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 RD 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 Jinis 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/sof
  tware/jini/news/success.xml

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Jini Logical Architecture
10
Jini Technology Flow Diagram
11
Jini Flow Example
1
2
4
3
12
Jini Architecture Diagrams
13
Implementation Components

• jini-core
• jini-ext
• Reggie - LUS Implementation
• jsk-policy - Security Implementation
• Many others

Discovery, Lookup, Lease, Implementations
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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

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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

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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

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Distributed Events
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Distributed Events
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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

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Code Snippet Examples

• Unicast Lookup
• import net.jini.core.discovery.LookupLocator
• public class Locator
• public Locator
• LookupLocator lookup
• try
• lookup new LookupLocator(jini//localhos
  t)
• catch(java.net.MalformedURLException e)

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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()

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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)

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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

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Code Snippet Examples

• Consume a Service contd.
• // Set a security manager otherwise we cant load
  the codebase
• System.setSecurityManager(new RMISecurityManager()
  )
• Class toasterClasses new Class1
• toasterClasses0 Toaster.class
• // Do the usual Lookup and Registrar Creation
• // Prepare a seach template of serviceID, classes
  and entries
• ServiceTemplate template new ServiceTemplate(nul
  l, toaterClasses, null)
• // Let us find the Toaster
• Toaster toaster null
• try
• toater (Toaster) registrar.lookup(template)
• catch(javam.rmi.RemoteException e)

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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

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JINI Framework-based Services

• Rio
• Dynamically instantiate service component
• Monitor service component
• Manage service component
• Pluggable load distribution and resource
  utilization analysis

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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/reconfigurabl
  e
• 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

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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-datashe
  et0601.pdf
• http//www.javacoffeebreak.com/books/samples/profe
  ssionaljini/3552_Chap7_idx.pdf

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References

• http//developer.apple.com/opensource/internet/bon
  jour.html
• http//www.apple.com/support/downloads/bonjourforw
  indows.html
• http//www.zeroconf.org/
• http//msdn2.microsoft.com/en-us/library/aa382261.
  aspx
• http//www.sun.com/software/jini/index.xml
• A Programmers 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/