[Sandesha2] The Policy model

[Chamikara Jayalath]

Hi All,

I'm working on implementing the policy model for sandesha2. Sanka has already created a RMPolicyBean  and a PolicyUtil class which can be used to extract a RMPolicyBean out of a large Policy OM Element. The problem is how to pass this extracted information around the Sandesha2 framework.

This is what I have in mind.

Each messageContext should have an associated RMPolicyBean which contains its policy information. In the client side this information will be set by the user (probably wrapped by the stub). In the server side, a fixed set of policy values (given in the module.xml) will be loaded to the RMPolicyBean. This infoamtion will be later set to each messageContext.


Here are how these policies can be used.

Rretransmission interval, exponention backoff
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The RetransmitterBean will adjust the nextTimeToSend after each retransmission. To calculate the nextTimeToSend, the sender will use these two policy values (with the sentCount property which gives the no. of times the message has been retransmitted) which can be obtained from the associated RMPolicyBean of the current message Context.


Acknowledgement interval
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When adding a ack message the timeToSend will alsays be set to currentTime+Acknowledgement Interval so that the ack message will not be send before the interval get expired. When the sender detect an applicationMessage  it will look for an ack of the same sequence. If it find one, the ack will be piggybacked. otherwise the ack will be sent as a standalone message.


Inactivity timeout
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Each sequence has an associated lastRespondedTime property which gives the last time the other end responsed. Sender thread in it's each loop will look at the the lastRespondedTime of each sequence, if it find tha currentTime>lastRespondedTime+inactivityTimeout it will end that sequence.


Comments ???


Thanx,
Chamikara