Package org.hobbit.core.components

Class AbstractSequencingTaskGenerator

java.lang.Object

org.hobbit.core.components.AbstractComponent

org.hobbit.core.components.AbstractCommandReceivingComponent

org.hobbit.core.components.AbstractPlatformConnectorComponent

org.hobbit.core.components.AbstractTaskGenerator

org.hobbit.core.components.AbstractSequencingTaskGenerator

All Implemented Interfaces:

Closeable, AutoCloseable, CommandReceivingComponent, Component, GeneratedDataReceivingComponent, PlatformConnector

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 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	Description
protected com.rabbitmq.client.Channel	ackChannel	Channel on which the acknowledgments 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	seqTaskId	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.AbstractCommandReceivingComponent

cmdChannel, cmdQueueFactory, defaultContainerType

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

connectionFactory, incomingDataQueueFactory, NUMBER_OF_RETRIES_TO_CONNECT_TO_RABBIT_MQ, outgoingDataQueuefactory, rabbitMQHostName, START_WAITING_TIME_BEFORE_RETRY

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

consumer, dataGenReceiver, runFlag, sender2EvalStore, sender2System

Constructor Summary

Constructors

Constructor	Description
AbstractSequencingTaskGenerator()

Method Summary

Modifier and Type	Method	Description
void	close()
protected void	handleAck(byte[] body)	Handles the acknowledgement messages.
void	init()	This method initializes the component.
protected void	sendTaskToSystemAdapter(String taskIdString, byte[] data)	Sends the given task with the given task id and data to the system and blocks until an acknowledgement has been received for the task or the timeout has been reached.
protected boolean	sendTaskToSystemAdapterInSequence(String taskIdString, byte[] data)	Sends the given task with the given task id and data to the system and blocks until an acknowledgement has been received for the task or the timeout has been reached.
void	setAckTimeout(long ackTimeout)	Setter for the maximum time the task generator waits for an acknowledgement.
protected void	setTaskIdToWaitFor(String taskId)	Deprecated. It is not necessary anymore since its usage has been integrated into the sendTaskToSystemAdapterInSequence(String, byte[]) method.
private boolean	waitForAck()	Method to wait for the acknowledgement of a task with the given Id.

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

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

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

createConnection, generateSessionQueueName, getHobbitSessionId

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

addContainerObserver, createContainer, getFactoryForIncomingCmdQueues, getFactoryForIncomingDataQueues, getFactoryForOutgoingCmdQueues, getFactoryForOutgoingDataQueues, stopContainer

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

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

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.

seqTaskId

private String seqTaskId

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 acknowledgments 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

sendTaskToSystemAdapter

protected void sendTaskToSystemAdapter(String taskIdString,
                                       byte[] data)
                                throws IOException

Sends the given task with the given task id and data to the system and blocks until an acknowledgement has been received for the task or the timeout has been reached. If an information is needed which of these two cases happened sendTaskToSystemAdapterInSequence(String, byte[]) should be used.

Overrides:

sendTaskToSystemAdapter in class AbstractTaskGenerator

Parameters:

taskIdString - the id of the task

data - the data of the task

Throws:

IOException - if there is an error during the sending

sendTaskToSystemAdapterInSequence

protected boolean sendTaskToSystemAdapterInSequence(String taskIdString,
                                                    byte[] data)
                                             throws IOException

Sends the given task with the given task id and data to the system and blocks until an acknowledgement has been received for the task or the timeout has been reached. The return value shows which of these two cases happened.

Parameters:

taskIdString - the task id

data - the data of the task

Returns:

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

Throws:

IOException - if there is an error during the sending

setTaskIdToWaitFor

@Deprecated
protected void setTaskIdToWaitFor(String taskId)

Deprecated. It is not necessary anymore since its usage has been integrated into the sendTaskToSystemAdapterInSequence(String, byte[]) method.

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

private 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.

setAckTimeout

public void setAckTimeout(long ackTimeout)

Setter for the maximum time the task generator waits for an acknowledgement.

Parameters:

ackTimeout - the new timeout in milliseconds

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class AbstractTaskGenerator

Throws:

IOException