Jini™

1. Jini™ Rashad Oreifej and Christopher Stricklan

2. Introduction • Pronounced GEE-nee • Stands for (Java INference engine and networked Interactor)? • Loosely derived from the Arabic for magician? • Some said it stands for Jini Is Not Initials Nobody really knows.. • An open Java™ technology-based architecture enables organizations to build adaptive network-centric systems to allow services to be added, upgraded or removed dynamically, whilst the network remains up and running • “Plug and Work” network

3. History • Developed by Sun MicroSystems • The idea started by Sun cofounder Bill Joy at Sun Aspen Smallworks R&D lab in 1994 • Under the leadership of Bill Joy and Jim Waldo: • Ann Wollrath • Ken Arnold • Bob Scheifler

4. History • Based on the unique distributed computing characteristics of Java technology and the RMI • Introduced in January, 1999 by providing the first Jini Technology Starter Kit • Sun currently has agreement with a wide range of technology companies to develop Jini technology services, both hardware and software. • Includes Axis, Canon, Datek, Epson, FedEx, Mitsubishi, Norwest Mortgage, Novell, ODI, Quantum, Seagate, Toshiba, Computer Associates, Oki, Salomon Brothers

5. Benefits • Provides the infrastructure for creating dynamically networked components (SW/HW), applications, and services • No configuration overhead and device drivers • Extends the Java programming model to the network (moves data and executables via a Java object over a network) • Consistent access to local and remote devices

6. Benefits • Network self-healing and self-configuration (Leasing) • Networks adapt to changes in the computing environment • Allows fast, easy incorporation of legacy, current, and future network components • Jini is available free of charge • Enables computer networks to resemble phone networks in graceful connection/disconnection and scalability • Enables all types of digital devices to work together in a community put together without extensive planning, installation, or human intervention

7. Limitations • Sun Community Source License (SCSL) licensing model • Lookup criteria that include ranges of values to match or sets of values to match, cannot be expressed with a single ServiceTemplate • Low-resource clients

8. Success Stories • Orange API 2 incorporates Jini technology as one of the first implementations of Jini in telephony network Web services environment • RFID networks enable and support new business processes. Such a distributed network benefits from Jini’s robust self-managing and self-healing capabilities • U.S. Army developed a battlefield-ready solution based on Jini connection technology that allows computers and other devices to interoperate immediately after being connected. • Other many success stories: http://www.sun.com/software/jini/news/success.xml

9. Jini Logical Architecture

10. Jini Technology Flow Diagram

11. Jini Flow Example 1 2 3 4

12. Jini Architecture Diagrams

13. Implementation Components • jini-core • jini-ext • Reggie - LUS Implementation • jsk-policy - Security Implementation • Many others… } Discovery, Lookup, Lease, … Implementations

14. Lookup Discovery Service (LDS) • Unicast Discovery Protocol (Locator) • For LUS outside the LAN • Address is already known • Multicast Discovery Protocol (Group) • LUS within the LAN • Address in not known.

15. Unicast Discovery Protocol • Package: net.jini.core.discovery • Client/service sends a unicast request (packet) using the TCP protocol Unicast TCP • LUS unicast announcement reply Unicast TCP • Client/Service downloads the LUS proxy • Join (Send proxy class, Service ID, Attributes) Unicast TCP • Lookup (Obtain RMI interface to service) Unicast TCP

16. Multicast Discovery Protocol • Package: net.jini.discovery • Client/service sends a multicast request (packet) that contains the groups of interest Multicast UDP • LUS multicast announcement reply Multicast UDP • Client/Service downloads the LUS proxy • Join (Send proxy class, Service ID, Attributes) Unicast TCP • Lookup (Obtain RMI interface to service) Unicast TCP

17. Jini Lookup • Lookup types “Templates” rather than names • Lookup by a class type “Super and Sub classes can be included” • Lookup by multiple types (AND/OR operators) • Lookup by specific attributes • Lookup by Service ID

18. Lease Service • Leasing concept is introduced to recover from the loss of services • Prevents resource starving at the LUS due to allocations for dead services • Each service is registered in the LUS for a certain time “Lease” • Upon expiry either renew, or be removed • Lease requester can cancel the lease any time

19. Distributed Events

20. Distributed Events

21. Distributed Events • Discover an instance of a LUS • Register with the LUS in order to be notified when a specific service (template) joins and leaves the Jini network • Catch the join and leave remote notifications from the LUS

22. Code Snippet Examples • Unicast Lookup import net.jini.core.discovery.LookupLocator; public class Locator{ public Locator{ LookupLocator lookup; try{ lookup = new LookupLocator(“jini://localhost”); }catch(java.net.MalformedURLException e){ } } }

23. Code Snippet Examples • Get Registrar … // Other imported packages import net.jini.core.lookup.ServiceRegistrar; public class UnicastRegister{ public UnicastRegister{ LookupLocator lookup = null; ServiceRegistrar registrar = null; … // Lookup Service code here try{ registrar = lookup.getRegistrar(); }catch(){} } }

24. Code Snippet Examples • Register a Service … // Other imported packages import net.jini.core.lookup.ServiceItem; import net.jini.core.lookup.ServiceRegistration; Public class SimpleService implements Serializable{ public SimpleService(){ … //Lookup Service Code … // Registrar Code ServiceItem item = new ServiceItem(null, this, null); ServiceRegistration reg = null; try{ reg = registrar.register(item, 10000); // Registers for 10 seconds }catch(jama.rmi.RemoteException e){} } }

25. Code Snippet Examples • Consume a Service // First we need an Interface public interface Toaster extends java.io.Serializable{ public void setDarkness(int dark); public void startToasting(); } // The actual also needs to be implemented public class MySuperToaster implements Toaster{ public void setDarkness(int dark){ … // do something here } public void startToasting(){ … // Lets make the toast yummy } }

26. Code Snippet Examples • Consume a Service contd. // Set a security manager otherwise we can’t load the codebase System.setSecurityManager(new RMISecurityManager()); Class[] toasterClasses = new Class[1]; toasterClasses[0] = Toaster.class; … // Do the usual Lookup and Registrar Creation // Prepare a seach template of serviceID, classes and entries ServiceTemplate template = new ServiceTemplate(null, toaterClasses, null); // Let us find the Toaster Toaster toaster = null; try{ toater = (Toaster) registrar.lookup(template); }catch(javam.rmi.RemoteException e){}

27. JINI Framework-based Services • JavaSpaces • based on Tuple-Spaces • Provides a reliable distributed storage system for objects • Supports atomic access to objects • Built-in transactional mechanism • Object Leases • Events

28. JINI Framework-based Services • Rio • Dynamically instantiate service component • Monitor service component • Manage service component • Pluggable load distribution and resource utilization analysis

29. JINI Framework-based Services • Seven • Eases the development and deployment of Jini services • Administration interfaces for life-cycle and join management • Role based access control for remote method invocations • Security is dynamically configurable/reconfigurable • Resource efficiency by reducing the number of threads that are used by the Jini classes

30. JINI Framework-based Services • Harvester • Claims to simplify Jini application development • Build services using a servlet-like API • Help manages codebase • Provides an HTTP server for codebase downloads • Supports writing Jini services with Python through a wrapper class called Jython

31. JINI Framework-based Services • Newton • Moves code around the network installing on demand • Removes the code when no longer in use • Dynamically wires up runtime service dependencies • Rewires dependencies as services come and go.

32. Applications • Distributed File System • Directory Service • Mobile Networks • Auto Printer Configuration • RFID • Agent Implementations • Grid Computing

33. Apache River Moved Jini from SCSL to Apache License v2.0 (ALv2) Occurred March 2005 • Why Apache? • It was a community decision • Extensive, open, and collaborative discussions • ALv2 was determined to best meet the licensing requirements most important to Sun and the Jini Community.

34. Apache River • Motivation • Allow Broader Adoption • Technical Advancement • Meet needs of expanding Jini community

35. Apache River • Benefits • Develops a richer ecosystem for Jini technology users to operate within • Freely license, use and distribute Jini technology • Simplify prospective users license review process • Simplify the introduction of Jini technology into many companies

36. Other SOAs • Zero Configuration Networking (Zeroconf) • Created by The Engineering Task Force • IPv4 Link-Local Addressing Based • Allocate addresses without a DHCP server • Translate between names and IP addresses without a DNS server • Find services, like printers, without a directory server

37. Other SOAs • Bonjour • Created by Apple • Based off of ZeroConf • Open Source • Creates dynamic network of computers • JAVA library, MAC OS, and Windows Compatible • IP Based through UDP Port 5353 • Allows discovery of services through web browser

38. Other SOAs • UPnP • Created by Microsoft • Supports zero-cofiguration • Media and Device Independent • Platform Independence • Built on internet-based technologies (IP, TCP, UDP, HTTP, XML, etc.) • Extendable

39. Conclusions • Jini • Developed by SUN • Dynamic Networking Architecture • Zero Configuration • Remote Method Invocation

40. Conclusions • Pros • Create a Dynamic Environment • Open Source • Cross-Platform Support • Mobility of Code • Protocol Agnostic • Network Self-Healing • Network Self-Configuration

41. Conclusions • Cons • Lookup Criteria • Limited Debugging Support • Type conflicts when mixing objects from different code bases • Changes in codebase may fail to reach client

42. References • http://www.jini.org • Jini and JavaSpaces Application Development, Robert Flenner. SAMS Publishing, 2002 • The Power and Limitations of the ServiceRegistrar Interface, Bill Venners. Published in JavaWorld, 2000 • http://www.sun.com/software/jini/news/success.xml • www.assuredtech.com/papers/jini/embedded.pdf • www.sun.com/software/jini/whitepapers/jini-datasheet0601.pdf • http://www.javacoffeebreak.com/books/samples/professionaljini/3552_Chap7_idx.pdf

43. References • http://developer.apple.com/opensource/internet/bonjour.html • http://www.apple.com/support/downloads/bonjourforwindows.html • http://www.zeroconf.org/ • http://msdn2.microsoft.com/en-us/library/aa382261.aspx • http://www.sun.com/software/jini/index.xml • A Programmer’s Guide to Jini Technology, Jan Newmarch, Apress, 2000 • Class Loading Issues in Java™ RMI and Jini™ Network Technology, Michael Warres, Sun Microsystems, 2006

44. References • https://rio.dev.java.net/overview.html • http://www.cheiron.org/seven/ • https://harvester.dev.java.net/ • http://newton.codecauldron.org/ • https://rio.dev.java.net/