Java Doc for StandardTransactionalObject.java in  » Net » Terracotta » com » tc » test » transactions » Java Source Code / Java DocumentationJava Source Code and Java Documentation

This implementation allows reads to also be checked with a slight relaxation of the rules, called slop: if, when you read, you get a value that's invalid, but would have been valid were the read issued at any point up to slop milliseconds ago, it's treated as valid. This is used for our tests that involve the Terracotta database listener, as invalidations take a nonzero amount of time to travel.

Be warned: this class's implementation is quite tricky. Make changes with care, and re-run the test whenever you change it.

(The set of all values you could possibly read includes all values the object has had from the current time less the slop up to the start of the read, in addition to all values for which writes have at least been started (by calling startWrite(Object) for them) before the moment you called StandardTransactionalObject.endRead(Context,Object) .)

This class works in a bit of a funny way: if slop is exactly zero, we need to maintain order of method calls — many method calls can happen without System.currentTimeMillis changing at all. To do that, we simply use a Timing object, rather than a raw long, to store our times; there's one implementation (which we use if slop is nonzero) that uses just the raw time from System.currentTimeMillis , while there's another (which we use if slop is exactly zero) that uses both the raw time and an internally-generated sequence number, to distinguish calls that happen at the same 'time' (according to System.currentTimeMillis ).