Trait/Object

io.reactors

Events

Related Docs: object Events | package reactors

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trait Events[T] extends AnyRef

A basic event stream.

Event streams are special objects that may produce events of a certain type T. Clients may subscribe side-effecting functions (i.e. callbacks) to these events with onReaction, onEvent, onMatch and on -- each of these methods will invoke the callback when an event is produced, but some may be more suitable depending on the use-case.

An event stream produces events until it unreacts. After the event stream unreacts, it never produces an event again.

Event streams can also be manipulated using declarative combinators such as map, filter, until, after and scanPast:

def positiveSquares(r: Events[Int]) = r.map(x => x * x).filter(_ != 0)

With the exception of onX family of methods, and unless otherwise specified, operators passed to these declarative combinators should be pure -- they should not have any side-effects.

The result of applying a declarative combinator on Events[T] is usually another Events[S], possibly with a type parameter S different from T. Event sink combinators, such as onEvent, return a Subscription object used to unsubscribe from their event source.

Combinators that start with the prefix on, to, pipe or get are called *sink combinators*. Calling these combinators subscribes to the event stream and creates a subscription object. The event source is from there on responsible for propagating events to sink combinators until it either *unreacts*, meaning that it will not emit any other events, or the event sink gets *unsubscribed*. The event sink can be unsubscribed by calling the unsubscribe method of the Subscription object. The client is responsible for unsubscribing from an event source once the events are no longer needed. Failure to do so risks *time leaks*, a form of resource leak in which the program gets slower and slower (because it needs to propagate no longer needed events).

Event streams are specialized for Int, Long and Double.

Every event stream is bound to a specific Reactor, the basic unit of concurrency. Within a reactor, at most a single event stream propagates events at a time. An event stream will only produce events during the execution of that reactor -- events are never triggered on a different reactor. It is forbidden to share event streams between reactors.

T

type of the events in this event stream

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  3. by Ensuring
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Abstract Value Members

  1. abstract def onReaction(observer: Observer[T]): Subscription

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    Registers a new observer to this event stream.

    Registers a new observer to this event stream.

    The observer argument may be invoked multiple times -- whenever an event is produced, or an exception occurs, and at most once when the event stream is terminated. After the event stream terminates, no events or exceptions are propagated on this event stream any more.

    returns

    a subscription for unsubscribing from reactions

Concrete Value Members

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

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    Definition Classes
    AnyRef → Any
  2. final def ##(): Int

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    Definition Classes
    AnyRef → Any
  3. def +(other: String): String

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    Implicit information
    This member is added by an implicit conversion from Events[T] to any2stringadd[Events[T]] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Events[T], B)

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    Implicit information
    This member is added by an implicit conversion from Events[T] to ArrowAssoc[Events[T]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean

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    Definition Classes
    AnyRef → Any
  6. def after[S](that: Events[S]): Events[T]

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    Creates a new event stream that produces events from this event stream only after that produces an event.

    Creates a new event stream that produces events from this event stream only after that produces an event.

    After that emits some event, all events from this are produced on the resulting event stream. If that unreacts before an event is produced on this, the resulting event\ stream unreacts. If this unreacts, the resulting event stream unreacts.

    S

    the type of that event stream

    that

    the event stream after whose first event the result can start propagating events

    returns

    the resulting event stream that emits only after that emits at least once

  7. final def asInstanceOf[T0]: T0

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    Definition Classes
    Any
  8. def batch(sz: Int): Events[Seq[T]]

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    Groups adjacent events together into batches.

    Groups adjacent events together into batches.

    Batches have the specified size, unless this unreacts before sufficiently many events are batched -- in this case, the last batch may have less events than what was specified.

    Note: at the moment, this operation is not specialized, and may incur some boxing when events are primitive elements.

    time       --------------------------------------->
    this       -----1---2---3------------4---5--|
    batch(3)   -------------[1, 2, 3]--------[4, 5]-|
    sz

    the size of each batch, must be greater than 0

    returns

    event stream with batches of adjacent events

  9. def clone(): AnyRef

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    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  10. def collect[S <: AnyRef](pf: PartialFunction[T, S])(implicit evidence: <:<[T, AnyRef]): Events[S]

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    Filters events from this event stream and maps them in the same time.

    Filters events from this event stream and maps them in the same time.

    The collect combinator uses a partial function pf to filter events from this event stream. Events for which the partial function is defined are mapped using the partial function, others are discarded.

    Note: This combinator is defined only for event streams that contain reference events. You cannot call it for event streams whose events are primitive values, such as Int. This is because the PartialFunction class is not itself specialized.

    S

    the type of the mapped event stream

    pf

    partial function used to filter and map events

    evidence

    evidence that T is a reference type

    returns

    an event stream with the partially mapped events

  11. def collectHint[W](pf: PartialFunction[Any, W]): Events[T]

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    Collects values from the event stream by applying a partial function, if possible.

  12. def concat[S](implicit evidence: <:<[T, Events[S]], a: Arrayable[S]): Events[S]

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    Concatenates the events produced by all the event streams emitted by this.

    Concatenates the events produced by all the event streams emitted by this.

    This operation is only available for event stream values that emit other event streams as events. Once this and all the event streams unreact, this event stream unreacts.

    Use case:

    def concat[S](): Events[S]

    Note: This operation potentially buffers events from the nested event streams. Unless each event stream emitted by this is known to unreact eventually, this operation should not be called.

    S

    the type of the events in event streams emitted by this

    evidence

    evidence that events of type T produced by this are actually event stream values of type S

    a

    evidence that arrays can be created for type S

    returns

    the event stream that concatenates all the events from nested event streams

  13. def concat(that: Events[T])(implicit a: Arrayable[T]): Events[T]

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    Creates a concatenation of this and that event stream.

    Creates a concatenation of this and that event stream.

    The resulting event stream produces all the events from this event stream until this unreacts, and then outputs all the events from that that happened before and after this unreacted. To do this, this operation potentially caches all the events from that. When that unreacts, the resulting event stream unreacts.

    Use case:

    def concat(that: Events[T]): Events[T]

    Note: This operation potentially caches events from that. Unless certain that this eventually unreacts, concat should not be used.

    that

    another event stream for the concatenation

    a

    evidence that arrays can be created for the type T

    returns

    event stream that concatenates events from this and that

  14. def count(implicit dummy: Spec[T]): Events[Int]

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    Emits the total number of events produced by this event stream.

    Emits the total number of events produced by this event stream.

    The returned value is a scala.reactive.Signal that holds the total number of emitted events.

    time  ---------------->
    this  ---x---y--z--|
    count ---1---2--3--|
    returns

    an event stream that emits the total number of events emitted since card was called

  15. def drop(n: Int): Events[T]

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    Drops n events from this event stream, and emits the rest.

    Drops n events from this event stream, and emits the rest.

    n

    number of events to drop

    returns

    event stream with the forwarded events

  16. def dropAfter(p: (T) ⇒ Boolean): Events[T]

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    Drop all events after an event that satisfies a predicate.

    Drop all events after an event that satisfies a predicate.

    This is similar to takeWhile, but includes the event that satisfies the predicate.

    time                ------------------------>
    this                -0---1--2--3-4--1-5--2-->
    dropAfter(_ == 4)       -1--2--3-4|
    p

    the predicate that specifies whether to drop subsequent events

    returns

    event stream with the forwarded events

  17. def dropWhile(p: (T) ⇒ Boolean): Events[T]

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    Returns a new event stream that forwards the events from this event stream as long as they satisfy the predicate p.

    Returns a new event stream that forwards the events from this event stream as long as they satisfy the predicate p.

    After an event that does not specify the predicate occurs, the resulting event stream unreacts.

    If the predicate throws an exception, the exceptions is propagated, and the resulting event stream unreacts.

    time             ------------------------>
    this             -0---1--2--3-4--1-5--2-->
    dropWhile(_ < 4)     ---------4--1-5--2-->
    p

    the predicate that specifies whether to take the element

    returns

    event stream with the forwarded events

  18. def ensuring(cond: (Events[T]) ⇒ Boolean, msg: ⇒ Any): Events[T]

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    Implicit information
    This member is added by an implicit conversion from Events[T] to Ensuring[Events[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  19. def ensuring(cond: (Events[T]) ⇒ Boolean): Events[T]

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    Implicit information
    This member is added by an implicit conversion from Events[T] to Ensuring[Events[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  20. def ensuring(cond: Boolean, msg: ⇒ Any): Events[T]

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    Implicit information
    This member is added by an implicit conversion from Events[T] to Ensuring[Events[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  21. def ensuring(cond: Boolean): Events[T]

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    Implicit information
    This member is added by an implicit conversion from Events[T] to Ensuring[Events[T]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  22. final def eq(arg0: AnyRef): Boolean

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    Definition Classes
    AnyRef
  23. def equals(arg0: Any): Boolean

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    Definition Classes
    AnyRef → Any
  24. def filter(p: (T) ⇒ Boolean): Events[T]

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    Filters events from this event stream value using a specified predicate p.

    Filters events from this event stream value using a specified predicate p.

    Only events from this for which p returns true are emitted on the resulting event stream.

    p

    the predicate used to filter events

    returns

    an event streams with the filtered events

  25. def finalize(): Unit

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    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  26. def first[S](implicit evidence: <:<[T, Events[S]]): Events[S]

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    Returns an event stream that forwards from the first active nested event stream.

    Returns an event stream that forwards from the first active nested event stream.

    Regardless of the order in which the nested event streams were emitted, only the nested event stream that is the first to emit an event gets chosen.

    This is illustrated in the following, where the second event stream in this is the first to emit an event.

    time   --------------------------->
    this       ------4--7---11-------->
                 --1------2-----3----->
                     --------0---5---->
    first  --------1------1-----3----->
    S

    the type of the events in event stream emitted by this

    evidence

    evidence that events of type T produced by this are actually event streams of type S

    returns

    event stream that concatenates all the events from nested event streams

  27. def formatted(fmtstr: String): String

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    Implicit information
    This member is added by an implicit conversion from Events[T] to StringFormat[Events[T]] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  28. def get: T

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    Returns the first event emitted by this event stream.

    Returns the first event emitted by this event stream.

    This method will return immediately and will not block.

    This method will return a value only if this event stream emits one or more values on subscription. Otherwise, this method throws a NoSuchElementException.

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

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    Definition Classes
    AnyRef → Any
  30. def groupBy[K](f: (T) ⇒ K): Events[(K, Events[T])]

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    Returns an event stream that groups events into event stream using a function.

    Returns an event stream that groups events into event stream using a function.

    For each unique key returned by the specified function f, the resulting event stream emits a pair with the key and the event stream of values that map to that key. The resulting event stream unreacts when this event stream unreacts. The nested event streams also unreact when this event stream unreacts.

    time            ----------------------------->
    this            ---3-------5----4------7--8-->
    groupBy(_ % 2)     (1, 3---5-----------7----->)
                                    (0, 4-----8-->)
    K

    the type of the keys according to which events are grouped

    f

    the grouping function for the events

    returns

    event stream that emits keys and associated event streams

  31. def hashCode(): Int

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    Definition Classes
    AnyRef → Any
  32. def ignoreExceptions: Events[T]

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    Returns an event stream that ignores all exceptions in this event stream.

    Returns an event stream that ignores all exceptions in this event stream.

    returns

    an event stream that forwards all events, and ignores all exceptions

  33. def incremental[S](state: ⇒ (Subscription, (Observer[S]) ⇒ Unit))(implicit s: Spec[S]): Events[S]

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    Incrementally computes state, and emits events to an observer.

    Incrementally computes state, and emits events to an observer.

    Creates an incrementally updated state, and uses it to emit events to an observer whenever this event stream emits an event.

    S

    type of the output events

    state

    function that creates some incrementally computed state, and returns a tuple of the subscription for that state, and the function that emits events from this state

    returns

    an event stream that emits a sampled view of the state whenever this event stream emits an event

  34. final def isInstanceOf[T0]: Boolean

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    Definition Classes
    Any
  35. def liftTry: Events[Try[T]]

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    Converts an event stream of Events[T] to type Events[Try[T]].

    Converts an event stream of Events[T] to type Events[Try[T]].

    Inbound exceptions are lifted into Failure events, while normal events are converted into Success events.

  36. def map[S](f: (T) ⇒ S): Events[S]

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    Returns a new stream that maps events from this stream using the function f.

    Returns a new stream that maps events from this stream using the function f.

    time    --------------------->
    this    --e1------e2------|
    mapped  --f(e1)---f(e2)---|
    S

    the type of the mapped events

    f

    the mapping function

    returns

    event stream value with the mapped events

  37. def mutate[M1 >: Null <: AnyRef, M2 >: Null <: AnyRef, M3 >: Null <: AnyRef](m1: Mutable[M1], m2: Mutable[M2], m3: Mutable[M3])(f: (M1, M2, M3) ⇒ (T) ⇒ Unit)(implicit dummy: Spec[T]): Subscription

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    Mutates multiple mutable event stream values m1, m2 and m3 each time that this event stream produces an event.

    Mutates multiple mutable event stream values m1, m2 and m3 each time that this event stream produces an event.

    Note that the objects m1, m2 and m3 are mutated simultaneously, and events are propagated after the mutation ends. This version of the mutate works on multiple event streams.

    M1

    the type of the first mutable event stream

    M2

    the type of the second mutable event stream

    M3

    the type of the third mutable event stream

    m1

    the first mutable stream

    m2

    the second mutable stream

    m3

    the second mutable stream

    f

    the function that modifies the mutables

    returns

    a subscription used to cancel this mutation

  38. def mutate[M1 >: Null <: AnyRef, M2 >: Null <: AnyRef](m1: Mutable[M1], m2: Mutable[M2])(f: (M1, M2) ⇒ (T) ⇒ Unit): Subscription

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    Mutates multiple mutable event stream values m1 and m2 each time that this event stream produces an event.

    Mutates multiple mutable event stream values m1 and m2 each time that this event stream produces an event.

    Note that the objects m1 and m2 are mutated simultaneously, and events are propagated after the mutation ends. This version of the mutate works on multiple event streams.

    M1

    the type of the first mutable event stream

    M2

    the type of the second mutable event stream

    m1

    the first mutable stream

    m2

    the second mutable stream

    f

    the function that modifies the mutables

    returns

    a subscription used to cancel this mutation

  39. def mutate[M >: Null <: AnyRef](m: Mutable[M])(f: (M) ⇒ (T) ⇒ Unit): Subscription

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    Mutates the target mutable event stream called mutable each time this event stream produces an event.

    Mutates the target mutable event stream called mutable each time this event stream produces an event.

    Here is an example, given an event stream of type r:

    val eventLog = new Events.Mutable(mutable.Buffer[String]())
    val eventLogMutations = r.mutate(eventLog) { buffer => event =>
      buffer += "at " + System.nanoTime + ": " + event
    } // <-- eventLog event propagated

    Whenever an event arrives on r, an entry is added to the buffer underlying eventLog. After the mutation completes, a modification event is produced by the eventLog and can be used subsequently:

    val uiUpdates = eventLog onEvent { b =>
      eventListWidget.add(b.last)
    }

    Note: No two events will ever be concurrently processed by different threads on the same event stream mutable, but an event that is propagated from within the mutation can trigger an event on this. The result is that mutation is invoked concurrently on the same thread. The following code is problematic has a feedback loop in the dataflow graph:

    val emitter = new Events.Emitter[Int]
    val mutable = new Events.Mutable[mutable.Buffer[Int]()]
    emitter.mutate(mutable) { buffer => n =>
      buffer += n
      if (n == 0)
        emitter.react(n + 1) // <-- event propagated
      assert(buffer.last == n)
    }
    emitter.react(0)

    The statement emitter.react(n + 1) in the mutate block suspends the current mutation, calls the mutation recursively and changes the value of cell, and the assertion fails when the first mutation resumes.

    Care must be taken to avoid f from emitting events in feedback loops.

    M

    the type of the event stream mutable value

    m

    the target mutable stream to be mutated with events from this stream

    f

    the function that modifies mutable given an event of type T

    returns

    a subscription used to cancel this mutation

  40. def mux[S](implicit evidence: <:<[T, Events[S]], ds: Spec[S]): Events[S]

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    Returns events from the last event stream that this emitted as an event of its own, in effect multiplexing the nested reactives.

    Returns events from the last event stream that this emitted as an event of its own, in effect multiplexing the nested reactives.

    The resulting event stream only emits events from the event stream last emitted by this, the preceding event streams are ignored.

    This combinator is only available if this event stream emits events that are themselves event streams.

    Example:

    val currentEvents = new Events.Emitter[Events[Int]]
    val e1 = new Events.Emitter[Int]
    val e2 = new Events.Emitter[Int]
    val currentEvent = currentEvents.mux()
    val prints = currentEvent.onEvent(println)
    
    currentEvents.react(e1)
    e2.react(1) // nothing is printed
    e1.react(2) // 2 is printed
    currentEvents.react(e2)
    e2.react(6) // 6 is printed
    e1.react(7) // nothing is printed

    Shown on the diagram:

    time            ------------------->
    currentEvents   --e1------e2------->
    e1              --------2----6----->
    e2              -----1----------7-->
    currentEvent    --------2----6----->

    Use case:

    def mux[S](): Events[S]
    S

    the type of the events in the nested event stream

    evidence

    an implicit evidence that this event stream is nested -- it emits events of type T that is actually an Events[S]

    returns

    event stream of events from the event stream last emitted by this

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

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    Definition Classes
    AnyRef
  42. final def notify(): Unit

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    Definition Classes
    AnyRef
  43. final def notifyAll(): Unit

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    Definition Classes
    AnyRef
  44. def on(observer: ⇒ Unit)(implicit dummy: Spec[T]): Subscription

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    Registers a callback for react events, disregarding their values

    Registers a callback for react events, disregarding their values

    A shorthand for onReaction -- called whenever an event occurs.

    This method is handy when the precise event value is not important, or the type of the event is Unit.

    observer

    the callback invoked when an event arrives

    returns

    a subscription for unsubscribing from reactions

  45. def onDone(observer: ⇒ Unit)(implicit dummy: Spec[T]): Subscription

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    Executes the specified block when this event stream unreacts.

    Executes the specified block when this event stream unreacts.

    observer

    the callback invoked when this unreacts

    returns

    a subscription for the unreaction notification

  46. def onEvent(observer: (T) ⇒ Unit): Subscription

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    Registers callback for react events.

    Registers callback for react events.

    A shorthand for onReaction -- the specified function is invoked whenever there is an event.

    observer

    the callback for events

    returns

    a subcriptions for unsubscribing from reactions

  47. def onEventOrDone(reactFunc: (T) ⇒ Unit)(unreactFunc: ⇒ Unit): Subscription

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    Registers callbacks for react and unreact events.

    Registers callbacks for react and unreact events.

    A shorthand for onReaction -- the specified functions are invoked whenever there is an event or an unreaction.

    reactFunc

    called when this event stream produces an event

    unreactFunc

    called when this event stream unreacts

    returns

    a subscription for unsubscribing from reactions

  48. def onExcept(pf: PartialFunction[Throwable, Unit]): Subscription

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    Executes the specified block when this event stream forwards an exception.

    Executes the specified block when this event stream forwards an exception.

    pf

    the partial function used to handle the exception

    returns

    a subscription for the exception notifications

  49. def onMatch(observer: PartialFunction[T, Unit])(implicit sub: <:<[T, AnyRef]): Subscription

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    Registers callback for events that match the specified patterns.

    Registers callback for events that match the specified patterns.

    A shorthand for onReaction -- the specified partial function is applied to only those events for which it is defined.

    This method only works for AnyRef values.

    Example:

    r onMatch {
      case s: String => println(s)
      case n: Int    => println("number " + s)
    }

    Use case:

    def onMatch(reactor: PartialFunction[T, Unit]): Subscription
    observer

    the callback for those events for which it is defined

    returns

    a subscription for unsubscribing from reactions

  50. def once: Events[T]

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    Creates an event stream that forwards an event from this event stream only once.

    Creates an event stream that forwards an event from this event stream only once.

    The resulting event stream emits only a single event produced by this event stream after once is called, and then unreacts.

    time ----------------->
    this --1-----2----3--->
    once      ---2|
    returns

    an event stream with the first event from this

  51. def pipe(ch: Channel[T]): Subscription

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    Pipes the events on this input stream to the target channel.

    Pipes the events on this input stream to the target channel.

    Exceptions are ignored.

  52. def possibly(probability: Double): Events[T]

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    Forwards an event from this event stream with some probability.

    Forwards an event from this event stream with some probability.

    The probability is specified as a real value from 0.0 to 1.0.

    probability

    the probability to forward an event

    returns

    the event stream that forwards events with some probability

  53. def recover[U >: T](pf: PartialFunction[Throwable, U])(implicit evid: <:<[U, AnyRef]): Events[U]

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    Transforms emitted exceptions into an event stream.

    Transforms emitted exceptions into an event stream.

    If the specified partial function is defined for the exception, an event is emitted. Otherwise, the same exception is forwarded.

    U

    type of events exceptions are mapped to

    pf

    partial mapping from functions to events

    returns

    an event stream that emits events when an exception arrives

  54. def reducePast[S](z: S)(op: (S, T) ⇒ S): Events[S]

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    Reduces all the events in this event stream.

    Reduces all the events in this event stream.

    Emits a single event *after* the event stream unreacts, and then it unreacts itself. For example, the event stream this.reducePast(0)(_ + _) graphically:

    time       ----------------->
    this       --1-----2----3-|
    reducePast ---------------6|
    S

    the type of the events in the resulting event stream

    z

    the initial value of the reduce past

    op

    the operator that combines the last event and the current one

    returns

    an event stream that emits the reduction of all events once

  55. def sample[S](f: ⇒ S): Events[S]

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    Whenever this stream emits, uses the sampling function to emit another event.

    Whenever this stream emits, uses the sampling function to emit another event.

    This combinator is useful when there is a clear ordering of events in different event stream, and the incremental system state needs to be sampled at specific points in time. The sampling function is guaranteed to be called only once per each emitted event (however, if there are multiple subscribers to the resulting event stream, then the sampling function will be called once for each subscriber).

    S

    the type of the sampled events

    f

    the sampling function

    returns

    event stream value with the sampled events

  56. def scanPast[S](z: S)(op: (S, T) ⇒ S): Events[S]

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    Creates a new event stream s that produces events by consecutively applying the specified operator op to the previous event that s produced and the current event that this event stream value produced.

    Creates a new event stream s that produces events by consecutively applying the specified operator op to the previous event that s produced and the current event that this event stream value produced.

    The scanPast operation allows the current event from this event stream to be mapped into a different event by looking "into the past", i.e. at the event previously emitted by the resulting event stream.

    Example -- assume that an event stream r produces events 1, 2 and 3. The following s:

    val s = r.scanPast(0)((sum, n) => sum + n)

    will produce events 1, 3 (1 + 2) and 6 (3 + 3). Note: the initial value 0 is not emitted. Shown graphically:

    time     ----------------->
    this     --1-----2----3--->
    scanPast --1-----3----6--->|

    The scanPast can also be used to produce an event stream of a different type. The following produces a complete history of all the events seen so far:

    val s2 = r.scanPast(List[Int]()) {
      (history, n) => n :: history
    }

    The s2 will produce events 1 :: Nil, 2 :: 1 :: Nil and 3 :: 2 :: 1 :: Nil. Note: the initial value Nil is not emitted.

    This operation is closely related to a scanLeft on a collection -- if an event stream were a sequence of elements, then scanLeft would produce a new sequence whose elements correspond to the events of the resulting event stream.

    S

    the type of the events in the resulting event stream

    z

    the initial value of the scan past

    op

    the operator the combines the last produced and the current event into a new one

    returns

    an event stream that scans events from this event stream

  57. def sliding(sz: Int)(implicit s: Spec[T]): Events[Queue[T]]

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    Creates a sliding window of the events produced in this event stream.

    Creates a sliding window of the events produced in this event stream.

    time       ------------------------------------------->
    this       -----1----2------3----------4---------|
    batch(3)   -----[1]--[2,1]--[3,2,1]----[4,3,2]---|

    Note: whenever an event arrives, the sliding window must be updated. The sliding window is represented with an immutable queue data structure. This data structure is used to incrementally a new version of the sliding window. The update operation takes O(1) time, but needs to allocate around 7 objects on average. That is generally not very expensive, but clients that really need top performance should use mutate with a mutable queue data structure to maintain the sliding window.

    The resulting Conc.Queue has O(log n) access to elements, where n is the size of the sliding window. It be converted to an array in O(n) time.

    sz

    size of the sliding window

    returns

    the sliding window data structure

  58. def sync[S, R](that: Events[S])(f: (T, S) ⇒ R)(implicit at: Arrayable[T], as: Arrayable[S]): Events[R]

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    Syncs the arrival of events from this and that event stream.

    Syncs the arrival of events from this and that event stream.

    Ensures that pairs of events from this event stream and that event stream are emitted together. If the events produced in time by this and that, the sync will be as follows:

    time   --------------------------->
    this   ----1---------2-------4---->
    that   --1-----2--3--------------->
    sync   ----1,1-------2,2-----4,3-->

    Pairs of events produced from this and that are then transformed using specified function f. For example, clients that want to output tuples do:

    val synced = (a sync b) { (a, b) => (a, b) }

    Clients that, for example, want to create differences in pairs of events do:

    val diffs = (a sync b)(_ - _)

    The resulting event stream unreacts either when this unreacts and there are no more buffered events from this, or when that unreacts and there are no more buffered events from that.

    Use case:

    def sync[S, R](that: Events[S])(f: (T, S) => R): Events[R]

    Note: This operation potentially caches events from this and that. Unless certain that both this produces a bounded number of events before the that produces an event, and vice versa, this operation should not be called.

    S

    the type of the events in that event stream

    R

    the type of the events in the resulting event stream

    that

    the event stream to sync with

    f

    the mapping function for the pair of events

    at

    evidence that arrays can be created for the type T

    as

    evidence that arrays can be created for the type S

    returns

    the event stream with the resulting events

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

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    Definition Classes
    AnyRef
  60. def tail: Events[T]

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    Emits all the events from this even stream except the first one.

    Emits all the events from this even stream except the first one.

    returns

    event stream with the forwarded events

  61. def take(n: Int): Events[T]

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    Takes n events from this event stream, and unreacts.

    Takes n events from this event stream, and unreacts.

    n

    number of events to take

    returns

    event stream with the forwarded events

  62. def takeWhile(p: (T) ⇒ Boolean): Events[T]

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    Returns a new event stream that forwards the events from this event stream as long as they satisfy the predicate p.

    Returns a new event stream that forwards the events from this event stream as long as they satisfy the predicate p.

    After an event that does not specify the predicate occurs, the resulting event stream unreacts.

    If the predicate throws an exception, the exceptions is propagated, and the resulting event stream unreacts.

    time             ------------------------>
    this             -0---1--2--3-4--1-5--2-->
    takeWhile(_ < 4)     -1--2--3-|
    p

    the predicate that specifies whether to take the element

    returns

    event stream with the forwarded events

  63. def toCold(init: T): Signal[T]

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    Given an initial event init, converts the event stream into a cold Signal.

    Given an initial event init, converts the event stream into a cold Signal.

    Cold signals emit events only when some observer is subscribed to them. As soon as there are no subscribers for the signal, the signal unsubscribes itself from its source event stream. While unsubscribed, the signal **does not update its value**, even if its event source (this event stream) emits events.

    If there is at least one subscription to the cold signal, the signal subscribes itself to its event source (this event stream) again.

    The unsubscribe method on the resulting signal does nothing -- the subscription of the cold signal unsubscribes only after all of the subscribers unsubscribe, or the source event stream unreacts.

  64. def toEager: Signal[T]

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    Same as toEmpty, but emits an event on subscription if signal is non-empty.

  65. def toEmpty: Signal[T]

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    Converts this event stream into a Signal.

    Converts this event stream into a Signal.

    The resulting signal initially does not contain an event, and subsequently contains any event that this event stream produces.

    returns

    the signal version of the current event stream

  66. def toIVar: IVar[T]

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    Creates an IVar event stream value, completed with the first event from this event stream.

    Creates an IVar event stream value, completed with the first event from this event stream.

    After the IVar is assigned, all subsequent events are ignored. If the self event stream is unreacted before any event arrives, the IVar is closed.

    returns

    an IVar with the first event from this event stream

  67. def toRCell: RCell[T]

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    Creates an initially empty RCell, updated with events of this event stream.

    Creates an initially empty RCell, updated with events of this event stream.

    After the first event gets produced, the RCell is assigned this value, and is from there on not empty. The RCell can also, alternatively, be modified by clients.

    returns

    an RCell with the first event from this event stream

  68. def toSignal(init: T): Signal[T]

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    Given an initial event init, converts this event stream into a Signal.

    Given an initial event init, converts this event stream into a Signal.

    The resulting signal initially contains the event init, and subsequently any event that this event stream produces.

    init

    an initial value for the signal

    returns

    the signal version of the current event stream

  69. def toString(): String

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    Definition Classes
    AnyRef → Any
  70. def union[S](implicit evidence: <:<[T, Events[S]], ds: Spec[S]): Events[S]

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    Unifies the events produced by all the event streams emitted by this.

    Unifies the events produced by all the event streams emitted by this.

    This operation is only available for event stream values that emit other event streams as events. The resulting event stream unifies events of all the event streams emitted by this. Once this and all the event streams emitted by this unreact, the resulting event stream terminates.

    Note: if the same event stream is emitted multiple times, it will be subscribed to multiple times.

    Example:

    time  -------------------------->
    this     --1----2--------3------>
                 ---------5----6---->
                   ---4----------7-->
    union -----1----2-4---5--3-6-7-->

    Use case:

    def union[S](): Events[S]
    S

    the type of the events in event streams emitted by this

    evidence

    evidence that events of type T produced by this are actually event stream values of type S

    returns

    the event stream with the union of all the events from the nested event streams

  71. def union(that: Events[T]): Events[T]

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    Creates a union of this and that event stream.

    Creates a union of this and that event stream.

    The resulting event stream emits events from both this and that event stream. It unreacts when both this and that event stream unreact.

    that

    another event stream for the union

    returns

    the event stream with unified events from this and that

  72. def unliftTry[S](implicit evid: <:<[T, Try[S]]): Events[S]

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    Converts an event stream of Events[Try[S]] to type Events[S].

    Converts an event stream of Events[Try[S]] to type Events[S].

    Normal events are emitted for Success objects, and exceptions for Failure.

  73. def unreacted(implicit ds: Spec[T]): Events[Unit]

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    Returns a new event stream that emits an event when this event stream unreacts.

    Returns a new event stream that emits an event when this event stream unreacts.

    After the current event stream unreacts, the result event stream first emits an event of type Unit, and then unreacts itself.

    Exceptions from this event stream are propagated until the resulting event stream unreacts -- after that, this event stream is not allowed to produce exceptions.

    Shown on the diagram:

    time            ------------------->
    this            --1--2-----3-|
    currentEvent    -------------()-|
    returns

    the unreaction event stream and subscription

  74. def until[S](that: Events[S]): Events[T]

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    Creates a new event stream value that produces events from this event stream value until that produces an event.

    Creates a new event stream value that produces events from this event stream value until that produces an event.

    If this unreacts before that produces a value, the resulting event stream unreacts. Otherwise, the resulting event stream unreacts whenever that produces a value.

    S

    the type of that event stream

    that

    the event stream until whose first event the result propagates events

    returns

    the resulting event stream that emits only until that emits

  75. final def wait(): Unit

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    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  76. final def wait(arg0: Long, arg1: Int): Unit

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    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  77. final def wait(arg0: Long): Unit

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    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  78. def zipHint[S](f: (T, Any) ⇒ S): Events[S]

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    Zips values from this event stream with the hint value.

  79. def [B](y: B): (Events[T], B)

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    Implicit information
    This member is added by an implicit conversion from Events[T] to ArrowAssoc[Events[T]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from Events[T] to any2stringadd[Events[T]]

Inherited by implicit conversion StringFormat from Events[T] to StringFormat[Events[T]]

Inherited by implicit conversion Ensuring from Events[T] to Ensuring[Events[T]]

Inherited by implicit conversion ArrowAssoc from Events[T] to ArrowAssoc[Events[T]]

Ungrouped