Communication system, gui apparatus, and service apparatus

A communication system comprising:

• a GUI apparatus that performs screen construction based on an event notification;
• and
• a service apparatus that executes a service and generates an event, the GUI apparatus and the service apparatus being connected with each other through a network to perform mutual communication,
• wherein the GUI apparatus includes:
• a GUI apparatus-side event list memory that stores an event list and an ID corresponding to the event list, the event list being a list of the event;
• and
• a GUI apparatus-side event processor that refers to the GUI apparatus-side event list memory and, in a case where the event list required for performing the screen construction exists, obtains the ID corresponding to the event list to transmit the obtained ID to the service apparatus in place of the event list.

A service apparatus which is connected through a network with a GUI apparatus to communicate with each other, and which executes a service and generates an event, the GUI apparatus performing screen construction based on an event notification, the service apparatus comprising:

• a service apparatus-side event list memory that stores an event list and an ID corresponding to the event list, the event list being a list of the event;
• and
• an ID manager that manages a relation between the event list and the ID;
• and
• a service apparatus-side event processor that refers to the service apparatus-side event list memory when the event list is received from the GUI apparatus, and, in a case where the event list matching the received event list exists, obtains the ID corresponding to the existing event list and transmits a response message containing the obtained ID to the GUI apparatus, wherein, in a case where the event list matching the received event list does not exists, the service apparatus-side event processor obtains, from the ID manager, an ID unregistered with the service apparatus-side event list memory and resisters with the service apparatus-side event list memory the obtained ID and the received event list as one combination, and transmits a response message containing the obtained ID to the GUI apparatus, wherein, when an ID is received from the GUI apparatus, the service apparatus-side event processor refers to the service apparatus-side event list memory, and, when the event list corresponding to the received ID exists, transmits a response message containing the received ID to the GUI apparatus.