Project from business Aspect
This project aims to provide http-server which is built by just using JDK
Main considerideration is creating performant and concurrent game score http services
There are 3 business service requirements as following
1-Generate session
2-Saving the games score based on generated sessions
3-Listing the high scores based game levels
Project from technical aspect
1- SimpleHttpServer class is to provide http server.
I have created custom ThreadPoolExecutor and ThreadFactory in order to have more control on resource management
Named threads
Used some dependancy injection and missed some since it can take time
Used magic numbers in class which wrong like 50000 queue capacity
I was planning to use PriorityBlockingQueue to prioritize some threads than others but I didn't
2- RootHandler:
Since HttpContext.createContext doesn't support regex and all required http enpoints start with "/<number>/<path>" pattern
I had to use single root handler and distributing the requests
I could use some handlers while distributing the requests in RootHandler also but using methods like createSession solved my issue
I have planned to carry the state with sessionkey like jwt. I tried to create sessionkey which has meaning for backend and no meaning for clients.
That is why I have tried some hashing, encoding util methods : createHashForUser(),encodeBase64()
Encoding is not good option while create sessionkey,
Hashing is not good option since I lose to access to userid after creating sessionkey
Correct way was encrpt with a constant salt time and metas like expire time,userinfo based sessionkey. So I could use access userid after decrypt it
3- UserScore: It is required to use ConcurrentSkipListSet which support sorting. I have tried also solved concurrency issue by
I have also solved concurrency issues using computeIfAbsent like atomic methods
4- Util: mostly static helper methods and constants which can be fed *.yml or *.json file in real prod app
5- HttpServerTest: I didn't use Junit or Mockito which are I am familiar with.
I have chosed thread based performance end-to-end test which cover more but miss atomic tests(bottom of the pyramid)
Main concern was concurrency for the test.
So saving the responses of services and verify them wouldn't be able to solve because which thread works earlier or later is unknown
I could verify the last hightScoreList after all threads are finished. But the hightScoreList strings should be concurrent. Tests for concurrency problems are hard.
I followed the logs of tests and services. For level10 high scores count should be 10