Package com.google.gerrit.server.git

Interface WorkQueue.TaskParker

All Superinterfaces:

WorkQueue.TaskListener

All Known Implementing Classes:

WorkQueue.TaskParker.NoOp

Enclosing class:

WorkQueue

public static interface WorkQueue.TaskParker
extends WorkQueue.TaskListener

Register a TaskParker from a plugin like this:

bind(TaskListener.class).annotatedWith(Exports.named("MyParker")).to(MyParker.class);

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	WorkQueue.TaskParker.NoOp

Method Summary

Modifier and Type	Method	Description
boolean	isReadyToStart(WorkQueue.Task<?> task)	Determine whether a WorkQueue.Task is ready to run or whether it should get parked.
void	onNotReadyToStart(WorkQueue.Task<?> task)	This method will be called after this WorkQueue.TaskParker returns true from isReadyToStart(Task) and another WorkQueue.TaskParker returns false, thus preventing the start.

Methods inherited from interface com.google.gerrit.server.git.WorkQueue.TaskListener

onStart, onStop

Method Details

isReadyToStart

boolean isReadyToStart(WorkQueue.Task<?> task)

Determine whether a WorkQueue.Task is ready to run or whether it should get parked.

Tasks that are not ready to run will get parked and will not run until all WorkQueue.TaskParkers return true from this method for the WorkQueue.Task. This method may be called more than once, but will always be followed by a call to onNotReadyToStart(Task) before being called again.

Resources should be acquired in this method via non-blocking means to avoid delaying the executor from calling onNotReadyToStart(Task) on other WorkQueue.TaskParkers holding resources.

Parameters:

task - the WorkQueue.Task being considered for starting/parking

Returns:

a boolean indicating if the given WorkQueue.Task is ready to run (true) or should be parked (false)

onNotReadyToStart

void onNotReadyToStart(WorkQueue.Task<?> task)

This method will be called after this WorkQueue.TaskParker returns true from isReadyToStart(Task) and another WorkQueue.TaskParker returns false, thus preventing the start.

Implementors should use this method to free any resources acquired in isReadyToStart(Task) based on the expectation that the task would start. Those resources can be re-acquired when isReadyToStart(Task) is called again later.

Parameters:

task - the WorkQueue.Task that was prevented from starting by another WorkQueue.TaskParker