Thank you for information about JPA. I think that is what I need.
When I said 'real time' I meant that client should have possibility to ask current state of the hardware at any time and result should be received in not more then 1 sec.
Hardware can send message about state changing at any time and this message should be delivered to all clients in not more then 1 sec.
Status of the hardware can be changed very often. It could happen each second for some hardware objects. Total load is several tenth or hundred messages per second.
Client can send commands to hardware objects also. So, in any case I need to implement direct hardware request by demand.
Best regards,
Roman
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