Fix TCAP dialog put-get collision in TCAPProviderImpl

[Oleg-Afanasiev]

Hello,

This PR is solution for issue#107. TCAP->TCAPProviderImpl->onMessage - was added synchronized blocks.

Brgds,
Oleg Afanasiev

[deruelle]

Thanks @Oleg-Afanasiev for signing the CLA and for the PR ! @vetss will review the PR

[deruelle]

Just a quick comment, instead of using synchronized on dialogs, can't we use a ConcurrentHashMap instead this would perform better than using synchronized keyword especially with places like https://github.com/Oleg-Afanasiev/jss7/blob/2e4a025ebab65377970be41347467f04055e15bd/tcap/tcap-impl/src/main/java/org/mobicents/protocols/ss7/tcap/TCAPProviderImpl.java#L584 where we only do get...

[vetss]

Hello @Oleg-Afanasiev,

can you please comment your update ? I mean why do you think that we need to inlude "di = this.dialogs.get(dialogId);" into synch() blocks. Do you have some concrete experiense that the current code brings you any problems that you have detected ?

I have also created an issue for discussing of synching issues
#110
Feel free to add there any comments.

[Oleg-Afanasiev]

Hello. Thanks for discussing. Yes, we have concrete problems with "this.dialogs.get(dialogId)". We made high load tests under competitive environment. But we couldn't tested without fixing TCAP library (placing this fragments of code into synch() blocks), because put-get collisions were happen as described in #107.

[vetss]

Hello @Oleg-Afanasiev,
ok, thanks for a valuable info.

As for your concete commit I need just to note that it is better to remove code like:
dialogId = Utils.decodeTransactionId(tcm.getDestinationTransactionId());
from "synchronized (this.dialogs)" block and leave their only code like "this.dialogs.get(dialogId)".

Let's continue discussing in #110.
I am thinking that may be it will be more effective to use instead of FastMap<Long, DialogImpl> another collection like ConcurrentHashMap that can be used without synchronized blocks.