MobileSpaces JavaSpaces for mobile devices

1

• MobileSpaces JavaSpaces for mobile devices
• Tomasz Rybicki, Jaroslaw Domaszewicz
• Warsaw University of Technology

2
Agenda

• Brief description of the system
• Architecture
• Differences with JavaSpaces
• Code example
• Conclusion

3
MobileSpaces

• Tuple space for mobile devices
• Targeted at J2ME (MIDP) devices
• especially mobile phones
• Provides mobile applications with local tuple
  space abstraction
• JavaSpaces-like API
• Employs
• Java (J2ME, J2SE)
• Jini,
• Jini Surrogate Architecture,
• Jini JavaSpaces Service

4
Architecture
5
Architecture
6
MobileSpaces Client

• Is a part of mobile application
• Written for CLDC 1.1 MIDP 2.0
• Hides the connection details from the mobile
  application
• Provides the mobile programmer with an
  abstraction of local tuple space

7
MobileSpaces Surrogate

• Runs in the Surrogate Hosts environment
• Full J2SE compliant software
• Acts on behalf of MS Client

8
MobileSpaces
Device
Surrogate Host
App.
space
MS Surrogate
MS Client
ServiceConnector
surrogate thread
JS
service
sign.
communicator
communicator
XML
transporter
transport server
9
MobileSpaces and JavaSpaces major API
differences

• Different tuple definition
• Simplified event registration mechanism
• No snapshot
• No transactions

10
MobileSpaces code example accessing tuple space

• SpaceConnector sc new SpaceConnector()
• Space space sc.getSpace()

11
MobileSpaces code example writing a tuple

• OEntry tuple new OEntry()
• tuple.setField(0,John) // Recipient
• tuple.setField(1,Hello)// Message
• tuple.setField(2,Mary) // Sender
• space.write(tuple,timeout2)

12
MobileSpaces code example notifications

• OEntry template new OEntry()
• template.setField(0,John)
• space.notify(template,timeout1,EventHandler)

13
MobileSpaces code example notifications

• public interface EventHandler
• public void handleEvent(OEvent oevent) //
  notify the user

14
Conclusion

• Gives MIDP applications access to JavaSpaces
• Easy to use
• API similar to JavaSpaces API porting easy
• The use of Surrogate Architecture make the system
  flexible
• Some work has to be done

15
Thats all.

• Any questions?