1. Case Study PrintService -dynamically networked products, services, and applications -network computer / consoles (powerful processor, several MB of memory) ©2001 Jerome Colombie

2. Infrastructure Requirements Java 2 platform, Standard Edition (J2SE) (May 8, 2000) Jini is written purely in Java JVM (powerful processor, several MB of memory) JRE 1.3 / JDK1.2.* (Solaris / Windows / Linux) network (TCP/IP)

3. Infrastructure Requirements 2

4. Software Requirements http-server (Class files, centralized, distributed) lookup-service reggie rmid (Activation, power saving, activatable hardware with standby) lease manager, lookup manager

5. Programming Requirements Discovery (Unicast / Multicast for maximum flexibility) Three Tiers (Thin-Client, dynamic GUI/driver, Print-Service) Thin-Client searches for specific Interface (Attributes: Address (vendor), Location, ServiceInfo, ServiceType, Status) GUI/driver (Transformation of Input-File, Printer-Selection) PrintService (Hardware abstraction, job-scheduling, billing data)

6. Prgramming Requirements 2 Client PrintManager (GUI / Driver) Printer PrintService

7. Interface Requirements Client / Server must share common Interface Beans (get and set methods for attributes) getAttribute(name, value) setAttribute(name, value) Attributes (Entry[], service specific attributes: driver, supported file-formats or languages, security-levels)

8. Attributes Find Service (Printer, Movieplayer, PCMCIA-Cards, wordprocessor) Load Interface (Entry[], TypeInfo, ServiceInfo, Manufacturer) Find Driver for Service (Printer driver, plug-ins, application from specific vendor)

9. Interface PrintService.java PrintService.java import java.rmi.*; public interface PrintService { public String print(String file) throws RemoteException; public boolean setAttributes(String room, String device, String format, String copies, boolean flag boolean psnup) throws RemoteException; }

10. Interface PrintManager.java PrintManager.java import java.rmi.*; public interface PrintManager { public boolean start(String clientinfo) throws RemoteException; }

11. What do we get? Dynamic loading of services without configuration or user-intervention the implementation of services is loaded dynamically, at runtime no administration (little) needed, ideal for dynamic environments A Jini Community is self-healing. (Printer failure)

12. Service registration Client PrintManager (Driver) PrintService PrintService register PrintManager register LUS

13. Discovery / Loading Client PrintManager (Driver) LUS 1. Discover Print- Manager 2. Load PrintManager (Local Execution)

14. Discovery / Printing Client PrintManager (Driver) LUS 1. Discover Print- Service 2. Print

15. Problems: Service Interfaces must be specified (a server is an implementation of a service) Interface is crucial. Both client and server know it. Jini Community (Developers) define set of common and ubiquitous interfaces http://www.jini.org/ http://www.jini.org/ Generic Interface (Use object reflection to learn the interface of a service, extendible)

16. Areas of application large systems (scalability) environments sensitive to security and fail-safety (robustness) distributed systems Ad-hoc networks

17. Key Features: open standards based environment Provides cross-platform compatibility, safe network delivery, and smartcard to supercomputer scalability dynamically networked products, services, and applications that scale from device to the enterprise rapid and cost effective development

18. Official Case Study from Sun: Jini[tm] Network Technology Drafted for Service in the U.S. Army Tactical Operation Centers control, execute, plan, and monitor battlefield maneuvers introduce new computing and communications elements into the network under battle conditions independent of computer re-starts, device drivers, system re- configurations, and extensive technical support increased TOC mobility and functionality