alluxio.heartbeat

Class HeartbeatScheduler

java.lang.Object

alluxio.heartbeat.HeartbeatScheduler

@ThreadSafe
public final class HeartbeatScheduler
extends Object

This class can be used for controlling heartbeat execution of a thread. In particular, the await(String) method can be used to wait for a thread to start waiting to be scheduled and the schedule(String) method can be used to schedule a thread that is waiting to be scheduled. The contract of this class is that the schedule(String) method should only be called for threads that are in fact waiting to be scheduled. If this contract is not met, concurrent execution of a thread and the heartbeat scheduler logic to schedule the thread can lead to a deadlock. For an example of how to use the HeartbeatScheduler, see unit test of HeartbeatThread.

Method Summary

Modifier and Type	Method and Description
static void	addTimer(ScheduledTimer timer)
static void	await(String name) Waits for the given thread to be ready to be scheduled.
static void	await(String name, long time, TimeUnit unit) Waits until the given thread can be executed, throwing an unchecked exception of the given timeout expires.
static void	clearTimer(String name) Removes a timer name from the scheduler if it exists.
static void	execute(String name) Convenience method for executing a heartbeat and waiting for it to complete.
static Set<String>	getThreadNames()
static void	removeTimer(ScheduledTimer timer) Removes a timer from the scheduler.
static void	schedule(String threadName) Schedules execution of a heartbeat for the given thread.

Methods inherited from class java.lang.Object

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

Method Detail

addTimer

public static void addTimer(ScheduledTimer timer)

Parameters:

timer - a timer to add to the scheduler

clearTimer

public static void clearTimer(String name)

Removes a timer name from the scheduler if it exists.

Parameters:

name - the name to clear

removeTimer

public static void removeTimer(ScheduledTimer timer)

Removes a timer from the scheduler. This method will fail if the timer is not in the scheduler.

Parameters:

timer - the timer to remove

getThreadNames

public static Set<String> getThreadNames()

Returns:

the set of threads present in the scheduler

schedule

public static void schedule(String threadName)

Schedules execution of a heartbeat for the given thread.

Parameters:

threadName - a name of the thread for which heartbeat is to be executed

await

public static void await(String name)
                  throws InterruptedException

Waits for the given thread to be ready to be scheduled.

Parameters:

name - a name of the thread to wait for

Throws:

InterruptedException - if the waiting thread is interrupted

await

public static void await(String name,
                         long time,
                         TimeUnit unit)
                  throws InterruptedException

Waits until the given thread can be executed, throwing an unchecked exception of the given timeout expires.

Parameters:

name - a name of the thread to wait for

time - the maximum time to wait

unit - the time unit of the time argument

Throws:

InterruptedException - if the waiting thread is interrupted

execute

public static void execute(String name)
                    throws InterruptedException

Convenience method for executing a heartbeat and waiting for it to complete.

Parameters:

name - the name of the heartbeat to execute

Throws:

InterruptedException - if the waiting thread is interrupted