Class ThreadManager (2.0.0)

public final class ThreadManager

ThreadManager exposes a ThreadFactory that allows App Engine applications to spawn new threads.

Refer to this discussion of threads for drawbacks of thread usage and possible alternatives.

Inheritance

java.lang.Object > ThreadManager

Static Methods

backgroundThreadFactory()

public static ThreadFactory backgroundThreadFactory()

Returns a ThreadFactory that will create threads that are independent of the current request.

This ThreadFactory can currently only be used by backends.

Note that calling ThreadFactory#newThread on the returned instance may throw any of the unchecked exceptions mentioned by #createBackgroundThread.

Returns
Type Description
ThreadFactory

createBackgroundThread(Runnable runnable)

public static Thread createBackgroundThread(Runnable runnable)

Create a new Thread that executes runnable independent of the current request. Calling this method is equivalent to invoking ThreadFactory#newThread on the ThreadFactory returned from #backgroundThreadFactory.

This method can currently only be used by backends.

Parameter
Name Description
runnable Runnable
Returns
Type Description
Thread

createThreadForCurrentRequest(Runnable runnable)

public static Thread createThreadForCurrentRequest(Runnable runnable)

Create a new Thread that executes runnable for the duration of the current request. Calling this method is equivalent to invoking ThreadFactory#newThread on the ThreadFactory returned from #currentRequestThreadFactory. This thread will be interrupted at the end of the current request and must complete within the request deadline. If it fails to, the instance containing it may be terminated.

Parameter
Name Description
runnable Runnable
Returns
Type Description
Thread

currentRequestThreadFactory()

public static ThreadFactory currentRequestThreadFactory()

Returns a ThreadFactory which will create threads scoped to the current request. These threads will be interrupted at the end of the current request and must complete within the request deadline. If they fail to, the instance containing them may be terminated.

The principal reason to use this method is so that the created threads can make App Engine API calls (com.google.appengine.api.*). In general, threads not associated with a request cannot make these API calls.

The returned factory is typically used with a call like java.util.concurrent.Executors#newCachedThreadPool(ThreadFactory). Do not use the ExecutorService returned by this call after the request that created it has completed.

Note that calling ThreadFactory#newThread on the returned instance may throw any of the unchecked exceptions mentioned by #createBackgroundThread.

Returns
Type Description
ThreadFactory

currentRequestThreadFactoryOptional()

public static Optional<ThreadFactory> currentRequestThreadFactoryOptional()

Returns an Optional ThreadFactory which will create threads scoped to the current request. These threads will be interrupted at the end of the current request and must complete within the request deadline. If they fail to, the instance containing them may be terminated.

If this method is not called from an App Engine request thread, returns an empty Optional instance.

The principal reason to use this method is so that the created threads can make App Engine API calls (com.google.appengine.api.*). In general, threads not associated with a request cannot make these API calls.

The returned factory is typically used with a call like java.util.concurrent.Executors#newCachedThreadPool(ThreadFactory). Do not use the ExecutorService returned by this call after the request that created it has completed.

Note that calling ThreadFactory#newThread on the returned instance may throw any of the unchecked exceptions mentioned by #createBackgroundThread.

Returns
Type Description
Optional<ThreadFactory>

Constructors

ThreadManager()

public ThreadManager()