org.atmosphere.cpr
Class DefaultBroadcaster

java.lang.Object
  org.atmosphere.cpr.DefaultBroadcaster

All Implemented Interfaces:

Broadcaster

Direct Known Subclasses:

AbstractBroadcasterProxy, ExcludeSessionBroadcaster, SimpleBroadcaster

public class DefaultBroadcaster
extends Object
implements Broadcaster

The default Broadcaster implementation.

Broadcast messages to suspended responses using the caller's Thread. This basic Broadcaster use an ExecutorService to broadcast messages, hence the broadcast operation is asynchronous. Make sure you block on broadcast(Object).get()} if you need synchronous operations.

Author:

Jeanfrancois Arcand

Nested Class Summary

protected static class

DefaultBroadcaster.AsyncWriteToken

Nested classes/interfaces inherited from interface org.atmosphere.cpr.Broadcaster

Broadcaster.POLICY, Broadcaster.SCOPE

Field Summary

static String	ASYNC_TOKEN
protected Future<?>[]	asyncWriteFuture
protected BroadcasterConfig	bc
protected ConcurrentLinkedQueue<BroadcasterListener>	broadcasterListeners
protected ConcurrentLinkedQueue<Entry>	broadcastOnResume
static String	CACHED
protected AtmosphereConfig	config
protected ConcurrentLinkedQueue<Entry>	delayedBroadcast
protected AtomicBoolean	destroyed
protected AtomicInteger	dispatchThread
protected ConcurrentLinkedQueue<BroadcasterLifeCyclePolicyListener>	lifeCycleListeners
protected BlockingQueue<Entry>	messages
protected String	name
protected AtmosphereResource	noOpsResource
protected Future<?>[]	notifierFuture
static int	POLLING_DEFAULT
protected ConcurrentLinkedQueue<AtmosphereResource>	resources
protected Broadcaster.SCOPE	scope
protected AtomicBoolean	started
protected org.atmosphere.cpr.DefaultBroadcaster.WriteQueue	uniqueWriteQueue
protected URI	uri
protected int	waitTime
protected ConcurrentHashMap<String,org.atmosphere.cpr.DefaultBroadcaster.WriteQueue>	writeQueues
protected int	writeTimeoutInSecond

Constructor Summary

DefaultBroadcaster(String name, AtmosphereConfig config)

DefaultBroadcaster(String name, URI uri, AtmosphereConfig config)

Method Summary

Broadcaster	addAtmosphereResource(AtmosphereResource r) Add a AtmosphereResource to the list of items to be notified when the Broadcaster.broadcast(java.lang.Object) is invoked.
void	addBroadcasterLifeCyclePolicyListener(BroadcasterLifeCyclePolicyListener b) Add a BroadcasterLifeCyclePolicyListener.
Broadcaster	addBroadcasterListener(BroadcasterListener b) Add a BroadcasterListener.
Future<Object>	awaitAndBroadcast(Object t, long time, TimeUnit timeUnit) Await for available AtmosphereResource before broadcasting.
Future<Object>	broadcast(Object msg) Broadcast the Object to all suspended responses, eg.
Future<Object>	broadcast(Object msg, AtmosphereResource r) Broadcast the Object to all suspended responses, eg.
Future<Object>	broadcast(Object msg, Set<AtmosphereResource> subset) Broadcast the Object to all suspended response, eg.
protected void	broadcastOnResume(AtmosphereResource r)
Future<Object>	broadcastOnResume(Object msg) Broadcast the Object when an AtmosphereResource is resumed by a timeout or when using AtmosphereResource.resume().
protected void	cacheAndSuspend(AtmosphereResource r) Look in the cache to see if there are messages available, and take the appropriate actions.
void	cacheLostMessage(AtmosphereResource r) Cache the message because an unexpected exception occurred.
void	cacheLostMessage(AtmosphereResource r, boolean force) Cache the message because an unexpected exception occurred.
void	cacheLostMessage(AtmosphereResource r, DefaultBroadcaster.AsyncWriteToken token) Cache the message because an unexpected exception occurred.
void	cacheLostMessage(AtmosphereResource r, DefaultBroadcaster.AsyncWriteToken token, boolean force) Cache the message because an unexpected exception occurred.
protected boolean	checkCachedAndPush(AtmosphereResource r, AtmosphereResourceEvent e)
protected BroadcasterConfig	createBroadcasterConfig(AtmosphereConfig config) Create BroadcasterConfig.
Future<Object>	delayBroadcast(Object o) Delay the broadcast operation.
Future<Object>	delayBroadcast(Object o, long delay, TimeUnit t) Delay the broadcast operation.
protected void	deliverPush(Entry entry, boolean rec)
void	destroy() Destroy this instance and shutdown it's associated ExecutorService.
protected void	dispatchMessages(Entry e)
protected void	entryDone(BroadcasterFuture<?> f)
protected void	executeAsyncWrite(DefaultBroadcaster.AsyncWriteToken token)
protected void	executeBlockingWrite(AtmosphereResource r, Entry entry)
protected Object	filter(Object msg) Invoke the BroadcastFilter
protected BroadcasterFuture<Object>	futureDone(Object msg)
protected Runnable	getAsyncWriteHandler(org.atmosphere.cpr.DefaultBroadcaster.WriteQueue writeQueue)
Collection<AtmosphereResource>	getAtmosphereResources() Return an List of AtmosphereResource.
BroadcasterConfig	getBroadcasterConfig() Return the current BroadcasterConfig.
protected Runnable	getBroadcastHandler()
String	getID() Return the ID of this Broadcaster.
Broadcaster.SCOPE	getScope() Return the Broadcaster.SCOPE.
protected void	invokeOnStateChange(AtmosphereResource r, AtmosphereResourceEvent e)
boolean	isDestroyed() Return true if this Broadcaster has been destroyed.
protected void	killReactiveThreads()
protected void	notifyAndAdd(AtmosphereResource r)
protected void	notifyBroadcastListener()
protected void	notifyDestroyListener()
protected void	notifyEmptyListener()
protected void	notifyIdleListener()
protected void	notifyOnAddAtmosphereResourceListener(AtmosphereResource r)
protected void	notifyOnRemoveAtmosphereResourceListener(AtmosphereResource r)
void	onException(Throwable t, AtmosphereResource ar)
void	onException(Throwable t, AtmosphereResource ar, boolean notifyAndCache)
protected boolean	perRequestFilter(AtmosphereResource r, Entry msg)
protected void	prepareInvokeOnStateChange(AtmosphereResource r, AtmosphereResourceEvent e)
protected void	push(Entry entry)
protected void	queueWriteIO(AtmosphereResource r, Entry entry)
protected int	reactiveThreadsCount() Return the default number of reactive threads that will be waiting for work when a broadcast operation is executed.
void	releaseExternalResources() Release external resources associated with this Broadcaster.
Broadcaster	removeAtmosphereResource(AtmosphereResource r) Remove a AtmosphereResource from the list of s to be notified when the Broadcaster.broadcast(java.lang.Object) is invoked.
protected Broadcaster	removeAtmosphereResource(AtmosphereResource r, boolean executeDone)
void	removeBroadcasterLifeCyclePolicyListener(BroadcasterLifeCyclePolicyListener b) Remove a BroadcasterLifeCyclePolicyListener.
Broadcaster	removeBroadcasterListener(BroadcasterListener b) Remove a BroadcasterListener.
void	resumeAll() Resume all suspended responses (AtmosphereResource) added via Broadcaster.addAtmosphereResource(org.atmosphere.cpr.AtmosphereResource).
protected boolean	retrieveTrackedBroadcast(AtmosphereResource r, AtmosphereResourceEvent e)
Future<Object>	scheduleFixedBroadcast(Object o, long waitFor, long period, TimeUnit t) Broadcast periodically.
Future<Object>	scheduleFixedBroadcast(Object o, long period, TimeUnit t) Broadcast periodically.
void	setBroadcasterConfig(BroadcasterConfig bc) Set the BroadcasterConfig instance.
void	setBroadcasterLifeCyclePolicy(BroadcasterLifeCyclePolicy lifeCyclePolicy) Set the BroadcasterLifeCyclePolicy.
void	setID(String id) Set the ID of this Broadcaster.
void	setScope(Broadcaster.SCOPE scope) Set the scope.
void	setSuspendPolicy(long maxSuspendResource, Broadcaster.POLICY policy) Set the maximum number of suspended AtmosphereResources.
protected void	spawnReactor()
protected void	start()
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

POLLING_DEFAULT

public static final int POLLING_DEFAULT

See Also:

Constant Field Values

CACHED

public static final String CACHED

ASYNC_TOKEN

public static final String ASYNC_TOKEN

resources

protected final ConcurrentLinkedQueue<AtmosphereResource> resources

bc

protected BroadcasterConfig bc

messages

protected final BlockingQueue<Entry> messages

broadcasterListeners

protected final ConcurrentLinkedQueue<BroadcasterListener> broadcasterListeners

started

protected final AtomicBoolean started

destroyed

protected final AtomicBoolean destroyed

scope

protected Broadcaster.SCOPE scope

name

protected String name

delayedBroadcast

protected final ConcurrentLinkedQueue<Entry> delayedBroadcast

broadcastOnResume

protected final ConcurrentLinkedQueue<Entry> broadcastOnResume

lifeCycleListeners

protected final ConcurrentLinkedQueue<BroadcasterLifeCyclePolicyListener> lifeCycleListeners

writeQueues

protected final ConcurrentHashMap<String,org.atmosphere.cpr.DefaultBroadcaster.WriteQueue> writeQueues

uniqueWriteQueue

protected final org.atmosphere.cpr.DefaultBroadcaster.WriteQueue uniqueWriteQueue

dispatchThread

protected final AtomicInteger dispatchThread

notifierFuture

protected Future<?>[] notifierFuture

asyncWriteFuture

protected Future<?>[] asyncWriteFuture

uri

protected URI uri

config

protected AtmosphereConfig config

writeTimeoutInSecond

protected int writeTimeoutInSecond

noOpsResource

protected final AtmosphereResource noOpsResource

waitTime

protected int waitTime

Constructor Detail

DefaultBroadcaster

public DefaultBroadcaster(String name,
                          URI uri,
                          AtmosphereConfig config)

DefaultBroadcaster

public DefaultBroadcaster(String name,
                          AtmosphereConfig config)

Method Detail

createBroadcasterConfig

protected BroadcasterConfig createBroadcasterConfig(AtmosphereConfig config)

Create BroadcasterConfig.

Parameters:

config - the AtmosphereConfig

Returns:

an instance of BroadcasterConfig

destroy

public void destroy()

Description copied from interface: Broadcaster

Destroy this instance and shutdown it's associated ExecutorService.

Specified by:

destroy in interface Broadcaster

getAtmosphereResources

public Collection<AtmosphereResource> getAtmosphereResources()

Description copied from interface: Broadcaster

Return an List of AtmosphereResource.

Specified by:

getAtmosphereResources in interface Broadcaster

Returns:

List of AtmosphereResource associated with this Broadcaster.

See Also:

Broadcaster.addAtmosphereResource(AtmosphereResource)

setScope

public void setScope(Broadcaster.SCOPE scope)

Description copied from interface: Broadcaster

Set the scope.

Specified by:

setScope in interface Broadcaster

Parameters:

scope - Broadcaster.SCOPE to set.

getScope

public Broadcaster.SCOPE getScope()

Description copied from interface: Broadcaster

Return the Broadcaster.SCOPE.

Specified by:

getScope in interface Broadcaster

Returns:

Broadcaster.SCOPE of Broadcaster.

setID

public void setID(String id)

Description copied from interface: Broadcaster

Set the ID of this Broadcaster.

Specified by:

setID in interface Broadcaster

Parameters:

id - ID of this Broadcaster

getID

public String getID()

Description copied from interface: Broadcaster

Return the ID of this Broadcaster.

Specified by:

getID in interface Broadcaster

Returns:

the ID of this Broadcaster

resumeAll

public void resumeAll()

Description copied from interface: Broadcaster

Resume all suspended responses (AtmosphereResource) added via Broadcaster.addAtmosphereResource(org.atmosphere.cpr.AtmosphereResource).

Specified by:

resumeAll in interface Broadcaster

releaseExternalResources

public void releaseExternalResources()

Description copied from interface: Broadcaster

Release external resources associated with this Broadcaster. This is useful when a Broadcaster no longer have suspended AtmosphereResource and some resource (like database connections, JMS queue, etc.) needs to be closed.

Specified by:

releaseExternalResources in interface Broadcaster

setBroadcasterLifeCyclePolicy

public void setBroadcasterLifeCyclePolicy(BroadcasterLifeCyclePolicy lifeCyclePolicy)

Description copied from interface: Broadcaster

Set the BroadcasterLifeCyclePolicy. Make sure you are selecting the right policy to avoid unexpected situations.

Specified by:

setBroadcasterLifeCyclePolicy in interface Broadcaster

Parameters:

lifeCyclePolicy - a BroadcasterLifeCyclePolicy

addBroadcasterLifeCyclePolicyListener

public void addBroadcasterLifeCyclePolicyListener(BroadcasterLifeCyclePolicyListener b)

Description copied from interface: Broadcaster

Add a BroadcasterLifeCyclePolicyListener.

Specified by:

addBroadcasterLifeCyclePolicyListener in interface Broadcaster

Parameters:

b - a BroadcasterLifeCyclePolicyListener

removeBroadcasterLifeCyclePolicyListener

public void removeBroadcasterLifeCyclePolicyListener(BroadcasterLifeCyclePolicyListener b)

Description copied from interface: Broadcaster

Remove a BroadcasterLifeCyclePolicyListener.

Specified by:

removeBroadcasterLifeCyclePolicyListener in interface Broadcaster

Parameters:

b - a BroadcasterLifeCyclePolicyListener

isDestroyed

public boolean isDestroyed()

Description copied from interface: Broadcaster

Return true if this Broadcaster has been destroyed.

Specified by:

isDestroyed in interface Broadcaster

Returns:

true if this Broadcaster has been destroyed

awaitAndBroadcast

public Future<Object> awaitAndBroadcast(Object t,
                                        long time,
                                        TimeUnit timeUnit)

Description copied from interface: Broadcaster

Await for available AtmosphereResource before broadcasting. This method will block until Broadcaster.addAtmosphereResource(AtmosphereResource) gets invoked.

Specified by:

awaitAndBroadcast in interface Broadcaster

addBroadcasterListener

public Broadcaster addBroadcasterListener(BroadcasterListener b)

Description copied from interface: Broadcaster

Add a BroadcasterListener.

Specified by:

addBroadcasterListener in interface Broadcaster

Parameters:

b - a BroadcasterListener

Returns:

this

removeBroadcasterListener

public Broadcaster removeBroadcasterListener(BroadcasterListener b)

Description copied from interface: Broadcaster

Remove a BroadcasterListener.

Specified by:

removeBroadcasterListener in interface Broadcaster

Parameters:

b - a BroadcasterListener

Returns:

this

getBroadcastHandler

protected Runnable getBroadcastHandler()

getAsyncWriteHandler

protected Runnable getAsyncWriteHandler(org.atmosphere.cpr.DefaultBroadcaster.WriteQueue writeQueue)

start

protected void start()

spawnReactor

protected void spawnReactor()

killReactiveThreads

protected void killReactiveThreads()

reactiveThreadsCount

protected int reactiveThreadsCount()

Return the default number of reactive threads that will be waiting for work when a broadcast operation is executed.

Returns:

the default number of reactive threads

push

protected void push(Entry entry)

deliverPush

protected void deliverPush(Entry entry,
                           boolean rec)

queueWriteIO

protected void queueWriteIO(AtmosphereResource r,
                            Entry entry)
                     throws InterruptedException

Throws:

InterruptedException

executeBlockingWrite

protected void executeBlockingWrite(AtmosphereResource r,
                                    Entry entry)
                             throws InterruptedException

Throws:

InterruptedException

perRequestFilter

protected boolean perRequestFilter(AtmosphereResource r,
                                   Entry msg)

executeAsyncWrite

protected void executeAsyncWrite(DefaultBroadcaster.AsyncWriteToken token)

checkCachedAndPush

protected boolean checkCachedAndPush(AtmosphereResource r,
                                     AtmosphereResourceEvent e)

retrieveTrackedBroadcast

protected boolean retrieveTrackedBroadcast(AtmosphereResource r,
                                           AtmosphereResourceEvent e)

invokeOnStateChange

protected void invokeOnStateChange(AtmosphereResource r,
                                   AtmosphereResourceEvent e)

prepareInvokeOnStateChange

protected void prepareInvokeOnStateChange(AtmosphereResource r,
                                          AtmosphereResourceEvent e)

onException

public void onException(Throwable t,
                        AtmosphereResource ar)

onException

public void onException(Throwable t,
                        AtmosphereResource ar,
                        boolean notifyAndCache)

cacheLostMessage

public void cacheLostMessage(AtmosphereResource r)

Cache the message because an unexpected exception occurred.

Parameters:

r - AtmosphereResource

cacheLostMessage

public void cacheLostMessage(AtmosphereResource r,
                             boolean force)

Cache the message because an unexpected exception occurred.

Parameters:

r - AtmosphereResource

cacheLostMessage

public void cacheLostMessage(AtmosphereResource r,
                             DefaultBroadcaster.AsyncWriteToken token)

Cache the message because an unexpected exception occurred.

Parameters:

r - AtmosphereResource

cacheLostMessage

public void cacheLostMessage(AtmosphereResource r,
                             DefaultBroadcaster.AsyncWriteToken token,
                             boolean force)

Cache the message because an unexpected exception occurred.

Parameters:

r - AtmosphereResource

setSuspendPolicy

public void setSuspendPolicy(long maxSuspendResource,
                             Broadcaster.POLICY policy)

Description copied from interface: Broadcaster

Set the maximum number of suspended AtmosphereResources. If the maximum is reached, Atmosphere will either resume AtmosphereResource using Broadcaster.POLICY.FIFO (first in first out) or Broadcaster.POLICY.REJECT the AtmosphereResource.

By default the number is unlimited.

Specified by:

setSuspendPolicy in interface Broadcaster

Parameters:

maxSuspendResource - maximum number of suspended AtmosphereResource

broadcast

public Future<Object> broadcast(Object msg)

Description copied from interface: Broadcaster

Broadcast the Object to all suspended responses, eg. invoke AtmosphereHandler.onStateChange(org.atmosphere.cpr.AtmosphereResourceEvent).

Specified by:

broadcast in interface Broadcaster

Parameters:

msg - the Object to be broadcasted

Returns:

a Future that can be used to synchronize using the Future.get()

futureDone

protected BroadcasterFuture<Object> futureDone(Object msg)

dispatchMessages

protected void dispatchMessages(Entry e)

filter

protected Object filter(Object msg)

Invoke the BroadcastFilter

Parameters:

msg -

Returns:

broadcast

public Future<Object> broadcast(Object msg,
                                AtmosphereResource r)

Description copied from interface: Broadcaster

Broadcast the Object to all suspended responses, eg. invoke AtmosphereHandler.onStateChange(org.atmosphere.cpr.AtmosphereResourceEvent) with an instance of AtmosphereResource, representing a single suspended response.

Specified by:

broadcast in interface Broadcaster

Parameters:

msg - the Object to be broadcasted

r - an AtmosphereResource

Returns:

a Future that can be used to synchronize using the Future.get()

broadcastOnResume

public Future<Object> broadcastOnResume(Object msg)

Description copied from interface: Broadcaster

Broadcast the Object when an AtmosphereResource is resumed by a timeout or when using AtmosphereResource.resume().

Specified by:

broadcastOnResume in interface Broadcaster

Parameters:

msg - the Object to be broadcasted

Returns:

a Future that can be used to synchronize using the Future.get()

broadcastOnResume

protected void broadcastOnResume(AtmosphereResource r)

broadcast

public Future<Object> broadcast(Object msg,
                                Set<AtmosphereResource> subset)

Description copied from interface: Broadcaster

Broadcast the Object to all suspended response, eg. invoke AtmosphereHandler.onStateChange(org.atmosphere.cpr.AtmosphereResourceEvent) with a Set of AtmosphereResource, representing a set of AtmosphereHandler.

Specified by:

broadcast in interface Broadcaster

Parameters:

msg - the Object to be broadcasted

subset - a Set of AtmosphereResource

Returns:

a Future that can be used to synchronize using the Future.get()

addAtmosphereResource

public Broadcaster addAtmosphereResource(AtmosphereResource r)

Description copied from interface: Broadcaster

Add a AtmosphereResource to the list of items to be notified when the Broadcaster.broadcast(java.lang.Object) is invoked.

It is strongly recommended to suspend the AtmosphereResource before adding it to a Broadcaster.

Specified by:

addAtmosphereResource in interface Broadcaster

Parameters:

r - an AtmosphereResource

Returns:

this

cacheAndSuspend

protected void cacheAndSuspend(AtmosphereResource r)

Look in the cache to see if there are messages available, and take the appropriate actions.

Parameters:

r - AtmosphereResource

notifyAndAdd

protected void notifyAndAdd(AtmosphereResource r)

entryDone

protected void entryDone(BroadcasterFuture<?> f)

notifyBroadcastListener

protected void notifyBroadcastListener()

notifyOnAddAtmosphereResourceListener

protected void notifyOnAddAtmosphereResourceListener(AtmosphereResource r)

notifyOnRemoveAtmosphereResourceListener

protected void notifyOnRemoveAtmosphereResourceListener(AtmosphereResource r)

removeAtmosphereResource

public Broadcaster removeAtmosphereResource(AtmosphereResource r)

Description copied from interface: Broadcaster

Remove a AtmosphereResource from the list of s to be notified when the Broadcaster.broadcast(java.lang.Object) is invoked.

Specified by:

removeAtmosphereResource in interface Broadcaster

Parameters:

r - an AtmosphereResource

Returns:

this

removeAtmosphereResource

protected Broadcaster removeAtmosphereResource(AtmosphereResource r,
                                               boolean executeDone)

notifyIdleListener

protected void notifyIdleListener()

notifyDestroyListener

protected void notifyDestroyListener()

notifyEmptyListener

protected void notifyEmptyListener()

setBroadcasterConfig

public void setBroadcasterConfig(BroadcasterConfig bc)

Description copied from interface: Broadcaster

Set the BroadcasterConfig instance.

Specified by:

setBroadcasterConfig in interface Broadcaster

Parameters:

bc - Configuration to be set.

getBroadcasterConfig

public BroadcasterConfig getBroadcasterConfig()

Description copied from interface: Broadcaster

Return the current BroadcasterConfig.

Specified by:

getBroadcasterConfig in interface Broadcaster

Returns:

the current BroadcasterConfig

delayBroadcast

public Future<Object> delayBroadcast(Object o)

Description copied from interface: Broadcaster

Delay the broadcast operation. The Object will be broadcasted when Broadcaster.broadcast(java.lang.Object) is invoked the first time.

Specified by:

delayBroadcast in interface Broadcaster

Parameters:

o - the Object to be broadcasted

Returns:

a Future that can be used to synchronize using the Future.get()

delayBroadcast

public Future<Object> delayBroadcast(Object o,
                                     long delay,
                                     TimeUnit t)

Description copied from interface: Broadcaster

Delay the broadcast operation. The Object will be broadcasted once the specified delay expires or when Broadcaster.broadcast(java.lang.Object) is invoked the first time.

Specified by:

delayBroadcast in interface Broadcaster

Parameters:

o - the Object to be broadcasted

delay - Amount of time to delay

t - the TimeUnit of the delay

Returns:

a Future that can be used to synchronize using the Future.get()

scheduleFixedBroadcast

public Future<Object> scheduleFixedBroadcast(Object o,
                                             long period,
                                             TimeUnit t)

Description copied from interface: Broadcaster

Broadcast periodically. The Object will be broadcasted after every period specified time frame expires. If the TimeUnit is set to null, the Object will be broadcasted when the first Broadcaster.broadcast(java.lang.Object) is invoked.

Specified by:

scheduleFixedBroadcast in interface Broadcaster

Parameters:

o - the Object to be broadcasted

period - Every so often broadcast.

t - a TimeUnit of period.

Returns:

a Future that can be used to synchronize using the Future.get()

scheduleFixedBroadcast

public Future<Object> scheduleFixedBroadcast(Object o,
                                             long waitFor,
                                             long period,
                                             TimeUnit t)

Description copied from interface: Broadcaster

Broadcast periodically. The Object will be broadcasted after every period specified time frame expires. If the TimeUnit is set null, the Object will be broadcasted when the first Broadcaster.broadcast(java.lang.Object) is invoked.

Specified by:

scheduleFixedBroadcast in interface Broadcaster

Parameters:

o - the Object to be broadcasted

waitFor - Wait for that long before first broadcast

period - The period inbetween broadcast.

t - a TimeUnit of waitFor and period.

Returns:

a Future that can be used to synchronize using the Future.get()

toString

public String toString()

Overrides:

toString in class Object