AggregateState PDU updated

[fo-ifad]

added classes to represent Silent Aggregate -and Entity Systems , used these in Aggregate state PDU and changed the "pad2" attribute to be dependent on how many Aggregate and Entity ID are in PDU lists, to fit IEEE Std 1278.1a-1998 section 5.3.9.1

[leif81]

Thank-you @fo-ifad

If possible, could you create a unit test for the AggregateSystem PDU class and at it to this PR?

For an example, see the unit test named EntityStatePduTest. https://github.com/open-dis/open-dis-java/blob/master/src/test/java/edu/nps/moves/dis/EntityStatePduTest.java This was done by capturing a PDU with WireShark (not sent by Open DIS), and then using the unmarshal and marshal methods of the class

[leif81]

@fo-ifad great job on the unit test.

I overlooked something earlier because I am not very familar with the Aggregate State PDU. If I'm understanding it this is a new PDU added in DIS 7? If so, can you move the classes into the edu.nps.moves.dis7 package here. The dis package is DIS 6.

[fo-ifad]

Thanks

The Aggregate State PDU was introduced in IEEE 1278.1a-1998, so I think it is placed correctly in the dis package, and I think the Aggregate State PDU is a little different in DIS7, I haven't really made a deep dive into that yet.

Version 5 - IEEE 1278.1-1995
Version 6 - IEEE 1278.1a-1998 (amendment to IEEE 1278.1-1995)
Version 7 - IEEE 1278.1-2012 (See External Link - DIS Product Development Group.) Version 7 is also called DIS 7.