Package org.cometd.oort

Class OortMasterLong

java.lang.Object

org.eclipse.jetty.util.component.AbstractLifeCycle

org.cometd.oort.OortService<R,C>

org.cometd.oort.OortMasterService<Long,OortMasterLong.Context>

org.cometd.oort.OortMasterLong

All Implemented Interfaces:

EventListener, Bayeux.BayeuxListener, ConfigurableServerChannel.ServerChannelListener, ServerChannel.MessageListener, org.eclipse.jetty.util.component.LifeCycle

public class OortMasterLong
extends OortMasterService<Long,OortMasterLong.Context>

A distributed counter service to be deployed on a Oort cluster that modifies a long value hosted in a "master" node.

Instances of this service may be used as unique ID generator, or as unique counter across the cluster, for example to aggregate values from different nodes, such as the number of users connected to each node.

Applications may call methods addAndGet(long, Callback) or getAndAdd(long, Callback) providing the amount to add (it may be negative) and a OortMasterLong.Callback object that will be invoked on the requesting node when the result has been computed and transmitted back by the "master" node.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	OortMasterLong.Callback	Callback invoked when the result of the operation on the counter is available, or when the operation failed.
protected static class	OortMasterLong.Context

Nested classes/interfaces inherited from class org.cometd.oort.OortService

OortService.Request, OortService.Result<U>, OortService.ServerContext

Nested classes/interfaces inherited from class org.eclipse.jetty.util.component.AbstractLifeCycle

org.eclipse.jetty.util.component.AbstractLifeCycle.AbstractLifeCycleListener

Nested classes/interfaces inherited from interface org.cometd.bayeux.server.ConfigurableServerChannel.ServerChannelListener

ConfigurableServerChannel.ServerChannelListener.Weak

Nested classes/interfaces inherited from interface org.eclipse.jetty.util.component.LifeCycle

org.eclipse.jetty.util.component.LifeCycle.Listener

Field Summary

Fields inherited from class org.cometd.oort.OortService

logger

Fields inherited from class org.eclipse.jetty.util.component.AbstractLifeCycle

FAILED, RUNNING, STARTED, STARTING, STOPPED, STOPPING

Constructor Summary

Constructors

Constructor	Description
OortMasterLong(Oort oort, String name, boolean master)
OortMasterLong(Oort oort, String name, boolean master, long initial)

Method Summary

Modifier and Type	Method	Description
boolean	addAndGet(long delta, OortMasterLong.Callback callback)	Adds the given delta and then invokes the given callback with the counter value after the addition.
boolean	get(OortMasterLong.Callback callback)	Retrieves the value from the "master" node and then invokes the given callback with the result value.
boolean	getAndAdd(long delta, OortMasterLong.Callback callback)	Adds the given delta and then invokes the given callback with the counter value before the addition.
protected long	getValue()
protected OortService.Result<Long>	onForward(OortService.Request request)	Subclasses must implement this method, that runs on the owner node, to implement the action functionality.
protected void	onForwardFailed(Object failure, OortMasterLong.Context context)	Subclasses must implement this method, that runs on the requesting node, to complete the functionality after the action failed on the owner node.
protected void	onForwardSucceeded(Long result, OortMasterLong.Context context)	Subclasses must implement this method, that runs on the requesting node, to complete the functionality after the action has been successfully run on the owner node.

Methods inherited from class org.cometd.oort.OortMasterService

doStart, doStop, getMasterOortURL, isMaster

Methods inherited from class org.cometd.oort.OortService

forward, getLocalSession, getName, getOort, getTimeout, onForwardMessage, onMessage, onResultMessage, setTimeout, toString

Methods inherited from class org.eclipse.jetty.util.component.AbstractLifeCycle

addLifeCycleListener, getState, getState, getStopTimeout, isFailed, isRunning, isStarted, isStarting, isStopped, isStopping, removeLifeCycleListener, setStopTimeout, start, stop

Methods inherited from class java.lang.Object

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

Constructor Details

OortMasterLong

public OortMasterLong(Oort oort, String name, boolean master)

OortMasterLong

public OortMasterLong(Oort oort, String name, boolean master, long initial)

Parameters:

oort - the oort this instance is associated to

name - the name of this service

master - whether this service lives on the "master" node

initial - the initial local value

Method Details

getValue

protected long getValue()

Returns:

the local value, which makes sense only if called on the "master" node.

get

public boolean get(OortMasterLong.Callback callback)

Retrieves the value from the "master" node and then invokes the given callback with the result value.

Parameters:

callback - the callback invoked when the result is available

Returns:

whether the request could be forwarded to the "master" node

addAndGet

public boolean addAndGet(long delta, OortMasterLong.Callback callback)

Adds the given delta and then invokes the given callback with the counter value after the addition. The counter value may be already out of date at the moment of the invocation of the callback.

Parameters:

delta - the value to add, may be negative

callback - the callback invoked when the result is available

Returns:

whether the request could be forwarded to the "master" node

See Also:

getAndAdd(long, Callback)

getAndAdd

public boolean getAndAdd(long delta, OortMasterLong.Callback callback)

Adds the given delta and then invokes the given callback with the counter value before the addition.

Parameters:

delta - the value to add, may be negative

callback - the callback invoked when the result is available

Returns:

whether the request could be forwarded to the "master" node

See Also:

addAndGet(long, Callback)

onForward

protected OortService.Result<Long> onForward(OortService.Request request)

Description copied from class: OortService

Subclasses must implement this method, that runs on the owner node, to implement the action functionality.

The result to return is OortService.Result.success(Object) or OortService.Result.failure(Object) if the implementation of this method was able to find the entity on which the action functionality was meant to be applied, or OortService.Result.ignore(Object) if the entity was not found.

Specified by:

onForward in class OortService<Long,OortMasterLong.Context>

Parameters:

request - the request containing the parameter passed from OortService.forward(String, Object, Object)

Returns:

the result containing the data that will be passed to OortService.onForwardSucceeded(Object, Object)

onForwardSucceeded

protected void onForwardSucceeded(Long result, OortMasterLong.Context context)

Description copied from class: OortService

Subclasses must implement this method, that runs on the requesting node, to complete the functionality after the action has been successfully run on the owner node.

Specified by:

onForwardSucceeded in class OortService<Long,OortMasterLong.Context>

Parameters:

result - the result of the action

context - the opaque context from OortService.forward(String, Object, Object)

onForwardFailed

protected void onForwardFailed(Object failure, OortMasterLong.Context context)

Description copied from class: OortService

Subclasses must implement this method, that runs on the requesting node, to complete the functionality after the action failed on the owner node.

Specified by:

onForwardFailed in class OortService<Long,OortMasterLong.Context>

Parameters:

failure - the failure of the action

context - the opaque context from OortService.forward(String, Object, Object)