Fwd: design a finite state machine for a FIX engine

We need a cache of all the pending orders we created. All from-exchange FIX messages must match one of the pending orders. Once matched, we examine its current state.

 

If the message is belated, then we must reject it (informing all parties involved).

 

If the message is delivered out of sequence and too early, then we must keep it on hand. (a 2^nd cache)

 

If the message is for immediate consumption, then consume.

 

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the FSM in FIX is about state transition and should be pertinent to all state machines. Basically, it goes from pending new to new to fill or cancelled. From cancelled, it cannot go back to new or fill etc.

Anthony