Question 1 - General concepts (20 marks)

A common scenario in the ubiquitous world is that things should "happen" in the morning when you wake up. What should happen? What sensors, motors, etc would be needed for these to happen?

Question 2 - Service specification in Java (20 marks)

A washing machine can

• Set the water level, the water temperature and the wash type (heavy, ordinary, wool wash)
• Signal when it is time to put in softener
• Inform when it has finished
• Answer how long it will take before the wash finishes

Consider the washing machine as a service

• What events are generated by the washing machine?
• What are the getter and setter methods?
• Write a Java interface for the washing machine as a remote service

Question 3 - Multiple service interaction (20 marks)

A distributed telephone in future might separate the components of phone network connection, answering machine and handset, all connected by wireless network (e.g. Bluetooth). For example, the handset might be any PDA, the answering machine might be any storage device such as a networked disk drive, and the phone network connection might be the phone base station.

Suppose all three device types (PDA, storage, phone base) are available as services (or clients) on a network. What possible messages and data streams might be sent between them? Draw diagrams to show the devices, the messages and the data streams.

Question 4 - MIDP (20 marks)

Following on from Question 3, write MIDP code to allow the PDA to be used as a handset. When the handset midlet is started, it should allow the user to query a phone book stored in a RecordStore or allow direct entry of a phone number. When a number is dialled, the phone should start a PhoneConnection object running in a separate thread (you do not need to implement this object). The midlet should then display a "stop" button which will call the method PhoneConnection.stop() when selected.

Question 5 - Jini (20 marks)

Some services may only have one user at a time. For example, a car can only have one driver at a time. This could be implemented by a service advertising itself to lookup services when it is free, and cancelling the advert when it is in use. It could have methods such as useMe() and releaseMe().

• Explain how Jini could do this (Hint: registering a service with a lease renewal time of zero will remove it from the lookup service). Illustrate with pseudo-code using Jini objects such as ServiceRegistrar.
• What problems may arise from this method of implementation?