org.universAAL.middleware.ui.impl.generic

Class CoordinatedStrategy

java.lang.Object

java.lang.Thread

org.universAAL.middleware.bus.model.BusStrategy

org.universAAL.middleware.ui.impl.generic.EventBasedStrategy

org.universAAL.middleware.ui.impl.generic.CallBasedStrategy

org.universAAL.middleware.ui.impl.generic.CoordinatedStrategy

All Implemented Interfaces:

Runnable, SharedObjectListener, SpaceListener

Direct Known Subclasses:

CoordinatedRegistrationManagement

public class CoordinatedStrategy
extends CallBasedStrategy
implements SpaceListener, SharedObjectListener

Strategy stack dedicated only to manage Coordination of the bus.
This strategy consists of 3 basic events:

1. Coordinator_Broadcast : used to announce coordinator and respond to coordinator requests
2. Coordinator_Request: used to request a coordinator when there is not one yet
3. Coordinator_Resign: used by the coordinator instance to resign from being a coordinator.

The strategy subscribes to the SpaceManager to listen to lost peers, in case they are the coordinator; or if the Coordinator has left the coordinated space, it automatically surrenders coordination. Also new Peers joining the space will proactively be informed about who is the coordinator.

Author:

amedrano

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CoordinatedStrategy.CoordinatorAlreadyExistsException Exception indicating there is already a Coordinator.

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields

Modifier and Type	Field and Description
static String	TYPE_UI_BUS_COORDINATOR_BROADCAST
static String	TYPE_UI_BUS_COORDINATOR_REQUEST
static String	TYPE_UI_BUS_COORDINATOR_RESIGN

Fields inherited from class org.universAAL.middleware.bus.model.BusStrategy

bus, busModule, commModule

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor and Description
CoordinatedStrategy(CommunicationModule commModule)
CoordinatedStrategy(CommunicationModule commModule, String name)

Method Summary

Modifier and Type	Method and Description
void	close() Tearing down
PeerCard	getCoordinator()
protected boolean	iAmCoordinator()
protected void	lostCoordinator() Extending classes may override this method to perform any opertation needed when the coordinator is lost.
void	peerJoined(PeerCard peer)
void	peerLost(PeerCard peer)
protected void	requestBecomeACoordinator() Check the conditions and announce this Peer as coordinator.
protected void	resignFromCoordinator() Check and announce this Peer is no longer the coordinator.
void	sharedObjectAdded(Object sharedObj, Object removeHook)
void	sharedObjectRemoved(Object removeHook)
void	spaceJoined(SpaceDescriptor spaceDescriptor)
void	spaceLost(SpaceDescriptor spaceDescriptor)
void	spaceStatusChanged(SpaceStatus status)
void	start()

Methods inherited from class org.universAAL.middleware.ui.impl.generic.CallBasedStrategy

abortAll, abortCall, handle, placeAsynchronousRequest, placeAsynchronousRequest, placeSynchronousRequest, placeSynchronousRequest, sendAsynchronousResponse, sendAsynchronousResponse, sendSynchronousResponse

Methods inherited from class org.universAAL.middleware.ui.impl.generic.EventBasedStrategy

sendEventToRemoteBusMember, sendEventToRemoteBusMember, sendEventToRemoteBusMember, sendEventToRemoteBusMember, sendEventToRemoteBusMember

Methods inherited from class org.universAAL.middleware.bus.model.BusStrategy

buildChannelMessage, getBusMember, getLocalBusByName, handleMessage, run, send, setBus, stopThread

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

TYPE_UI_BUS_COORDINATOR_BROADCAST

public static final String TYPE_UI_BUS_COORDINATOR_BROADCAST

See Also:

Constant Field Values

TYPE_UI_BUS_COORDINATOR_REQUEST

public static final String TYPE_UI_BUS_COORDINATOR_REQUEST

See Also:

Constant Field Values

TYPE_UI_BUS_COORDINATOR_RESIGN

public static final String TYPE_UI_BUS_COORDINATOR_RESIGN

See Also:

Constant Field Values

Constructor Detail

CoordinatedStrategy

public CoordinatedStrategy(CommunicationModule commModule)

Parameters:

commModule -

CoordinatedStrategy

public CoordinatedStrategy(CommunicationModule commModule,
                           String name)

Parameters:

commModule -

name -

Method Detail

lostCoordinator

protected void lostCoordinator()

Extending classes may override this method to perform any opertation needed when the coordinator is lost.

start

public void start()

Overrides:

start in class Thread

iAmCoordinator

protected final boolean iAmCoordinator()

requestBecomeACoordinator

protected final void requestBecomeACoordinator()
                                        throws CoordinatedStrategy.CoordinatorAlreadyExistsException

Check the conditions and announce this Peer as coordinator.

Throws:

CoordinatedStrategy.CoordinatorAlreadyExistsException

resignFromCoordinator

protected final void resignFromCoordinator()
                                    throws CoordinatedStrategy.CoordinatorAlreadyExistsException

Check and announce this Peer is no longer the coordinator.

Throws:

CoordinatedStrategy.CoordinatorAlreadyExistsException - in case this peer is not the coordinator.

getCoordinator

public final PeerCard getCoordinator()

spaceJoined

public void spaceJoined(SpaceDescriptor spaceDescriptor)

Specified by:

spaceJoined in interface SpaceListener

Parameters:

spaceDescriptor - Space desce

spaceLost

public void spaceLost(SpaceDescriptor spaceDescriptor)

Specified by:

spaceLost in interface SpaceListener

Parameters:

spaceDescriptor - Space descriptor

peerJoined

public void peerJoined(PeerCard peer)

Specified by:

peerJoined in interface SpaceListener

Parameters:

peer - PeerCard

peerLost

public void peerLost(PeerCard peer)

Specified by:

peerLost in interface SpaceListener

spaceStatusChanged

public void spaceStatusChanged(SpaceStatus status)

Specified by:

spaceStatusChanged in interface SpaceListener

sharedObjectAdded

public void sharedObjectAdded(Object sharedObj,
                              Object removeHook)

Specified by:

sharedObjectAdded in interface SharedObjectListener

sharedObjectRemoved

public void sharedObjectRemoved(Object removeHook)

Specified by:

sharedObjectRemoved in interface SharedObjectListener

close

public void close()

Tearing down