edu.umass.cs.reconfiguration

Class ActiveReplica<NodeIDType>

java.lang.Object

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

Type Parameters:

NodeIDType - This class is the main wrapper around active replicas of reconfigurable app instances. It processes requests both from the Reconfigurator as well as the underlying app's clients. This class is also use to wrap the Reconfigurator itself in order to reconfigure Reconfigurators (to correctly perform reconfigurator add/remove operations).

This class handles the following ReconfigurationPackets: STOP_EPOCH, START_EPOCH, REQUEST_EPOCH_FINAL_STATE, DROP_EPOCH as also listed in ActiveReplicaProtocolTask. It relies upon the app's implementation of AbstractDemandProfile in order to determine how frequenltly to report demand statistics to Reconfigurators and whether and how to reconfigure the current active replica placement.

All Implemented Interfaces:

ExecutedCallback, PacketDemultiplexer<Request>, ReconfiguratorCallback

public class ActiveReplica<NodeIDType>
extends java.lang.Object
implements ReconfiguratorCallback, PacketDemultiplexer<Request>

Author:

V. Arun

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ActiveReplica(AbstractReplicaCoordinator<NodeIDType> appC, ReconfigurableNodeConfig<NodeIDType> nodeConfig, SSLMessenger<NodeIDType,?> messenger)

Method Summary

Modifier and Type	Method and Description
void	close() For graceful closure.
void	executed(Request request, boolean handled)
static int	getClientFacingClearPort(int port)
static int	getClientFacingPort(int port)
static int	getClientFacingSSLPort(int port)
protected java.util.Set<IntegerPacketType>	getPacketTypes()
protected java.util.Set<IntegerPacketType>	getPacketTypes(boolean allow)
GenericMessagingTask<NodeIDType,?>[]	handleDropEpochFinalState(DropEpochFinalState<NodeIDType> event, ProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>[] ptasks)
GenericMessagingTask<NodeIDType,?>[]	handleEchoRequest(EchoRequest echo, ProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>[] ptasks)
boolean	handleMessage(Request incoming, NIOHeader header)
GenericMessagingTask<NodeIDType,?>[]	handleRequestEpochFinalState(RequestEpochFinalState<NodeIDType> event, ProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>[] ptasks)
GenericMessagingTask<NodeIDType,?>[]	handleStartEpoch(StartEpoch<NodeIDType> event, ProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>[] ptasks) Will spawn FetchEpochFinalState to fetch the final state of the previous epoch if one existed, else will locally create the current epoch with an empty initial state.
GenericMessagingTask<NodeIDType,?>[]	handleStopEpoch(StopEpoch<NodeIDType> stopEpoch, ProtocolTask<NodeIDType,ReconfigurationPacket.PacketType,java.lang.String>[] ptasks)
protected void	initInstrumenter()
java.lang.String	preCheckpoint(java.lang.String name)
boolean	preExecuted(Request request)
boolean	preRestore(java.lang.String name, java.lang.String state)
java.lang.String	toString()
protected static AbstractReplicaCoordinator<?>	wrapCoordinator(AbstractReplicaCoordinator<?> coordinator)

Methods inherited from class java.lang.Object

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

Constructor Detail

ActiveReplica

protected ActiveReplica(AbstractReplicaCoordinator<NodeIDType> appC,
                        ReconfigurableNodeConfig<NodeIDType> nodeConfig,
                        SSLMessenger<NodeIDType,?> messenger)

Method Detail

wrapCoordinator

protected static AbstractReplicaCoordinator<?> wrapCoordinator(AbstractReplicaCoordinator<?> coordinator)

preCheckpoint

public java.lang.String preCheckpoint(java.lang.String name)

Specified by:

preCheckpoint in interface ReconfiguratorCallback

Parameters:

name -

Returns:

Refer Replicable.checkpoint(String).

preRestore

public boolean preRestore(java.lang.String name,
                          java.lang.String state)

Specified by:

preRestore in interface ReconfiguratorCallback

Returns:

True if app's restore method doesn't have to be called.

initInstrumenter

protected void initInstrumenter()

handleMessage

public boolean handleMessage(Request incoming,
                             NIOHeader header)

Specified by:

handleMessage in interface PacketDemultiplexer<Request>

Returns:

The return value should return true if the handler handled the message and doesn't want any other BasicPacketDemultiplexer to handle the message.

executed

public void executed(Request request,
                     boolean handled)

Specified by:

executed in interface ExecutedCallback

getPacketTypes

protected java.util.Set<IntegerPacketType> getPacketTypes(boolean allow)

Returns:

Set of packet types processed by ActiveReplica on the server port. These include active replica types plus app or app coordinator types allowed on the server port.

getPacketTypes

protected java.util.Set<IntegerPacketType> getPacketTypes()

close

public void close()

For graceful closure.

handleStartEpoch

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

Will spawn FetchEpochFinalState to fetch the final state of the previous epoch if one existed, else will locally create the current epoch with an empty initial state.

Parameters:

event -

ptasks -

Returns:

Messaging task, typically null as we spawn a protocol task to fetch the previous epoch's final state.

handleStopEpoch

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

Parameters:

stopEpoch -

ptasks -

Returns:

Messaging task, typically null as we coordinate the stop request and use a callback to notify the reconfigurator that issued the StopEpoch.

handleDropEpochFinalState

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

Parameters:

event -

ptasks -

Returns:

Messaging task to send AckDropEpochFinalState to reconfigurator that issued the corresponding DropEpochFinalState.

handleEchoRequest

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

Parameters:

echo -

ptasks -

Returns:

null

handleRequestEpochFinalState

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

Parameters:

event -

ptasks -

Returns:

Messaging task returning the requested epoch final state to the requesting ActiveReplica.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getClientFacingPort

public static final int getClientFacingPort(int port)

Parameters:

port -

Returns:

The client facing port number corresponding to port.

getClientFacingClearPort

public static final int getClientFacingClearPort(int port)

Parameters:

port -

Returns:

The client facing clear port corresponding to port.

getClientFacingSSLPort

public static final int getClientFacingSSLPort(int port)

Parameters:

port -

Returns:

The client facing ssl port number corresponding to port.

preExecuted

public boolean preExecuted(Request request)

Specified by:

preExecuted in interface ReconfiguratorCallback

Returns:

True if execution complete.