ai.grakn.engine.postprocessing

Class PostProcessingTask

java.lang.Object

ai.grakn.engine.postprocessing.PostProcessingTask

All Implemented Interfaces:

BackgroundTask

public class PostProcessingTask
extends Object
implements BackgroundTask

Task that control when postprocessing starts.

This task begins only if enough time has passed (configurable) since the last time a job was added.

Author:

alexandraorth, fppt

Constructor Summary

Constructors

Constructor and Description
PostProcessingTask()

Method Summary

Modifier and Type	Method and Description
static TaskConfiguration	createConfig(String keyspace, String config) Helper method which creates the task config needed in order to execute a PP task
static TaskState	createTask(Class creator) Helper method which creates PP Task States.
void	pause() Called to suspend the execution of a currently running task.
boolean	resume(java.util.function.Consumer<TaskCheckpoint> saveCheckpoint, TaskCheckpoint lastCheckpoint) This method may be called when resuming from a paused state or recovering from a crash or failure of any kind.
boolean	start(java.util.function.Consumer<TaskCheckpoint> saveCheckpoint, TaskConfiguration configuration, TaskSubmitter taskSubmitter) Apply CASTING and RESOURCE post processing jobs the concept ids in the provided configuration
boolean	stop() Called to stop execution of the task, may be called on a running or paused task.

Methods inherited from class java.lang.Object

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

Constructor Detail

PostProcessingTask

public PostProcessingTask()

Method Detail

start

public boolean start(java.util.function.Consumer<TaskCheckpoint> saveCheckpoint,
                     TaskConfiguration configuration,
                     TaskSubmitter taskSubmitter)

Apply CASTING and RESOURCE post processing jobs the concept ids in the provided configuration

Specified by:

start in interface BackgroundTask

Parameters:

saveCheckpoint - Checkpointing is not implemented in this task, so this parameter is not used.

configuration - Configuration containing the IDs to be post processed.

taskSubmitter - Allows followup tasks to be submitted for processing

Returns:

True if successful.

stop

public boolean stop()

Description copied from interface: BackgroundTask

Called to stop execution of the task, may be called on a running or paused task. Task should stop gracefully.

Specified by:

stop in interface BackgroundTask

Returns:

true if the task was successfully stopped, or false if it could not be stopped. TODO: Should we allow start() to be called after stop()?

pause

public void pause()

Description copied from interface: BackgroundTask

Called to suspend the execution of a currently running task. The object may be destroyed after this call. TODO: stop running

Specified by:

pause in interface BackgroundTask

resume

public boolean resume(java.util.function.Consumer<TaskCheckpoint> saveCheckpoint,
                      TaskCheckpoint lastCheckpoint)

Description copied from interface: BackgroundTask

This method may be called when resuming from a paused state or recovering from a crash or failure of any kind.

Specified by:

resume in interface BackgroundTask

Parameters:

saveCheckpoint - Consumer which can be called at any time to save a state checkpoint that would allow the task to resume from this point should it crash.

lastCheckpoint - The last checkpoint as sent to saveCheckpoint.

createTask

public static TaskState createTask(Class creator)

Helper method which creates PP Task States.

Parameters:

creator - The class which is creating the task

Returns:

The executable postprocessing task state

createConfig

public static TaskConfiguration createConfig(String keyspace,
                                             String config)

Helper method which creates the task config needed in order to execute a PP task

Parameters:

keyspace - The keyspace of the graph to execute this on.

config - The config which contains the concepts to post process

Returns:

The task configuration encapsulating the above details in a manner executable by the task runner