To obtain sessionId, sessions map is sought for value

[dimaa6]

Java-OCA-OCPP/ocpp-common/src/main/java/eu/chargetime/ocpp/Server.java

Line 174 in 5c608f8

if (!sessions.containsValue(session)) {

This happens each time request is received. Server may be handling hundreds of thousands of connections, with hundreds of requests coming in every second. Synthetic test with map having 100,000 UUID keys pointing to String values and 1000 containsValue calls took 4 seconds. Test with the same map and 1000 containsKey calls took only 0.1ms. This shows that containsValue method does not utilize Map's ability to quickly find an object, instead, it iterates through all the values in regular scanning loop. If we really need to check if session is still present, we need to have Set of sessions in addition to the Map, and handle them together in atomic (synchronized) way - when adding a session, add it to both Map and Set, same when removing. Then Set will be used to quickly check if the session is still active.

[TVolden]

Hi @dimaa6,

Thank you for reaching out. I'm happy to hear that business is good.

You are right of cause, it's a waste of resources to use containsValue. Especially if the UUID is already stored in the session via the getSessionId method.

Can I get you to create a PR for the change?

Sincerely
Thomas Volden

[dimaa6]

Sure, will do tomorrow.