Patent ID: 8482770

Claim:
A data processing apparatus that requests an external apparatus to execute a part of sequential processing, receives a control request from the external apparatus, and executes the sequential processing in response to the control request that reflects an execution result of the part of the sequential processing performed by the external apparatus, the data processing apparatus comprising: a generation unit configured to generate identification information that can be used to determine whether a processing execution request sent to the external apparatus is output via an operation unit of the data processing apparatus; a storage unit configured to store the identification information generated by the generation unit in a storage medium; a transmission unit configured to transmit the identification information generated by the generation unit to the external apparatus; a reception unit configured to receive the control request from the external apparatus; a determination unit configured to determine whether the identification information stored on the storage unit coincides with identification information added to the control request received by the reception unit; and an execution unit configured to execute processing to be performed based on the control request if the determination unit determines that the identification information stored on the storage unit coincides with the identification information added to the control request received by the reception unit, wherein the execution unit is configured to execute the processing to be performed based on the control request after completing execution of processing to be performed based on the identification information stored on the storage unit, if the determination unit determines that the identification information stored on the storage unit does not coincide with the identification information added to the control request received by the reception unit.