com.facebook.buck.support.bgtasks

Class AsyncBackgroundTaskManager

java.lang.Object

com.facebook.buck.support.bgtasks.BackgroundTaskManager

com.facebook.buck.support.bgtasks.AsyncBackgroundTaskManager

public class AsyncBackgroundTaskManager
extends BackgroundTaskManager

Asynchronous-enabled implementation of BackgroundTaskManager. Tasks run in a pool. Takes a blocking flag in constructor; when blocking=true, manager waits for tasks to complete before returning control to client. When blocking=false, manager schedules on a separate thread and does not wait for task completion. Scheduler thread is paused whenever a new command begins.

NOTE: only a manager on buckd should be set/instantiated to nonblocking mode, otherwise unexpected behavior might occur

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AsyncBackgroundTaskManager(int nThreads)

Method Summary

Modifier and Type	Method and Description
protected Map<Class<?>,com.facebook.buck.support.bgtasks.ManagedBackgroundTask<?>>	getCancellableTasks() Return map of tasks that might be cancelled (i.e.
protected int	getCommandsRunning()
TaskManagerCommandScope	getNewScope(BuildId buildId, boolean blocking) Returns a new TaskManagerCommandScope for a build on this manager.
protected Queue<com.facebook.buck.support.bgtasks.ManagedBackgroundTask<?>>	getScheduledTasks() Return list of currently scheduled (not yet submitted) tasks.
protected boolean	isShutDown() Check if the manager is shut down.
static AsyncBackgroundTaskManager	of() Same as of() except with the default number of threads.
static AsyncBackgroundTaskManager	of(int nThreads) Constructs an AsyncBackgroundTaskManager.
void	shutdown(long timeout, TimeUnit units) Shut down manager, waiting until given timeout for tasks to finish.
void	shutdownNow() Shut down scheduler and pool threads.
protected void	startScheduling()

Methods inherited from class java.lang.Object

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

Constructor Detail

AsyncBackgroundTaskManager

protected AsyncBackgroundTaskManager(int nThreads)

Method Detail

of

public static AsyncBackgroundTaskManager of(int nThreads)

Constructs an AsyncBackgroundTaskManager. If in nonblocking mode, sets up a scheduler thread and pool for tasks.

Parameters:

nThreads - (optional) number of threads in pool. defaults to DEFAULT_THREADS if not provided

of

public static AsyncBackgroundTaskManager of()

Same as of() except with the default number of threads.

getNewScope

public TaskManagerCommandScope getNewScope(BuildId buildId,
                                           boolean blocking)

Description copied from class: BackgroundTaskManager

Returns a new TaskManagerCommandScope for a build on this manager. The TaskManagerCommandScope lives for the duration of the command such that it's TaskManagerCommandScope.close() will trigger the tasks scheduled to be ran.

Specified by:

getNewScope in class BackgroundTaskManager

Parameters:

buildId - unique identifier BuildId of a command that created a scope

blocking - whether the current command should wait for tasks to finish on exit

startScheduling

protected void startScheduling()

shutdownNow

public void shutdownNow()

Shut down scheduler and pool threads.

Specified by:

shutdownNow in class BackgroundTaskManager

shutdown

public void shutdown(long timeout,
                     TimeUnit units)
              throws InterruptedException

Description copied from class: BackgroundTaskManager

Shut down manager, waiting until given timeout for tasks to finish.

Specified by:

shutdown in class BackgroundTaskManager

Parameters:

timeout - timeout for tasks to finish

units - units of timeout

Throws:

InterruptedException

getScheduledTasks

protected Queue<com.facebook.buck.support.bgtasks.ManagedBackgroundTask<?>> getScheduledTasks()

Return list of currently scheduled (not yet submitted) tasks. For debugging/testing.

Returns:

list of currently scheduled tasks

getCancellableTasks

protected Map<Class<?>,com.facebook.buck.support.bgtasks.ManagedBackgroundTask<?>> getCancellableTasks()

Return map of tasks that might be cancelled (i.e. not run) if a task with the same action is subsequently scheduled. Tasks in this map are currently scheduled, not yet run. For debugging/testing.

Returns:

map of cancellable tasks

isShutDown

protected boolean isShutDown()

Check if the manager is shut down. "Shut down" means that all executors are terminated and manager is no longer accepting new task submissions. For debugging/testing.

Returns:

true if manager is shut down, false otherwise

getCommandsRunning

protected int getCommandsRunning()