com.bigdata.ha

Class FutureTaskInvariantMon<T>

java.lang.Object

java.util.concurrent.FutureTask<T>

com.bigdata.concurrent.FutureTaskMon<T>

com.bigdata.ha.FutureTaskInvariantMon<T>

Type Parameters:

T - The generic type of the future.

All Implemented Interfaces:

QuorumListener, Runnable, Future<T>, RunnableFuture<T>

public abstract class FutureTaskInvariantMon<T>
extends FutureTaskMon<T>
implements QuorumListener

A Future that allows you to cancel a computation if an invariant is violated. This class is specifically designed to monitor quorum related invariants for HA.

Once an invariant is established, listening for the relevant quorum events commences and a check is made to verify that the invariant holds on entry. This pattern ensures there is no possibility of a missed event.

This FutureTask wrapper will return the value of the Callable (or the specified result for the Runnable) iff the task completes successfully without the invariant being violated.

Author:

Bryan Thompson

Constructor Summary

Constructors

Constructor and Description
FutureTaskInvariantMon(Callable<T> callable, Quorum<HAGlue,QuorumService<HAGlue>> quorum)
FutureTaskInvariantMon(Runnable runnable, T result, Quorum<HAGlue,QuorumService<HAGlue>> quorum)

Method Summary

Methods

Modifier and Type	Method and Description
void	assertInPipeline(UUID serviceId) Establish an invariant that the specified service is in the quorum pipeline.
void	assertJoined(UUID serviceId) Establish an invariant that the specified service is joined with the met quorum.
void	assertMember(UUID serviceId) Establish an invariant that the specified service is a member of the quorum.
void	assertNotJoined(UUID serviceId) Establish an invariant that the specified service is a not joined with the met quorum.
void	assertQuorumFullyMet() Establish an invariant that the quorum is fully met.
void	assertQuorumMet() Establish an invariant that the quorum is met and remains met on the same token (the one specified to the constructor).
protected abstract void	establishInvariants() Concrete implementations use this callback hook to establish the invariants to be monitored.
void	notify(QuorumEvent e) Any QuorumEvent must be checked to see if it matches an Invariant trigger
void	run()

Methods inherited from class com.bigdata.concurrent.FutureTaskMon

cancel

Methods inherited from class java.util.concurrent.FutureTask

done, get, get, isCancelled, isDone, runAndReset, set, setException

Methods inherited from class java.lang.Object

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

Constructor Detail

FutureTaskInvariantMon

public FutureTaskInvariantMon(Callable<T> callable,
                      Quorum<HAGlue,QuorumService<HAGlue>> quorum)

FutureTaskInvariantMon

public FutureTaskInvariantMon(Runnable runnable,
                      T result,
                      Quorum<HAGlue,QuorumService<HAGlue>> quorum)

Method Detail

establishInvariants

protected abstract void establishInvariants()

Concrete implementations use this callback hook to establish the invariants to be monitored.

run

public void run()

Hooked to notice when the task has been started.

Hook to manage listener registration and establish invariants.

Specified by:

run in interface Runnable

Specified by:

run in interface RunnableFuture<T>

Overrides:

run in class FutureTaskMon<T>

assertMember

public void assertMember(UUID serviceId)

Establish an invariant that the specified service is a member of the quorum.

Parameters:

serviceId - The service.

assertJoined

public void assertJoined(UUID serviceId)

Establish an invariant that the specified service is joined with the met quorum.

Parameters:

serviceId - The service.

assertNotJoined

public void assertNotJoined(UUID serviceId)

Establish an invariant that the specified service is a not joined with the met quorum.

Parameters:

serviceId - The service.

assertInPipeline

public void assertInPipeline(UUID serviceId)

Establish an invariant that the specified service is in the quorum pipeline.

Parameters:

serviceId - The service.

assertQuorumMet

public void assertQuorumMet()

Establish an invariant that the quorum is met and remains met on the same token (the one specified to the constructor).

assertQuorumFullyMet

public void assertQuorumFullyMet()

Establish an invariant that the quorum is fully met.

notify

public void notify(QuorumEvent e)

Any QuorumEvent must be checked to see if it matches an Invariant trigger

Specified by:

notify in interface QuorumListener