io.druid.indexing.overlord

Class TaskQueue

java.lang.Object

io.druid.indexing.overlord.TaskQueue

public class TaskQueue
extends Object

Interface between task producers and the task runner.

This object accepts tasks from producers using add(io.druid.indexing.common.task.Task) and manages delivery of these tasks to a TaskRunner. Tasks will run in a mostly-FIFO order, with deviations when the natural next task is not ready in time (based on its Task.isReady(io.druid.indexing.common.actions.TaskActionClient) method).

For persistence, we save all new tasks and task status changes using a TaskStorage object.

Constructor Summary

Constructors

Constructor and Description
TaskQueue(TaskQueueConfig config, TaskStorage taskStorage, TaskRunner taskRunner, TaskActionClientFactory taskActionClientFactory, TaskLockbox taskLockbox, com.metamx.emitter.service.ServiceEmitter emitter)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(Task task) Adds some work to the queue and the underlying task storage facility with a generic "running" status.
void	shutdown(String taskId) Shuts down a task if it has not yet finished.
void	start() Starts this task queue.
void	stop() Shuts down the queue.

Methods inherited from class java.lang.Object

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

Constructor Detail

TaskQueue

@Inject
public TaskQueue(TaskQueueConfig config,
                TaskStorage taskStorage,
                TaskRunner taskRunner,
                TaskActionClientFactory taskActionClientFactory,
                TaskLockbox taskLockbox,
                com.metamx.emitter.service.ServiceEmitter emitter)

Method Detail

start

public void start()

Starts this task queue. Allows add(Task) to accept new tasks.

stop

public void stop()

Shuts down the queue.

add

public boolean add(Task task)
            throws EntryExistsException

Adds some work to the queue and the underlying task storage facility with a generic "running" status.

Parameters:

task - task to add

Returns:

true

Throws:

EntryExistsException - if the task already exists

shutdown

public void shutdown(String taskId)

Shuts down a task if it has not yet finished.

Parameters:

taskId - task to kill