GeoJava
CoLoS project Milano

GeoJava
architecture

The application is a client-server system. The client module is launched to open a stand-alone session, whereas the server has to run in order to listen to calls from clients asking to co-operate. The server receives from clients both graphics messages on one socket that will then be distributed to all drawing areas of the active clients, mantaining consistency among them, and text messages on the second socket that will be displaied in the communication window, so that the work in progress can be commented. The server can cope with concurrent requests from clients, generating a so called thread for each client.

The protocol for text messages is the following:

[TALK] [string], to send a message to all partners

[PRIVATE] [string] [id], to send a message to a specified partner.

Whereas, the protocol for the graphic exchange is the following:

[ACTION] [object type] [object] [[object]], where ACTION gives an indication of the action to perform on the geometric object (e.g. the message INTERSECT_LC Object_Line line1 Object_Circle circle2 sent to each client will generate the two intersections points between the line named line1 and the circle named circle2)



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