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