org.springframework.cloud.stream.reactive

Annotation Type StreamEmitter

@Target(value={METHOD,ANNOTATION_TYPE})
 @Retention(value=RUNTIME)
 @Documented
public @interface StreamEmitter

Method level annotation that marks a method to be an emitter to outputs declared via EnableBinding (e.g. channels). This annotation is intended to be used in a Spring Cloud Stream application that requires a source to write to one or more Outputs using the reactive paradigm. No Inputs are allowed on a method that is annotated with StreamEmitter. Depending on how the method is structured, there are some flexibility in how the Output may be used. Here are some supported usage patterns: A StreamEmitter method that has a return type cannot take any method parameters.

 @StreamEmitter
 @Output(Source.OUTPUT)
 public Flux<String> emit() {
        return Flux.intervalMillis(1000)
                .map(l -> "Hello World!!");
 }
 

The following examples show how a void return type can be used on a method with StreamEmitter and how the method signatures could be used in a flexible manner.

 @StreamEmitter
 public void emit(@Output(Source.OUTPUT) FluxSender output) {
        output.send(Flux.intervalMillis(1000)
                .map(l -> "Hello World!!"));
 }
 

 @StreamEmitter
 @Output(Source.OUTPUT)
 public void emit(FluxSender output) {
        output.send(Flux.intervalMillis(1000)
                .map(l -> "Hello World!!"));
 }
 

 @StreamEmitter
 public void emit(@Output("OUTPUT1") FluxSender output1,
                                        @Output("OUTPUT2") FluxSender output2,
                                        @Output("OUTPUT3)" FluxSender output3) {
        output1.send(Flux.intervalMillis(1000)
                .map(l -> "Hello World!!"));
        output2.send(Flux.intervalMillis(1000)
                .map(l -> "Hello World!!"));
        output3.send(Flux.intervalMillis(1000)
                .map(l -> "Hello World!!"));
        }

Since:

1.3.0

Author:

Soby Chacko