freePair() results in internal inconsistency in AbstractEnvironment

[Wouter1]

AbstractEnvironment extends EIDefaultImpl.

Therefore it inherits the freePair(agent,entity) function

freePair removes its references to the entity (from LinkedList? entities and ConcurrentHashMap<String, HashSet> agentsToEntities)

(BTW interesting but useless attempt here at making EIDefaultImpl thread safe by using ConcurrentHashMap??)

However AbstractEnvironment maintains its own copy of the existing entities: Map<String, Object> entities.

Because AbstractEnvironment never updates its copy when freePair is called, this results in an inconsistent state in AbstractEnvironment. For example, AbstractEnvironment#getEntity will still return the non-removed entity.

[Wouter1]

We discussed this, the proposal is to not keep shadow copies. If the hashmap is preferable (eg for performance reasons?), fix EIDefaultImpl and do not make shadow copies.

[Wouter1]

Added @OverRide to EIDefaultImpl functions that actually override, to clarify what is really implementation of EnvironmentInterfaceStandard.

It's not so easy to fix this in a clean way, I considered copying the code but EIDefaultImp is too large (1255 lines).
See also http://ii.tudelft.nl/trac/goal/ticket/3341