Hands-On Reactive Programming in Spring 5

Subscription-time

The second important phase of the execution life cycle in the stream is the subscription-time. Subscription happens when we subscribe to a given Publisher. For example, the following code demonstrates how to subscribe to the aforementioned execution flow:

... filteredFlux.subscribe(...);

As we may remember from previous sections, in order to build an execution flow, we pass Publishers inside each other. So, we have a chain of Publishers. Once, we subscribe to the top wrapper, we start the subscription process of that chain. The following pseudocode shows how a Subscriber is propagated through the chain of Subscribers during the subscription time:

filterFlux.subscribe(Subscriber) {  mapFlux.subscribe(new FilterSubscriber(Subscriber)) ...