com.twitter.concurrent

Offer

trait Offer[+T] extends AnyRef

An offer to communicate with another process. The offer is parameterized on the type of the value communicated. An offer that sends a value typically has type {{Unit}}. An offer is activated by synchronizing it, which is done with sync().

Note that Offers are persistent values -- they may be synchronized multiple times. They represent a standing offer of communication, not a one-shot event.

The synchronization protocol

Synchronization is performed via a two-phase commit process. prepare() commenses the transaction, and when the other party is ready, it returns with a transaction object, Tx[T]. This must then be ackd or nackd. If both parties acknowledge, Tx.ack() returns with a commit object, containing the value. This finalizes the transaction. Please see the Tx documentation for more details on that phase of the protocol.

Note that a user should never perform this protocol themselves -- synchronization should always be done with sync().

Future interrupts are propagated, and failure is passed through. It is up to the implementor of the Offer to decide on failure semantics, but they are always passed through in all of the combinators.

Self Type
Offer[T]
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Abstract Value Members

  1. abstract def prepare(): Future[Tx[T]]

    Prepare a new transaction.

    Prepare a new transaction. This is the first stage of the 2 phase commit. This is typically only called by the offer implementation directly or by combinators.

Concrete Value Members

  1. final def !=(arg0: Any): Boolean

    Definition Classes
    AnyRef → Any

  2. final def ##(): Int

    Definition Classes
    AnyRef → Any

  3. final def ==(arg0: Any): Boolean

    Definition Classes
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  4. def ?: Future[T]

    Alias for synchronize.

  5. def ??: T

    Synchronize, blocking for the result.

  6. def andThen(f: ⇒ Unit): Unit

    Synchronize (discarding the value), and then invoke the given closure.

    Synchronize (discarding the value), and then invoke the given closure. Convenient for loops.

  7. def apply[U](f: (T) ⇒ U): Offer[U]

    Synonym for map().

    Synonym for map(). Useful in combination with Offer.choose() and Offer.select()

  8. final def asInstanceOf[T0]: T0

    Definition Classes
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  9. def clone(): AnyRef

    Attributes
    protected[java.lang]
    Definition Classes
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    Annotations
    @throws( ... )

  10. def const[U](f: ⇒ U): Offer[U]

    Like {{map}}, but to a constant (call-by-name).

  11. final def eq(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef

  12. def equals(arg0: Any): Boolean

    Definition Classes
    AnyRef → Any

  13. def finalize(): Unit

    Attributes
    protected[java.lang]
    Definition Classes
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    Annotations
    @throws( classOf[java.lang.Throwable] )

  14. def foreach(f: (T) ⇒ Unit): Unit

    Synchronize on this offer indefinitely, invoking the given {{f}} with each successfully synchronized value.

    Synchronize on this offer indefinitely, invoking the given {{f}} with each successfully synchronized value. A receiver can use this to enumerate over all received values.

  15. final def getClass(): Class[_]

    Definition Classes
    AnyRef → Any

  16. def hashCode(): Int

    Definition Classes
    AnyRef → Any

  17. final def isInstanceOf[T0]: Boolean

    Definition Classes
    Any

  18. def map[U](f: (T) ⇒ U): Offer[U]

    Map this offer of type {{T}} into one of type {{U}}.

    Map this offer of type {{T}} into one of type {{U}}. The translation (performed by {{f}}) is done after the {{Offer[T]}} has successfully synchronized.

  19. final def ne(arg0: AnyRef): Boolean

    Definition Classes
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  20. final def notify(): Unit

    Definition Classes
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  21. final def notifyAll(): Unit

    Definition Classes
    AnyRef

  22. def or[U](other: Offer[U]): Offer[Either[T, U]]

  23. def orElse[U >: T](other: Offer[U]): Offer[U]

    An offer that, when synchronized, attempts to synchronize {{this}} immediately, and if it fails, synchronizes on {{other}} instead.

    An offer that, when synchronized, attempts to synchronize {{this}} immediately, and if it fails, synchronizes on {{other}} instead. This is useful for providing default values. Eg.:

    offer orElse Offer.const { computeDefaultValue() }

  24. def sync(): Future[T]

    Synchronizes this offer, returning a future representing the result of the synchronization.

  25. def syncWait(): T

    Synchronize this offer, blocking for the result.

    Synchronize this offer, blocking for the result. See {{sync()}} and {{com.twitter.util.Future.apply()}}

  26. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef

  27. def toString(): String

    Definition Classes
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  28. final def wait(): Unit

    Definition Classes
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    Annotations
    @throws( ... )

  29. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
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    @throws( ... )

  30. final def wait(arg0: Long): Unit

    Definition Classes
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    @throws( ... )

Deprecated Value Members

  1. def apply(): Future[T]

    Synonym for sync()

    Synonym for sync()

    Annotations
    @deprecated
    Deprecated

    (Since version 5.x) use sync() instead

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