ai.grakn.engine.backgroundtasks

Interface TaskManager

All Known Implementing Classes:

AbstractTaskManager, InMemoryTaskManager

public interface TaskManager

Method Summary

Modifier and Type	Method and Description
Set<UUID>	getAllTasks() Returns a Set of all tasks in the system - this includes Completed, Running, Dead, etc.
Set<UUID>	getTasks(TaskStatus taskStatus) Return a Set of all tasks with a matching @TaskStatus.
TaskState	getTaskState(UUID uuid) Return the full TaskState object for a given task, containing full task metadata including the status change messages and reqesterNames as provided in the stopTask/pauseTask/resumeTask and restartTask methods.
UUID	scheduleRecurringTask(BackgroundTask task, long delay, long period) Schedule a task for recurring execution at every @period interval and after an initial @delay.
UUID	scheduleTask(BackgroundTask task, long delay) Schedule a single shot/one off BackgroundTask to run after a @delay in milliseconds.
TaskManager	stopTask(UUID uuid, String requesterName, String message) Stop a Scheduled, Paused or Running task.

Method Detail

scheduleTask

UUID scheduleTask(BackgroundTask task,
                  long delay)

Schedule a single shot/one off BackgroundTask to run after a @delay in milliseconds.

Parameters:

task - Any object implementing the BackgroundTask interface that is to be scheduled for later execution.

delay - Delay after which the @task object should be executed, may be null.

Returns:

Assigned UUID of task scheduled for later execution.

scheduleRecurringTask

UUID scheduleRecurringTask(BackgroundTask task,
                           long delay,
                           long period)

Schedule a task for recurring execution at every @period interval and after an initial @delay.

Parameters:

task - Any object implementing the BackgroundTask interface that is to be scheduled for later execution.

delay - Long delay after which the @task object should be executed, may be null.

period - Long interval between subsequent calls to @task.start().

Returns:

Assigned UUID of task scheduled for later execution.

stopTask

TaskManager stopTask(UUID uuid,
                     String requesterName,
                     String message)

Stop a Scheduled, Paused or Running task. Task's .stop() method will be called to perform any cleanup and the task is killed afterwards.

Parameters:

uuid - UUID of task to stop.

requesterName - Optional String to denote who requested this call; used for status reporting and may be null.

message - Optional String denoting the reason for stopping the task; used for status reporting and may be null.

Returns:

Instance of the class implementing TaskManager.

getTaskState

TaskState getTaskState(UUID uuid)

Return the full TaskState object for a given task, containing full task metadata including the status change messages and reqesterNames as provided in the stopTask/pauseTask/resumeTask and restartTask methods.

Parameters:

uuid - UUID of task to stop.

Returns:

TaskState object. See @TaskState.

getAllTasks

Set<UUID> getAllTasks()

Returns a Set of all tasks in the system - this includes Completed, Running, Dead, etc.

Returns:

Set<> of task UUID's

getTasks

Set<UUID> getTasks(TaskStatus taskStatus)

Return a Set of all tasks with a matching @TaskStatus. Example: // Return all tasks which failed to complete execution. Set failedTasks = myTaskManager.getTasks(TaskStatus.DEAD);

Parameters:

taskStatus - See TaskStatus enum.

Returns:

Set<> of task UUID's matching the given @taskStatus.