Marking Guide
Acronyms: Replica Manager (RM), Server Front End (FE), Tracking Service (TS)
Server Components (Total: 30 marks)
Implementation of 3 Replica Manager classes (5 marks)
o Alternatively, you can have 3 RM objects created from the same RM class running on 3
different RMI registries
• Implementation of the Server Front End class (5 marks)
The FE object and the 3 RM objects must be registered on different RMI registries running on
localhost but at different ports (5 marks)
o totally 4 RMI registries will be used, one registry for the FE to register and each RM
registers to a different registry
• The listTramService() method is implemented as a local method in the FE class (5 marks)
• The FE will not do any major Tram Tracking task. FE will only do the following tasks:
listTramService (check which RM is available), multicast remote method requests to available
RM, send returned results to Tram clients. (5 marks)
• All the tasks in FE (for example identify the registry, identify the remote servers, checking which
RM and server are working/not working) are separated into methods. (5 marks)
Client Component (Total: 10 marks)
• Many instances of the Tram class can be run simultaneously using multithreading (between each update request, each tram client sleeps for a time interval that randomly varies between 10 to 20 seconds) (5 marks)
• Tram clients only communicate with the Server Front End (5 marks)
Functionalities (Total: 40 marks)
• Each RM can be started and stopped when your application is running without interrupting your application (all Exceptions are caught correctly) (15 marks)
o While the system is running, at most 2 RMs can be killed and the system should continue
simulating the tram movement as usual.
Whenever a Tram client invokes a remote method on the FE, the FE will first invoke its
listTramService() method locally to find out which RM is running. The results of this listTramService() call must be printed out on the Console of the FE, for example: RM1 on | RM2 off | RM3 on. (15 marks)
After running the listTramService(), for each RM that is running, the FE will call the corresponding remote method on that RM, passing the input Message object and receiving a return Message object from that remote method call. So FE will multicast remote method calls to all available remote RM objects. Then the FE will forward only one returned Message object to the Tram client. (10 marks)
Other Requirements (Total: 20 marks)
Methods in the Remote interfaces only accept input arguments of type Message and return an object of type Message. Marshalling and unmarshalling operations must be applied as in Assignment 1 (10 marks)
All exceptions are caught and handled correctly. At least the following types of exception must be caught: RemoteException, NotBoundException, Exception. (5 marks)
All source codes are given detailed comments and formatted properly (5 marks)