Module jdk.incubator.concurrent
Package jdk.incubator.concurrent

Class StructuredTaskScope.ShutdownOnSuccess<T>

java.lang.Object
jdk.incubator.concurrent.StructuredTaskScope<T>
jdk.incubator.concurrent.StructuredTaskScope.ShutdownOnSuccess<T>
Type Parameters:
T - the result type
All Implemented Interfaces:
AutoCloseable
Enclosing class:
StructuredTaskScope<T>
public static final class StructuredTaskScope.ShutdownOnSuccess<T> extends StructuredTaskScope<T>
A StructuredTaskScope that captures the result of the first subtask to complete successfully. Once captured, it invokes the shutdown method to interrupt unfinished threads and wakeup the owner. The policy implemented by this class is intended for cases where the result of any subtask will do ("invoke any") and where the results of other unfinished subtask are no longer needed.

Unless otherwise specified, passing a null argument to a method in this class will cause a NullPointerException to be thrown.

Since:
19

  • Constructor Details

    • ShutdownOnSuccess

      public ShutdownOnSuccess(String name, ThreadFactory factory)
      Constructs a new ShutdownOnSuccess with the given name and thread factory. The task scope is optionally named for the purposes of monitoring and management. The thread factory is used to create threads when tasks are forked. The task scope is owned by the current thread.

      This method captures the current thread's scoped value bindings for inheritance by threads created in the task scope. The Tree Structure section in the class description details how parent-child relations are established implicitly for the purpose of inheritance of scoped value bindings.

      Parameters:
      name - the name of the task scope, can be null
      factory - the thread factory

    • ShutdownOnSuccess

      public ShutdownOnSuccess()
      Constructs a new unnamed ShutdownOnSuccess that creates virtual threads.

      This constructor is equivalent to invoking the 2-arg constructor with a name of null and a thread factory that creates virtual threads.

  • Method Details

    • handleComplete

      protected void handleComplete(Future<T> future)
      Shut down the given task scope when invoked for the first time with a Future for a task that completed with a result.
      Overrides:
      handleComplete in class StructuredTaskScope<T>
      Parameters:
      future - the completed task
      See Also:

    • join

      public StructuredTaskScope.ShutdownOnSuccess<T> join() throws InterruptedException
      Wait for all threads to finish or the task scope to shut down. This method waits until all threads started in the task scope finish execution (of both task and handleComplete method), the shutdown method is invoked to shut down the task scope, or the current thread is interrupted.

      This method may only be invoked by the task scope owner.

      Overrides:
      join in class StructuredTaskScope<T>
      Returns:
      this task scope
      Throws:
      IllegalStateException - if this task scope is closed
      WrongThreadException - if the current thread is not the owner
      InterruptedException - if interrupted while waiting

    • joinUntil

      public StructuredTaskScope.ShutdownOnSuccess<T> joinUntil(Instant deadline) throws InterruptedException, TimeoutException
      Wait for all threads to finish or the task scope to shut down, up to the given deadline. This method waits until all threads started in the task scope finish execution (of both task and handleComplete method), the shutdown method is invoked to shut down the task scope, the current thread is interrupted, or the deadline is reached.

      This method may only be invoked by the task scope owner.

      Overrides:
      joinUntil in class StructuredTaskScope<T>
      Parameters:
      deadline - the deadline
      Returns:
      this task scope
      Throws:
      IllegalStateException - if this task scope is closed
      WrongThreadException - if the current thread is not the owner
      InterruptedException - if interrupted while waiting
      TimeoutException - if the deadline is reached while waiting

    • result

      public T result() throws ExecutionException
      Returns the result of the first subtask that completed with a result.

      When no subtask completed with a result but a task completed with an exception then ExecutionException is thrown with the exception as the cause. If only cancelled subtasks were notified to the handleComplete method then CancellationException is thrown.

      API Note:
      This method is intended to be invoked by the task scope owner after it has invoked join (or joinUntil). A future release may add enforcement to prevent the method being called by other threads or before joining.
      Returns:
      the result of the first subtask that completed with a result
      Throws:
      ExecutionException - if no subtasks completed with a result but a subtask completed with an exception
      CancellationException - if all subtasks were cancelled
      IllegalStateException - if the handle method was not invoked with a completed subtask

    • result

      public <X extends Throwable> T result(Function<Throwable,? extends X> esf) throws X
      Returns the result of the first subtask that completed with a result, otherwise throws an exception produced by the given exception supplying function.

      When no subtask completed with a result but a subtask completed with an exception then the exception supplying function is invoked with the exception. If only cancelled subtasks were notified to the handleComplete method then the exception supplying function is invoked with a CancellationException.

      API Note:
      This method is intended to be invoked by the task scope owner after it has invoked join (or joinUntil). A future release may add enforcement to prevent the method being called by other threads or before joining.
      Type Parameters:
      X - type of the exception to be thrown
      Parameters:
      esf - the exception supplying function
      Returns:
      the result of the first subtask that completed with a result
      Throws:
      X - if no subtask completed with a result
      IllegalStateException - if the handle method was not invoked with a completed subtask