ForkJoinPool.IManagedBlocker Interface
Definition
Important
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Interface for extending managed parallelism for tasks running
in ForkJoinPool
s.
[Android.Runtime.Register("java/util/concurrent/ForkJoinPool$ManagedBlocker", "", "Java.Util.Concurrent.ForkJoinPool/IManagedBlockerInvoker")]
public interface ForkJoinPool.IManagedBlocker : Android.Runtime.IJavaObject, IDisposable, Java.Interop.IJavaPeerable
[<Android.Runtime.Register("java/util/concurrent/ForkJoinPool$ManagedBlocker", "", "Java.Util.Concurrent.ForkJoinPool/IManagedBlockerInvoker")>]
type ForkJoinPool.IManagedBlocker = interface
interface IJavaObject
interface IDisposable
interface IJavaPeerable
- Attributes
- Implements
Remarks
Interface for extending managed parallelism for tasks running in ForkJoinPool
s.
A ManagedBlocker
provides two methods. Method #isReleasable
must return true
if blocking is not necessary. Method #block
blocks the current thread if necessary (perhaps internally invoking isReleasable
before actually blocking). These actions are performed by any thread invoking ForkJoinPool#managedBlock(ManagedBlocker)
. The unusual methods in this API accommodate synchronizers that may, but don't usually, block for long periods. Similarly, they allow more efficient internal handling of cases in which additional workers may be, but usually are not, needed to ensure sufficient parallelism. Toward this end, implementations of method isReleasable
must be amenable to repeated invocation. Neither method is invoked after a prior invocation of isReleasable
or block
returns true
.
For example, here is a ManagedBlocker based on a ReentrantLock:
{@code
class ManagedLocker implements ManagedBlocker {
final ReentrantLock lock;
boolean hasLock = false;
ManagedLocker(ReentrantLock lock) { this.lock = lock; }
public boolean block() {
if (!hasLock)
lock.lock();
return true;
}
public boolean isReleasable() {
return hasLock || (hasLock = lock.tryLock());
}
}}
Here is a class that possibly blocks waiting for an item on a given queue:
{@code
class QueueTaker<E> implements ManagedBlocker {
final BlockingQueue<E> queue;
volatile E item = null;
QueueTaker(BlockingQueue<E> q) { this.queue = q; }
public boolean block() throws InterruptedException {
if (item == null)
item = queue.take();
return true;
}
public boolean isReleasable() {
return item != null || (item = queue.poll()) != null;
}
public E getItem() { // call after pool.managedBlock completes
return item;
}
}}
Java documentation for java.util.concurrent.ForkJoinPool.ManagedBlocker
.
Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.
Properties
Handle |
Gets the JNI value of the underlying Android object. (Inherited from IJavaObject) |
IsReleasable | |
JniIdentityHashCode |
Returns the value of |
JniManagedPeerState |
State of the managed peer. (Inherited from IJavaPeerable) |
JniPeerMembers |
Member access and invocation support. (Inherited from IJavaPeerable) |
PeerReference |
Returns a JniObjectReference of the wrapped Java object instance. (Inherited from IJavaPeerable) |
Methods
Block() |
Possibly blocks the current thread, for example waiting for a lock or condition. |
Disposed() |
Called when the instance has been disposed. (Inherited from IJavaPeerable) |
DisposeUnlessReferenced() |
If there are no outstanding references to this instance, then
calls |
Finalized() |
Called when the instance has been finalized. (Inherited from IJavaPeerable) |
SetJniIdentityHashCode(Int32) |
Set the value returned by |
SetJniManagedPeerState(JniManagedPeerStates) | (Inherited from IJavaPeerable) |
SetPeerReference(JniObjectReference) |
Set the value returned by |
UnregisterFromRuntime() |
Unregister this instance so that the runtime will not return it from future Java.Interop.JniRuntime+JniValueManager.PeekValue invocations. (Inherited from IJavaPeerable) |
Extension Methods
JavaCast<TResult>(IJavaObject) |
Performs an Android runtime-checked type conversion. |
JavaCast<TResult>(IJavaObject) | |
GetJniTypeName(IJavaPeerable) |