Module javafx.base
Package javafx.util

Interface Subscription

Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public interface Subscription
Represents a cancel or cleanup operation for an action that can be cancelled or that allocated resources. Subscriptions can be obtained, for example, as a result of registering a callback, starting a timer, or allocating resources. They provide a convenient way for subscribers to cancel these actions at a later time, without requiring additional information or even access to the source from where they were originally obtained. 
 class Publisher {
   public Subscription subscribe(Consumer<NewsLetter> subscriber) {
     register(subscriber);

     // return a Subscription which unregisters the original subscriber
     return () -> unregister(subscriber);
   }
 }

Subscriptions can also be combined using combine(javafx.util.Subscription...) and and(javafx.util.Subscription), which allows for multiple subscriptions to be unsubscribed together. This is useful when they share the same lifecycle, for example, when performing cleanup for the same object.

Since:
21

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final Subscription
    EMPTY
    An empty subscription.

  • Method Summary

    Modifier and Type
    Method
    Description
    default Subscription
    and(Subscription other)
    Combines this Subscription with the given Subscription and returns a new Subscription which will cancel both when cancelled.
    static Subscription
    combine(Subscription... subscriptions)
    Returns a Subscription which combines all of the given subscriptions.
    void
    unsubscribe()
    Cancels this subscription, or does nothing if already cancelled.

  • Field Details

    • EMPTY

      static final Subscription EMPTY
      An empty subscription. Does nothing when cancelled.

  • Method Details

    • combine

      static Subscription combine(Subscription... subscriptions)
      Returns a Subscription which combines all of the given subscriptions.
      Parameters:
      subscriptions - an array of subscriptions to combine, cannot be null or contain null
      Returns:
      a Subscription, never null
      Throws:
      NullPointerException - when subscriptions is null or contains null

    • unsubscribe

      void unsubscribe()
      Cancels this subscription, or does nothing if already cancelled.

      Implementation Requirements:
      Implementors must ensure the implementation is idempotent (a no-op if called more than once).

    • and

      default Subscription and(Subscription other)
      Combines this Subscription with the given Subscription and returns a new Subscription which will cancel both when cancelled.

      This is equivalent to Subscription.combine(this, other).

      Parameters:
      other - another Subscription, cannot be null
      Returns:
      a combined Subscription which will cancel both when cancelled, never null
      Throws:
      NullPointerException - when other is null