Otto event failures

SomeKindOfEvent.java

Version 1:

package com.example.otto.sample;

public class SomeKindOfEvent {

        public final boolean wasSuccess;
        public final EventData eventData;

        SomeKindOfEvent(boolean success, EventData eventData) {
            this.wasSuccess = success;
            this.eventData = eventData;
        }
}

Version 2:

package com.example.otto.sample;

public class SomeKindOfEvent {

        public final EventData eventData;

        SomeKindOfEvent(EventData eventData) {
            this.eventData = eventData;
        }
}

public class SomeKindOfFailureEvent {
}

I would say the choice here lies in how and where you are going to interpret these events (which makes it highly subjective for each event) and the type of data. If the same piece of code is going to do very similar things for both the success case and the failure case then I would choose version 1. If two completely separate pieces of code are going to act based on success or failure then I would break them up. It's hard to say that one version is better than the other definitively. I think both have perfectly valid use-cases and you'd just need to make a decision on a case-by-case basis. Plus, since this communication is already decoupled it becomes really easy to switch between the two should your needs or requirements change!