Package org.cometd.oort

Class OortMasterService<R,C>

java.lang.Object

org.eclipse.jetty.util.component.AbstractLifeCycle

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

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

Type Parameters:

R - the result type

C - the opaque context type

All Implemented Interfaces:

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

Direct Known Subclasses:

OortMasterLong

public abstract class OortMasterService<R,C>
extends OortService<R,C>

OortMasterService extends OortService to allow applications to perform actions on entities that always live in a "master" node.

Applications may have entities that are naturally owned by any node. For example, in a chat application a chat room may be created by a user in any node, and be owned by the node the user that created it is connected to.

There are cases, however, where entities cannot be owned by any node, but instead must be owned by one node only, usually referred to as the "master" node.

A typical example of such an entity is a unique (across the cluster) ID generator that produces IDs in the form of long - the primitive Java type - values, or a service that accesses a storage (such as a file system) that is only available on a particular node, etc.

OortMasterService makes easier to write services that perform actions on entities that must be owned by a single node only. There is one instance of OortMasterService with the same name for each node, but only one of them is the "master". Then, applications may call getMasterOortURL() to get the Oort URL of the "master" node, and pass that Oort URL to OortService.forward(String, Object, Object) as described in OortService.

Nested Class Summary

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
OortMasterService(Oort oort, String name, boolean master)

Method Summary

Modifier and Type	Method	Description
protected void	doStart()
protected void	doStop()
String	getMasterOortURL()
boolean	isMaster()

Methods inherited from class org.cometd.oort.OortService

forward, getLocalSession, getName, getOort, getTimeout, onForward, onForwardFailed, onForwardMessage, onForwardSucceeded, 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

OortMasterService

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

Parameters:

oort - the oort this instance is associated to

name - the name of this service

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

Method Details

isMaster

public boolean isMaster()

Returns:

whether this node is the "master" node

getMasterOortURL

public String getMasterOortURL()

Returns:

the "master" Oort URL, or null if the "master" node is down.

doStart

protected void doStart() throws Exception

Overrides:

doStart in class OortService<R,C>

Throws:

Exception

doStop

protected void doStop() throws Exception

Overrides:

doStop in class OortService<R,C>

Throws:

Exception