Package io.temporal.workflow

Interface WorkflowSemaphore

  • public interface WorkflowSemaphore
    Workflow semaphore is an alternative to Semaphore that is deterministic and compatible with Temporal's concurrency model. API is designed to be used in a workflow code only. It is not allowed to be used in an activity code.

    In Temporal concurrency model, only one thread in a workflow code can execute at a time.

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void acquire()
      Acquires a permit from this semaphore, blocking until one is available.
      void acquire​(int permits)
      Acquires the given number of permits from this semaphore, blocking until all are available.
      void release()
      Releases a permit, returning it to the semaphore.
      void release​(int permits)
      Releases the given number of permits, returning them to the semaphore.
      boolean tryAcquire()
      Acquires the given number of permits from this semaphore, only if all are available at the time of invocation.
      boolean tryAcquire​(int permits)
      Acquires the given number of permits from this semaphore, only if all are available at the time of invocation.
      boolean tryAcquire​(int permits, java.time.Duration timeout)
      Acquires the given number of permits from this semaphore, if all become available within the given waiting time.
      boolean tryAcquire​(java.time.Duration timeout)
      Acquires a permit from this semaphore, if one becomes available within the given waiting time.

    • Method Detail

      • acquire

        void acquire()
        Acquires a permit from this semaphore, blocking until one is available.

        Acquires a permit, if one is available and returns immediately, reducing the number of available permits by one.

        Throws:
        CanceledFailure - if thread (or current CancellationScope was canceled).

      • acquire

        void acquire​(int permits)
        Acquires the given number of permits from this semaphore, blocking until all are available.

        Acquires the given number of permits, if they are available, and returns immediately, reducing the number of available permits by the given amount.

        Parameters:
        permits - the number of permits to acquire
        Throws:
        CanceledFailure - if thread (or current CancellationScope was canceled).
        java.lang.IllegalArgumentException - if permits is negative

      • tryAcquire

        boolean tryAcquire()
        Acquires the given number of permits from this semaphore, only if all are available at the time of invocation.

        Acquires a permit, if one is available and returns immediately, with the value true, reducing the number of available permits by one.

        Returns:
        true if the permit was acquired and false otherwise

      • tryAcquire

        boolean tryAcquire​(java.time.Duration timeout)
        Acquires a permit from this semaphore, if one becomes available within the given waiting time.

        Acquires a permit, if one is available and returns immediately, with the value true, reducing the number of available permits by one.

        Parameters:
        timeout - the maximum time to wait for a permit
        Returns:
        true if a permit was acquired and false if the waiting time elapsed before a permit was acquired
        Throws:
        CanceledFailure - if thread (or current CancellationScope was canceled).

      • tryAcquire

        boolean tryAcquire​(int permits)
        Acquires the given number of permits from this semaphore, only if all are available at the time of invocation.

        Acquires the given number of permits, if they are available, and returns immediately, with the value true, reducing the number of available permits by the given amount.

        If insufficient permits are available then this method will return immediately with the value false and the number of available permits is unchanged.

        Parameters:
        permits - the number of permits to acquire
        Returns:
        true if the permits were acquired and false otherwise
        Throws:
        java.lang.IllegalArgumentException - if permits is negative

      • tryAcquire

        boolean tryAcquire​(int permits,
                   java.time.Duration timeout)
        Acquires the given number of permits from this semaphore, if all become available within the given waiting time.

        Acquires the given number of permits, if they are available and returns immediately, with the value true, reducing the number of available permits by the given amount.

        Parameters:
        permits - the number of permits to acquire
        timeout - the maximum duration to wait for a permit
        Returns:
        true if the permits was acquired and false if the waiting time elapsed before a permit was acquired
        Throws:
        CanceledFailure - if thread (or current CancellationScope was canceled).
        java.lang.IllegalArgumentException - if permits is negative

      • release

        void release()
        Releases a permit, returning it to the semaphore.

        There is no requirement that a coroutine that releases a permit must have acquired that permit by calling acquire(). Correct usage of a semaphore is established by programming convention in the application.

      • release

        void release​(int permits)
        Releases the given number of permits, returning them to the semaphore.

        There is no requirement that a coroutine that releases a permit must have acquired that permit by calling acquire(). Correct usage of a semaphore is established by programming convention in the application.

        Parameters:
        permits - the number of permits to release
        Throws:
        java.lang.IllegalArgumentException - if permits is negative