io.druid.indexing.overlord

Class TaskLockbox

java.lang.Object

io.druid.indexing.overlord.TaskLockbox

public class TaskLockbox
extends Object

Remembers which tasks have locked which intervals. Tasks are permitted to lock an interval if no other task outside their group has locked an overlapping interval for the same datasource. When a task locks an interval, it is assigned a version string that it can use to publish segments.

Constructor Summary

Constructors

Constructor and Description
TaskLockbox(TaskStorage taskStorage)

Method Summary

Methods

Modifier and Type	Method and Description
List<TaskLock>	findLocksForTask(Task task) Return the currently-active locks for some task.
TaskLock	lock(Task task, org.joda.time.Interval interval) Acquires a lock on behalf of a task.
void	syncFromStorage() Wipe out our current in-memory state and resync it from our bundled TaskStorage.
com.google.common.base.Optional<TaskLock>	tryLock(Task task, org.joda.time.Interval interval) Attempt to lock a task, without removing it from the queue.
void	unlock(Task task) Release all locks for a task.
void	unlock(Task task, org.joda.time.Interval interval) Release lock held for a task on a particular interval.

Methods inherited from class java.lang.Object

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

Constructor Detail

TaskLockbox

@Inject
public TaskLockbox(TaskStorage taskStorage)

Method Detail

syncFromStorage

public void syncFromStorage()

Wipe out our current in-memory state and resync it from our bundled TaskStorage.

lock

public TaskLock lock(Task task,
            org.joda.time.Interval interval)
              throws InterruptedException

Acquires a lock on behalf of a task. Blocks until the lock is acquired. Throws an exception if the lock cannot be acquired.

Parameters:

task - task to acquire lock for

interval - interval to lock

Returns:

acquired TaskLock

Throws:

InterruptedException - if the lock cannot be acquired

tryLock

public com.google.common.base.Optional<TaskLock> tryLock(Task task,
                                                org.joda.time.Interval interval)

Attempt to lock a task, without removing it from the queue. Equivalent to the long form of tryLock with no preferred version.

Parameters:

task - task that wants a lock

interval - interval to lock

Returns:

lock version if lock was acquired, absent otherwise

findLocksForTask

public List<TaskLock> findLocksForTask(Task task)

Return the currently-active locks for some task.

Parameters:

task - task for which to locate locks

Returns:

currently-active locks for the given task

unlock

public void unlock(Task task,
          org.joda.time.Interval interval)

Release lock held for a task on a particular interval. Does nothing if the task does not currently hold the mentioned lock.

Parameters:

task - task to unlock

interval - interval to unlock

unlock

public void unlock(Task task)

Release all locks for a task. Does nothing if the task is not currently locked.

Parameters:

task - task to unlock