Class Subject<T>

java.lang.Object
nl.colorize.util.Subject<T>
Type Parameters:
T - The type of event that can be subscribed to.
All Implemented Interfaces:
Flow.Publisher<T>
public final class Subject<T> extends Object implements Flow.Publisher<T>
Publishes (possibly asynchronous) events to registered subscribers. This class provides an implementation of a publisher in the Flow API. It can be used on all platforms supported by this library, including TeaVM.

Subject instances are thread-safe and can be accessed from different threads. This facilitates workflows where publishers and subscribers operate on different threads.

  • Constructor Details

    • Subject

      public Subject()

  • Method Details

    • next

      public void next(T event)
      Publishes the next event to all event subscribers. This method does nothing if this Subject has already been marked as completed.

    • nextError

      public void nextError(Throwable error)
      Publishes the next error to all error subscribers. If no error subscribers have been registered, this will invoke the default error handler that will print a log messsage describing the unhandled error. This method does nothing if this Subject has already been marked as completed.

    • next

      public void next(Callable<T> operation)
      Performs the specified operation and publishes the resulting event to subscribers. If the operation completes normally, the return value is published to subscribers as an event. If an exception occurs during the operation, this exception is published to error subscribers. Does nothing if this Subject has already been marked as completed.

    • subscribe

      public void subscribe(Flow.Subscriber<? super T> subscriber)
      Registers the specified subscriber to receive published events and errors. If there are currently undelivered events or errors, the new subscriber will immediately be notified of them.
      Specified by:
      subscribe in interface Flow.Publisher<T>

    • subscribe

      public Flow.Subscription subscribe(Consumer<T> onEvent, Consumer<Throwable> onError, Runnable onComplete)
      Registers a subscriber that will invoke the specified callback functions on events, errors, and completion, respectively. The new subscriber will immediately be notified of any undelivered events.
      Returns:
      A Flow.Subscription for the registered subscriber.

    • subscribe

      public Flow.Subscription subscribe(Consumer<T> onEvent, Consumer<Throwable> onError)
      Registers a subscriber that will invoke the specified callback functions on events and errors, respectively. The new subscriber will immediately be notified of any undelivered events.
      Returns:
      A Flow.Subscription for the registered subscriber.

    • subscribe

      public Flow.Subscription subscribe(Consumer<T> onEvent)
      Registers a subscriber that will invoke the specified callback functions on events. The new subscriber will immediately be notified of any undelivered events.
      Returns:
      A Flow.Subscription for the registered subscriber.

    • subscribeErrors

      public Flow.Subscription subscribeErrors(Consumer<Throwable> onError)
      Registers a subscriber that will invoke the specified callback functions on errors. The new subscriber will immediately be notified of any undelivered errors.
      Returns:
      A Flow.Subscription for the registered subscriber.

    • subscribe

      public Flow.Subscription subscribe(Subject<T> subscriber)
      Subscribes the specified other Subject to listen for both events and errors generated by this Subject. This effectively means that events published by this instance will be forwarded to subscriber's subscribers.
      Returns:
      A Flow.Subscription for the registered subscriber.

    • complete

      public void complete()
      Marks this Subject as completed, meaning that no new events or errors will be published to subscribers.

    • map

      public <S> Subject<S> map(Function<T,S> mapper)
      Returns a Subject that forwards events to its own subscribers, first applying the specified mapper function to each event. Intended as the equivalent of Stream.map(Function) for asynchronous events.

    • flatMap

      public <S> Subject<S> flatMap(Function<T, Stream<S>> mapper)
      Returns a Subject that forwards events to its own subscribers, first applying the specified mapper function to each event. Intended as the equivalent of Stream.flatMap(Function) for asynchronous events.

    • filter

      public Subject<T> filter(Predicate<T> predicate)
      Returns a Subject that forwards events to its own subscribers, though only events that match the specified predicate. Intended as the equivalent of Stream.filter(Predicate) for asynchronous events.

    • of

      @SafeVarargs public static <T> Subject<T> of(T... values)
      Creates a Subject that will immediately publish the specified values to its subscribers.

    • of

      public static <T> Subject<T> of(Iterable<T> values)
      Creates a Subject that will immediately publish the specified values to its subscribers.

    • run

      public static <T> Subject<T> run(Callable<T> operation)
      Performs the specified operation in the current thread, returns a Subject that can be used to subscribe to its results.

    • runAsync

      public static <T> Subject<T> runAsync(Callable<T> operation)
      Performs the specified operation in a new thread, returns a Subject that can be used to subscribe to its results.