HOW to start:
mvn clean compile assembly:single && java -jar target/mini-game-backend-1.0-SNAPSHOT-jar-with-dependencies.jar
How to stop:
Ctrl+C
The program implements standard MVC pattern to serve concurrently http requests and used in-memory storage for
data persistence.
- MVC. Controllers receive requests, routed by Java's HttpServer, to controller methods. Each controller validates
the request param, calls certain model to add/fetch data optionally uses view to create formatted string and lastly
writes response to HttpServer, which takes over and displays it in the browser. In case of errors, such as validation
error, 400/Bad request with empty body is returned.
- Multithreading. For each request HttpServer creates a separate thread with newCachedThreadPool() ExecutorService.
The controllers are static and therefore shared between threads reading and writing to the controller's state. The
state is delegated to models and each model in terms delegates concurrency handling to ConcurrentHashMap, which is
high performance multithreaded data structure, with minimum blocking and atomic methods. There is only one place in the
code where synchronisation is used -- Authenticator's login method -- and this can probably be improved with some
clever sequence of atomic method calls, like in ScoreList's add method.
- Testing. There are both integration tests -- in AppTest -- as well as unit tests in AuthenticatorTest. More tests
needs to be added.
- Data structures. ConcurrentHashMap is used all over mainly for simplicity. In order to support the generation of
top score lists ConcurrentSkipListMap can be used instead, so one keeps the scores sorted and does not re-sort them
in each method call.
- Misc. There are various TODOs in the code, describing extensions/improvements. There are no comments since the code
is hopefully self-explanatory.