[infinispan-dev] Distributed Counter Discussion

Hi everybody, Discussion about distributed counters. == Public API == interface Counter String getName() //counter name long get() //current value. may return stale value due to concurrent operations to other nodes. void increment() //async or sync increment. default add(1) void decrement() //async or sync decrement. default add(-1) void add(long) //async or sync add. void reset() //resets to initial value Note: Tried to make the interface as simple as possible with support for sync and async operations. To avoid any confusion, I consider an async operation as happening somewhat in the future, i.e. eventually increments/decrements. The sync operation happens somewhat during the method execution. interface AtomiCounter extends Counter long addAndGet() //adds a returns the new value. sync operation long incrementAndGet() //increments and returns the new value. sync operation. default addAndGet(1) long decrementAndGet() //decrements and returns the new value. sync operation. default addAndGet(-1) interface AdvancedCounter extends Counter long getMin/MaxThreshold() //returns the min and max threshold value void add/removeListener() //adds a listener that is invoked when the value change. Can be extended to notify when it is "reseted" and when the threshold is reached. Note: should this interface be splitted? == Details == This is what I have in mind. Two counter managers: one based on JGroups counter and another one based on Infinispan cache. The first one creates AtomicCounters and it first perfectly. All counters are created with an initial value (zero by default) The second generates counters with all the options available. It can mix sync/async operation and all counters will be in the same cache. The cache will be configure by us and it would be an internal cache. This will use all the features available in the cache. Configuration-wise, I'm thinking about 2 parameters: number of backups and timeout (for sync operations). So, comment bellow and let me know alternatives, improvement or if I missed something. ps. I also consider implement a counter based on JGroups-raft but I believe it is an overkill. ps2. sorry for the long email :( I tried to be shorter as possible. Cheers, Pedro