org.hobbit.core.components

Class AbstractSequencingTaskGenerator

java.lang.Object

org.hobbit.core.components.AbstractComponent

org.hobbit.core.components.AbstractCommandReceivingComponent

org.hobbit.core.components.AbstractTaskGenerator

org.hobbit.core.components.AbstractSequencingTaskGenerator

All Implemented Interfaces:

Closeable, AutoCloseable, CommandReceivingComponent, Component, GeneratedDataReceivingComponent, RabbitQueueFactory

public abstract class AbstractSequencingTaskGenerator
extends AbstractTaskGenerator

Extension of the AbstractTaskGenerator that offers methods to wait for acknowledgements for single tasks. The workflow for waiting for a task is

• generate a task and a task id (for the latter AbstractTaskGenerator.getNextTaskId() should be used)
• set the task id which will be sent next using setTaskIdToWaitFor(String)
• send the task to the system with AbstractTaskGenerator.sendTaskToSystemAdapter(String, byte[]) and AbstractTaskGenerator.sendTaskToEvalStorage(String, long, byte[])
• wait for the acknowledgement using waitForAck()

Note that the acknowledgements only work if the evaluation storage is configured to send acknowledgements for the single tasks.

Author:

Michael Röder (roeder@informatik.uni-leipzig.de)

Field Summary

Fields

Modifier and Type	Field and Description
protected com.rabbitmq.client.Channel	ackChannel Channel on which the acknowledgements are received.
private long	ackTimeout Timeout for the acknowledgement.
private static long	DEFAULT_ACK_TIMEOUT Default timeout for the acknowledgement.
private static org.slf4j.Logger	LOGGER
private String	taskId Id of the task the generator is waiting for an acknowledgement.
private Semaphore	taskIdMutex Semaphore used to wait for the acknowledgement.

Fields inherited from class org.hobbit.core.components.AbstractTaskGenerator

consumer, dataGen2TaskGenQueue, runFlag, taskGen2EvalStoreQueue, taskGen2SystemQueue

Fields inherited from class org.hobbit.core.components.AbstractCommandReceivingComponent

cmdChannel, defaultContainerType

Fields inherited from class org.hobbit.core.components.AbstractComponent

connection, NUMBER_OF_RETRIES_TO_CONNECT_TO_RABBIT_MQ, rabbitMQHostName, START_WAITING_TIME_BEFORE_RETRY

Constructor Summary

Constructors

Constructor and Description
AbstractSequencingTaskGenerator()

Method Summary

Modifier and Type	Method and Description
void	close()
protected void	handleAck(byte[] body) Handles the acknowledgement messages.
void	init() This method initializes the component.
protected void	setTaskIdToWaitFor(String taskId) Method to set the task id for which the task generator will wait when calling waitForAck().
protected boolean	waitForAck() Method to wait for the acknowledgement of a task with the given Id.

Methods inherited from class org.hobbit.core.components.AbstractTaskGenerator

generateTask, getGeneratorId, getNextTaskId, getNumberOfGenerators, receiveCommand, receiveGeneratedData, run, sendTaskToEvalStorage, sendTaskToSystemAdapter

Methods inherited from class org.hobbit.core.components.AbstractCommandReceivingComponent

addCommandHeaderId, createContainer, createContainer, handleCmd, sendToCmdQueue, sendToCmdQueue, sendToCmdQueue, stopContainer

Methods inherited from class org.hobbit.core.components.AbstractComponent

createDefaultRabbitQueue, generateSessionQueueName, getHobbitSessionId

Methods inherited from class java.lang.Object

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

Field Detail

LOGGER

private static final org.slf4j.Logger LOGGER

DEFAULT_ACK_TIMEOUT

private static final long DEFAULT_ACK_TIMEOUT

Default timeout for the acknowledgement.

See Also:

Constant Field Values

ackTimeout

private long ackTimeout

Timeout for the acknowledgement.

taskId

private String taskId

Id of the task the generator is waiting for an acknowledgement.

taskIdMutex

private Semaphore taskIdMutex

Semaphore used to wait for the acknowledgement.

ackChannel

protected com.rabbitmq.client.Channel ackChannel

Channel on which the acknowledgements are received.

Constructor Detail

AbstractSequencingTaskGenerator

public AbstractSequencingTaskGenerator()

Method Detail

init

public void init()
          throws Exception

Description copied from interface: Component

This method initializes the component.

Specified by:

init in interface Component

Overrides:

init in class AbstractTaskGenerator

Throws:

Exception - if an error occurs during the initialization

handleAck

protected void handleAck(byte[] body)

Handles the acknowledgement messages.

Parameters:

body - the body of the acknowledgement message

setTaskIdToWaitFor

protected void setTaskIdToWaitFor(String taskId)

Method to set the task id for which the task generator will wait when calling waitForAck().

Parameters:

taskId - id of the task for which the acknowledgement should be received

waitForAck

protected boolean waitForAck()

Method to wait for the acknowledgement of a task with the given Id.

Returns:

true if the acknowledgement has been received, false if the timeout has been reached or the method has been interrupted.

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class AbstractTaskGenerator

Throws:

IOException