rx

Interface Producer

public interface Producer

Interface that establishes a request-channel between an Observable and a Subscriber and allows the Subscriber to request a certain amount of items from the Observable (otherwise known as backpressure).

The request amount only affects calls to Observer.onNext(Object); onError and onCompleted may appear without requests.

However, backpressure is somewhat optional in RxJava 1.x and Subscribers may not receive a Producer via their Subscriber.setProducer(Producer) method and will run in unbounded mode. Depending on the chain of operators, this can lead to MissingBackpressureException.

Method Summary

Modifier and Type	Method and Description
void	request(long n) Request a certain maximum number of items from this Producer.

Method Detail

request

void request(long n)

Request a certain maximum number of items from this Producer. This is a way of requesting backpressure. To disable backpressure, pass Long.MAX_VALUE to this method.

Requests are additive but if a sequence of requests totals more than Long.MAX_VALUE then Long.MAX_VALUE requests will be actioned and the extras may be ignored. Arriving at Long.MAX_VALUE by addition of requests cannot be assumed to disable backpressure. For example, the code below may result in Long.MAX_VALUE requests being actioned only.

 request(100);
 request(Long.MAX_VALUE-1);
 

Parameters:

n - the maximum number of items you want this Producer to produce, or Long.MAX_VALUE if you want the Producer to produce items at its own pace

Throws:

java.lang.IllegalArgumentException - if the request amount is negative