org.apache.twill.internal

Class AbstractZKServiceController

java.lang.Object

org.apache.twill.internal.AbstractExecutionServiceController

org.apache.twill.internal.AbstractZKServiceController

All Implemented Interfaces:

com.google.common.util.concurrent.Service, ServiceController

Direct Known Subclasses:

AbstractTwillController

public abstract class AbstractZKServiceController
extends AbstractExecutionServiceController

An abstract base class for implementing a ServiceController using ZooKeeper as a means for communicating with the remote service. This is designed to work in pair with the AbstractTwillService.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.twill.api.ServiceController

ServiceController.TerminationStatus

Nested classes/interfaces inherited from interface com.google.common.util.concurrent.Service

com.google.common.util.concurrent.Service.Listener, com.google.common.util.concurrent.Service.State

Field Summary

Fields

Modifier and Type	Field and Description
protected ZKClient	zkClient

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractZKServiceController(RunId runId, ZKClient zkClient)

Method Summary

Modifier and Type	Method and Description
protected abstract void	doShutDown() Called during shutdown.
protected abstract void	doStartUp() Called during startup.
protected void	forceShutDown()
protected String	getInstancePath() Returns the zookeeper node path for the ephemeral instance node for this runId.
protected com.google.common.util.concurrent.ListenableFuture<com.google.common.util.concurrent.Service.State>	getStopMessageFuture()
protected abstract void	instanceNodeFailed(Throwable cause) Called when failed to fetch from live instance node.
protected abstract void	instanceNodeUpdated(NodeData nodeData) Called when an update on the live instance node is detected.
com.google.common.util.concurrent.ListenableFuture<Command>	sendCommand(Command command) Sends a user command to the running application.
com.google.common.util.concurrent.ListenableFuture<Command>	sendCommand(String runnableName, Command command) Sends a user command to the given runnable of the running application.
protected <V> com.google.common.util.concurrent.ListenableFuture<V>	sendMessage(org.apache.twill.internal.state.Message message, V result) Sends a Message to the remote service.
protected void	shutDown()
protected void	startUp()
protected void	watchInstanceNode()

Methods inherited from class org.apache.twill.internal.AbstractExecutionServiceController

addListener, awaitTerminated, awaitTerminated, executor, getRunId, getTerminationStatus, isRunning, onRunning, onTerminated, setTerminationStatus, start, startAndWait, state, stop, stopAndWait, terminate

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.twill.api.ServiceController

kill

Methods inherited from interface com.google.common.util.concurrent.Service

awaitRunning, awaitRunning, failureCause, startAsync, stopAsync

Field Detail

zkClient

protected final ZKClient zkClient

Constructor Detail

AbstractZKServiceController

protected AbstractZKServiceController(RunId runId,
                                      ZKClient zkClient)

Method Detail

sendCommand

public final com.google.common.util.concurrent.ListenableFuture<Command> sendCommand(Command command)

Description copied from interface: ServiceController

Sends a user command to the running application.

Parameters:

command - The command to send.

Returns:

A Future that will be completed when the command is successfully processed by the target application.

sendCommand

public final com.google.common.util.concurrent.ListenableFuture<Command> sendCommand(String runnableName,
                                                                                     Command command)

Description copied from interface: ServiceController

Sends a user command to the given runnable of the running application.

Parameters:

runnableName - Name of the TwillRunnable.

command - The command to send.

Returns:

A Future that will be completed when the command is successfully processed by the target runnable.

startUp

protected final void startUp()

Specified by:

startUp in class AbstractExecutionServiceController

shutDown

protected final void shutDown()

Specified by:

shutDown in class AbstractExecutionServiceController

sendMessage

protected final <V> com.google.common.util.concurrent.ListenableFuture<V> sendMessage(org.apache.twill.internal.state.Message message,
                                                                                      V result)

Sends a Message to the remote service. Returns a future that will be completed when the message has been processed.

Type Parameters:

V - Type of the result.

Parameters:

message - The message to send.

result - Object to set into the future when message is being processed.

Returns:

A ListenableFuture that will be completed when the message has been processed.

getStopMessageFuture

protected final com.google.common.util.concurrent.ListenableFuture<com.google.common.util.concurrent.Service.State> getStopMessageFuture()

doStartUp

protected abstract void doStartUp()

Called during startup. Executed in the startup thread.

doShutDown

protected abstract void doShutDown()

Called during shutdown. Executed in the shutdown thread.

instanceNodeUpdated

protected abstract void instanceNodeUpdated(NodeData nodeData)

Called when an update on the live instance node is detected.

Parameters:

nodeData - The updated live instance node data or null if there is an error when fetching the node data.

instanceNodeFailed

protected abstract void instanceNodeFailed(Throwable cause)

Called when failed to fetch from live instance node.

Parameters:

cause - The cause of failure of null if cause is unknown.

forceShutDown

protected void forceShutDown()

watchInstanceNode

protected final void watchInstanceNode()

getInstancePath

protected final String getInstancePath()

Returns the zookeeper node path for the ephemeral instance node for this runId.