com.facebook.buck.core.graph.transformation.executor

Interface DepsAwareExecutor<ResultType,TaskType extends DepsAwareTask<ResultType,TaskType>>

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

DefaultDepsAwareExecutor, DefaultDepsAwareExecutorWithLocalStack, JavaExecutorBackedDefaultDepsAwareExecutor, ToposortBasedDepsAwareExecutor

public interface DepsAwareExecutor<ResultType,TaskType extends DepsAwareTask<ResultType,TaskType>>
extends AutoCloseable

A specialized Executor that executes DepsAwareTask. This executor will attempt to maintain maximum concurrency, while completing dependencies of each supplied work first.

It is guaranteed that the dependencies from DepsAwareTask.getDepsSupplier() will be completed before the work itself is executed.

In terms of thread safety, it is guaranteed that for the same DepsAwareTask, its deps supplier from DepsAwareTask.getDepsSupplier() will be executed before its callable from DepsAwareTask.getCallable() is executed. That is, the supplier execution "happens before" the callable execution, but potentially in different threads, where "happens before" is the standard event ordering a -> b. There is an at least once guarantee on the number of invocations of the deps supplier, and an exactly once guarantee on the callable. There is no guarantee of synchronization between different instances of DepsAwareTask other than that its dependencies will be completed before the callable is evaluated.

Method Summary

Modifier and Type	Method and Description
void	close() Shuts down the executor workers immediately.
TaskType	createTask(Callable<ResultType> callable)
TaskType	createThrowingTask(Callable<ResultType> callable, ThrowingSupplier<com.google.common.collect.ImmutableSet<TaskType>,Exception> prereqSupplier, ThrowingSupplier<com.google.common.collect.ImmutableSet<TaskType>,Exception> depsSupplier)
boolean	isShutdown()
Future<ResultType>	submit(TaskType task)
com.google.common.collect.ImmutableList<Future<ResultType>>	submitAll(Collection<TaskType> tasks) Same as submit(DepsAwareTask) except for multiple tasks.

Method Detail

close

void close()

Shuts down the executor workers immediately. This does not shutdown the underlying executor backing the DepsAwareExecutor

Specified by:

close in interface AutoCloseable

isShutdown

boolean isShutdown()

Returns:

true iff close() has been called

createThrowingTask

TaskType createThrowingTask(Callable<ResultType> callable,
                            ThrowingSupplier<com.google.common.collect.ImmutableSet<TaskType>,Exception> prereqSupplier,
                            ThrowingSupplier<com.google.common.collect.ImmutableSet<TaskType>,Exception> depsSupplier)

Returns:

a new DepsAwareTask with two stages of dependency computation

createTask

TaskType createTask(Callable<ResultType> callable)

Returns:

a new DepsAwareTask that can be executed in this executor

submit

Future<ResultType> submit(TaskType task)

Parameters:

task - the DepsAwareTask to run

Returns:

a future of the result

submitAll

com.google.common.collect.ImmutableList<Future<ResultType>> submitAll(Collection<TaskType> tasks)

Same as submit(DepsAwareTask) except for multiple tasks.