Support for AND operations in EventCriteria

[CodeDrivenMitch]

While implemented a new way to construct EventCriteria, as follows:

EventCriteria criteria = EventCriteria
    .match()
    .eventTypes("StudentRegistered")
    .withTags(Tag.of("student", "studentA"))
    .or()
    .eventTypes("StudentAssignedToCourse", "CourseRegistered")
    .withTags(Tag.of("course", "courseB"))

However, in the current API the user is unable to create and AND condition, as this would create a few logical challenges:

1. While using the non-nested builder structure, it might be unclear which conditions you would AND.
2. While AND is logical for tags, it is not for event types. Event types are inherently OR, as an event generallty only has one type.

To demonstrate these points, let's see the following example:

EventCriteria criteria = EventCriteria
    .match()
    .eventTypes("StudentRegistered")
    .withTags(Tag.of("student", "studentA"))
    .or()
    .eventTypes("StudentAssignedToCourse", "CourseRegistered")
    .withTags(Tag.of("course", "courseB"))
    .andAllEvents()
    .areOfTypes("StudentAssignedToCourse")

As this is an AND condition, the type of the student now has to be of both StudentRegistered and StudentAssignedToCourse to match on the student tag, this is unlikely to ever happen.
As a second problem, is the API clear enough to indicate that this AND condition wraps all other conditions?

This issue serves as marker for later investigation.

[smcvb]

Lowering the priority if this ticket to a could and moving it to 5.0.0.
At the time being, we do not think there is a necessity for an AND operator on the EventCriteria.

Then again, the amount of users of the current API is minimal given the milestone status of AF5.
Hence, once AF5 is being used more and more, we should be better able to deduce whether an AND operator is what users expect/want.