asyncGetAndLock returns the same value when a lock is refused and when a key is not found

This report is re: asyncGetAndLock method in the java client.

From the current implementation of asyncGetAndLock , it is impossible to tell the difference between

• a value that doesn't exist(& should be added) and
• a value that exists, but is locked by another client.

In both cases, you get this:
CASValue<T>(-1, null);

which customer opines is pretty non-useful in the cases where you want to decide whether to try again or move on to an add.

Suggestion from the customer is:

Add the CasGetStatus class which has additional information about the failure type (attached), and modify CouchbaseClient.java to create and return that class (diff attached).

Attached files:
1) CASGetStatus.java
2) couchbasediff.txt