Sinks (Reactor Core 3.5.21 API)

java.lang.Object
- reactor.core.publisher.Sinks

```
public final class Sinks
extends Object
```
Sinks are constructs through which Reactive Streams signals can be programmatically pushed, with Flux or Mono semantics. These standalone sinks expose tryEmit methods that return an Sinks.EmitResult enum, allowing to atomically fail in case the attempted signal is inconsistent with the spec and/or the state of the sink.
This class exposes a collection of (Sinks.Many builders and Sinks.One factories. Unless constructed through the unsafe() spec, these sinks are thread safe in the sense that they will detect concurrent access and fail fast on one of the attempts. unsafe() sinks on the other hand are expected to be externally synchronized (typically by being called from within a Reactive Streams-compliant context, like a Subscriber or an operator, which means it is ok to remove the overhead of detecting concurrent access from the sink itself).

Author:

Simon Baslé, Stephane Maldini

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`Sinks.EmissionException` An exception representing a `failed` `Sinks.EmitResult`.
`static interface`	`Sinks.EmitFailureHandler` A handler supporting the emit API (eg.
`static class`	`Sinks.EmitResult` Represents the immediate result of an emit attempt (eg.
`static interface`	`Sinks.Empty<T>` A base interface for standalone `Sinks` with complete-or-fail semantics.
`static interface`	`Sinks.Many<T>` A base interface for standalone `Sinks` with `Flux` semantics.
`static interface`	`Sinks.ManySpec` Provides `Sinks.Many` specs for sinks which can emit multiple elements
`static interface`	`Sinks.ManyWithUpstream<T>` A `Sinks.Many` which additionally allows being subscribed to an upstream `Publisher`, which is an advanced pattern requiring external synchronization.
`static interface`	`Sinks.ManyWithUpstreamUnsafeSpec` Instead of `unsafe` flavors of `Sinks.Many`, this spec provides `Sinks.ManyWithUpstream` implementations.
`static interface`	`Sinks.MulticastReplaySpec` Provides multicast with history/replay capacity : 1 sink, N `Subscriber`
`static interface`	`Sinks.MulticastSpec` Provides multicast : 1 sink, N `Subscriber`
`static interface`	`Sinks.One<T>` A base interface for standalone `Sinks` with `Mono` semantics.
`static interface`	`Sinks.RootSpec` Provides a choice of `Sinks.One`/`Sinks.Empty` factories and `further specs` for `Sinks.Many`.
`static interface`	`Sinks.UnicastSpec` Provides unicast: 1 sink, 1 `Subscriber`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static <T> Sinks.Empty<T>`	`empty()` A `Sinks.Empty` which exclusively produces one terminal signal: error or complete.
`static Sinks.ManySpec`	`many()` Help building `Sinks.Many` sinks that will broadcast multiple signals to one or more `Subscriber`.
`static <T> Sinks.One<T>`	`one()` A `Sinks.One` that works like a conceptual promise: it can be completed with or without a value at any time, but only once.
`static Sinks.RootSpec`	`unsafe()` Return a `root spec` for more advanced use cases such as building operators.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - empty
```
public static <T> Sinks.Empty<T> empty()
```
    A Sinks.Empty which exclusively produces one terminal signal: error or complete. It has the following characteristics:
    - Multicast
    - Backpressure : this sink does not need any demand since it can only signal error or completion
    - Replaying: Replay the terminal signal (error or complete).
    Use Sinks.Empty.asMono() to expose the Mono view of the sink to downstream consumers.
    Returns:
    
    a new Sinks.Empty
    
    See Also:
    
    Sinks.RootSpec.empty()
  - one
```
public static <T> Sinks.One<T> one()
```
    A Sinks.One that works like a conceptual promise: it can be completed with or without a value at any time, but only once. This completion is replayed to late subscribers. Calling Sinks.One.tryEmitValue(Object) (or Sinks.One.emitValue(Object, Sinks.EmitFailureHandler)) is enough and will implicitly produce a Subscriber.onComplete() signal as well.
    Use Sinks.Empty.asMono() to expose the Mono view of the sink to downstream consumers.
    
    Returns:
    
    a new Sinks.One
    
    See Also:
    
    Sinks.RootSpec.one()
  - many
```
public static Sinks.ManySpec many()
```
    Help building Sinks.Many sinks that will broadcast multiple signals to one or more Subscriber.
    Use Sinks.Many.asFlux() to expose the Flux view of the sink to the downstream consumers.
    
    Returns:
    
    Sinks.ManySpec
    
    See Also:
    
    Sinks.RootSpec.many()
  - unsafe
```
public static Sinks.RootSpec unsafe()
```
    Return a root spec for more advanced use cases such as building operators. Unsafe Sinks.Many, Sinks.One and Sinks.Empty are not serialized nor thread safe, which implies they MUST be externally synchronized so as to respect the Reactive Streams specification. This can typically be the case when the sinks are being called from within a Reactive Streams-compliant context, like a Subscriber or an operator. In turn, this allows the sinks to have less overhead, since they don't care to detect concurrent access anymore.
    
    Returns:
    
    Sinks.RootSpec

Class Sinks

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

empty

one

many

unsafe