Patent ID: 6876994

Claim:
A data acquisition apparatus for acquiring data from a transmitted data stream in accordance with requests received from a plurality of data processing apparatuses, the data acquisition apparatus comprising: a request receiving means for receiving a plurality of requests to acquire data, from the plurality of data processing apparatuses; a condition generating means for generating a plurality of conditions corresponding to the received requests; a scheduling means for generating a queue of the plurality of conditions and setting, according to the generated queue, one or more conditions in a data extracting means and/or eliminating the one or more conditions from the data extracting means; the data extracting means starts to acquire from the data stream one or more pieces of data that satisfy the one or more conditions when these conditions have been set by the scheduling means, and ending the acquiring of the one or more pieces of data that satisfy the one or more conditions when these conditions have been eliminated by the scheduling means; and an outputting means for outputting the one or more pieces of data extracted by the data extracting means to data processing apparatuses that have sent requests to acquire the one or more pieces of data, among the plurality of data processing apparatuses; wherein the request receiving means further receives together with each request a piece of monitoring state information that specifies a data acquisition state; and the scheduling means (a) continuously sets a condition corresponding to a request in the data extracting means when the scheduling means receives the request with a piece of monitoring state information that specifies a perpetual monitoring acquisition, (b) repeatedly sets and eliminates a condition corresponding to a request in/from the data extracting means at predetermined intervals when the scheduling means receives the request with a piece of monitoring state information that specifies an intermittent monitoring acquisition, and (c) sets a condition corresponding to a request in the data extracting means and eliminates the condition from the data extracting means once one piece of data that satisfies the condition has been acquired by the data extracting means when the scheduling means receives a request with a piece of monitoring state information that specifies a non-monitoring acquisition.