lang.String name, int epoch)
java.util.Set<java.lang.String>	getReplicaGroup(java.lang.String serviceName) This method must return the replica group that was most recently successfully created for the serviceName using createReplicaGroup.
java.util.Set<IntegerPacketType>	getRequestTypes()
ReconfigurableRequest	getStopRequest(java.lang.String name, int epoch) Returns a stop request that when executed by the app ensures that no subsequent request after the stop is executed in that epoch.

Methods inherited from class edu.umass.cs.reconfiguration.PaxosReplicaCoordinator

coordinateRequest, createReplicaGroup, deleteFinalState, existsOrHigher, forceCheckpoint, getEpoch, getFinalState, getFinalStateContainer, putInitialState, removeDead, setOutOfOrderLimit, stop, stopFailureMonitoring, toString

Methods inherited from class edu.umass.cs.reconfiguration.AbstractReplicaCoordinator

callCallback, checkpoint, execute, execute, execute, getAppRequestTypes, getARARNodesAsString, getARRCNodesAsString, getCallback, getCoordinatorRequestTypes, getMessenger, getMutualAuthAppRequestTypes, getMyID, getRequest, getRequest, getRequest, handleIncoming, hasLargeCheckpoints, registerCoordination, restore, sendAllLazy, setCallback, setLargeCheckpoints, setMessenger, setStopCallback

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.umass.cs.gigapaxos.interfaces.AppRequestParser

getMutualAuthRequestTypes, getServerAuthRequestTypes

Method Detail

coordinateRequest

public boolean coordinateRequest(Request request,
                                 ExecutedCallback callback)
                          throws java.io.IOException,
                                 RequestParseException

Description copied from class: AbstractReplicaCoordinator

Start of abstract methods

Specified by:

coordinateRequest in interface ReplicaCoordinator<java.lang.String>

Overrides:

coordinateRequest in class PaxosReplicaCoordinator<java.lang.String>

Returns:

Success of coordination.

Throws:

java.io.IOException

RequestParseException

createReplicaGroup

public boolean createReplicaGroup(java.lang.String serviceName,
                                  int epoch,
                                  java.lang.String state,
                                  java.util.Set<java.lang.String> nodes)

Description copied from interface: ReplicaCoordinator

This method should return true if the replica group is successfully created or one already exists with the same set of nodes. It should return false otherwise.

Specified by:

createReplicaGroup in interface ReplicaCoordinator<java.lang.String>

Overrides:

createReplicaGroup in class PaxosReplicaCoordinator<java.lang.String>

Returns:

True if created successfully.

deleteReplicaGroup

public boolean deleteReplicaGroup(java.lang.String serviceName,
                                  int epoch)

Description copied from interface: ReplicaCoordinator

This method should result in all state corresponding to serviceName being deleted

Specified by:

deleteReplicaGroup in interface ReplicaCoordinator<java.lang.String>

Overrides:

deleteReplicaGroup in class PaxosReplicaCoordinator<java.lang.String>

Returns:

True if deleted without errors.

getReplicaGroup

public java.util.Set<java.lang.String> getReplicaGroup(java.lang.String serviceName)

Description copied from interface: ReplicaCoordinator

This method must return the replica group that was most recently successfully created for the serviceName using createReplicaGroup.

Specified by:

getReplicaGroup in interface ReplicaCoordinator<java.lang.String>

Overrides:

getReplicaGroup in class PaxosReplicaCoordinator<java.lang.String>

Returns:

Set of nodes in the replica group for serviceName.

getRequestTypes

public java.util.Set<IntegerPacketType> getRequestTypes()

Specified by:

getRequestTypes in interface AppRequestParser

Overrides:

getRequestTypes in class PaxosReplicaCoordinator<java.lang.String>

Returns:

The set of request types that the application expects to process.

getStopRequest

public ReconfigurableRequest getStopRequest(java.lang.String name,
                                            int epoch)

Description copied from interface: Reconfigurable

Returns a stop request that when executed by the app ensures that no subsequent request after the stop is executed in that epoch. We need the app to return a stop request as opposed to just exposing a stop() method because, in general, the stop may need to be coordinated across app replicas. If nothing special has to be done by the app upon an epoch stop, it is okay for this method to just return null or a no-op request. If an app is using PaxosReplicaCoordinator, nothing special needs to be done by the app upon an epoch stop, so it can return either null or a no-op request.

Specified by:

getStopRequest in interface Reconfigurable

Overrides:

getStopRequest in class PaxosReplicaCoordinator<java.lang.String>

Returns:

InterfaceReconfigurableRequest corresponding to the stop request for the replica group name:epoch.

existsGroup

protected boolean existsGroup(java.lang.String name,
                              int epoch)