Remove javadoc refs to non-public classes

[ajkannan]

Fixes #103

[mziccard]

@ajkannan If you don't mind I will go through this tomorrow morning (my morning:))

[ajkannan]

Yeah, that works fine, no rush!

[mziccard]

This is a general question that might stem from the fact that I haven't fully understood issue #103 but, why are we doing this?

Let me take the example of Value.BaseBuilder, all implementations in this PR are public static classes in public classes. Why do we need to override all setters given that Value.BaseBuilder is generic and setters return B?

If we decide that we need to override setters then are the self() method and the type parameter B still necessary?

[mziccard]

To add to my previous comment: if we decide not to have generic methods inside builders (i.e. to avoid relying on inherited methods with the signature B set(V value) but rather have Builder set(Boolean value)) then we should do that for all classes across gcloud-java.

This involves changing a number of classes (as ServiceOptions.Builder for instance) and adding a bunch of boilerplate code as @ajkannan had to do in this PR. I am not sure these changes are worth it and fear they lead to a less maintainable code. Opinions are welcome:)

[aozarov]

@mziccard You definitely have a point!

I think the problem is with classes/interfaces that uses generic types (in some cases to the extreme - such as ValueMarshaller and ValueBuilder) without documenting the types (so all their subclasses has an undocumented generic type in their javadoc).

In some cases we can fix that by documenting the generic types, though in other cases it may be simpler to override the method to the specific type.

I suggest to tackle this issue using a different approach and change the specific datastore interfaces/classes in this PR to package scope (as it is not likely that new types will be created outside of the library - we can revisit that in the future).

As for ServiceOptions and its Builder, lets add @param <..> type definition to their javadoc.

[ajkannan]

Changed this PR to document the types. It also makes a few base classes/builders protected and public to allow proper linking in the javadoc.