1. JINI Gijung Yun © Realtime Embedded Systems Laboratory Inha University
Java Intelligent Network Infra-structure 
Gijung Yun
© Realtime Embedded Systems Laboratory
Inha University
Version 1.2

2. Contents Introduction Jini Environment Jini Infrastructure
Vision and Charicteristic
Jini Environment
Jini Infrastructure
Jini Architecture
RMI Discovery, join and lookup
3. Leasing Events
5. Transaction 6. Services
Entry 8. Security

3. Introduction Jini Goals Network plug and work
Enable spontaneous networking
Promote service-based architecture
Simplicity
Resources can be implemented as either hardware devices, software programs, or a combination of the two.

5. 관련 기술 UPnP HAVi MS, Compaq, Intel, Philips…
Sony, Philips, Samsung, Sun…
가정내 AV기기를 접속하는 기술

6. Characteristic 100% Pure Java Collection of API’s and Protocols
Infrastructure
Built on RMI
Discovery, Join and Service Protocols
Lookup Service
Programming Model
Leasing Interface
Event and Notification Interfaces
Transaction Interfaces
Services
Fundamental entity of Jini
Reference Implementations Supplied

7. Jini Environment Java 2 compatible VM Network of reasonable speed
Multicast support preferable
Initial support for TCP/IP only
Class file server
HTTP most commonly used
Dynamic address allocation
DHCP
Devices should have some memory and CPU
Can use a ‘proxy’ as an alternative

8. Jini Infrastructure Jini
It is a set of software layers that together create a federation of computer devices and services
Directory Services
JavaSpaces
Jini
RMI
Boot, Discover, Join
Java VM
Windows
Unix
Other OS
or Devices

9. Jini Architecture
RMI
Discovery, Join & Lookup
Leasing
Events
Transactions
Services

10. Remote Method Invocation Object-Oriented RPC
RMI
Remote Method Invocation
Object-Oriented RPC
Similar to CORBA
Distinguished by ability to parse objects by value

11. Discovery, Join and Lookup
Find a Lookup Service
Multicast UDP for nearby Lookup services
Unicast TCP for known Lookup services
Join
Used by services to register with a Lookup Service
Registration Utility Classes
LookupDiscover for multicast discovery
LookupLocator for unicast discovery

12. Lookup Repository of available services
Stores each service as Java objects
Clients and services use to request a service type from a Lookup service
Search by type(Java Interface), not name
Closer to CORBA Trader service than CORBA Naming service

13. Discovery and Join Service Provider J 512 byte Discovery Multicast RMI
Join Upload
RMI
Reference
Jini Lookup
Service J
출처: Sun

14. Lookup Service Provider Service Consumer J J RMI Reference Lookup
Download
Discovery
Jini Lookup
Service J
출처: Sun

15. (sent via UDP multicast)
Request Message
(sent via UDP multicast)
Announcement Message
(sent via UDP multicast)
Discoverer
Lookup
Service
Discoverer
Lookup
Service
Request Message
(sent via TCP unicast)
Response Message
(sent via TCP unicast)
Response Message
(sent via TCP unicast)

16. Request packet format Vers <int> Port <int>
Where the discoverer wants replies
Sent to
Group
Len
<int>
Group 1
<string>
Group 2
<string> …
Desired groups
(length == 0  all)
Heard
Len
<int>
Heard 1
<svc id>
Heard 2
<svc id> …
Known Lookup
Services

17. Announcement packet format
Vers
<int>
Host
<string>
Port
<int>
My Id
<svc id>
Service information
(header)
Group
Len
<int>
Group 1
<string>
Group 2
<string> …
Groups that I am a
member of

18. Lookup Services
Maps interfaces indicating the functionality provided by a service to sets of objects that implement the service
Object
Store
Print
Service must be serialisable
and implement Entry
Copier
Printer
Fax
Canon HP
LBP-1260 J J J
출처: Sun
BJC-70
BJ-100

19. May be federated with other lookup services
Lookup service interface provides:
Registration, Access, Search, Removal

20. Network Issue IP-based Request Packet size limitation (512Byte)
Limiting the scope of multicast
TTL ( recommend 15 )

21. A form of Distributed ‘Garbage Collection’
Distributed Leasing
A form of Distributed ‘Garbage Collection’
Enables stability and resilience
Service is ‘loaned’ to a client for a certain period of time
Delegation of Lease Renewal
Allows clients/services to delegate lease renewal to a third party object

22. Attribute Modification
If a service is asked to change the set of attributes with which it registers itself,
it saves the changed set in a persistent store, then performs the requested change at each lookup service with which it is registered.

23. Registering and Unregistering with Lookup Services
register with lookup service
adds that lookup service to the persistent set of lookup services it should join,
and then registers itself with that lookup service.
unregister from lookup service
service is in the persistent set of lookup services to join, it should be removed from that set.
the service cancels the leases for all entries it maintains at that lookup service.

24. join a group
it adds the name of that group to the persistent set of groups to join,
and either starts or continues to perform multicast discovery using this augmented group.

25. leaving a group
It removes that group from the persistent set of groups to join.
It removes all lookup services that match only that group in the set of groups it is interested in from the set it has discovered using multicast discovery, and unregisters from those lookup services.
It either continues to perform multicast discovery with the reduced set of groups or, if the set has been reduced to empty, ceases multicast discovery.

26. Distributed Events Extends the standard Java event model
Adds features to provide resilience and determination in a distributed environment
Registration for event notifications is lease based
Unique event identifiers assigned to every event supplier
Event sequence numbers assigned to every event
Event types
Marshaled Object enables:
Store-and-forward
Notification filter
Notification MailBox

27. Transactions
Set of Interfaces that support the implementation of a two-phase commit protocol
Designed to be lightweight
Left to developer to implement as much (or as little) of the transactional semantics as they need
Lease based - transaction will fail if not completed within leased period
Supports distributed transactions
Sample Implementation supplied in Jini distribution

28. 출처: Sun

29. Services Services are defined by their interface Services must:
Discover and register with a lookup service(s)
Maintain the following across failures:
ServiceID(128bit) assigned by a lookup service
The service attributes that define its lookup entry
The group(s) the service participates in
Specific lookup services it must participate in
Maintain all leases with lookup services they have registered with
Utility Classes provided to manage these responsibilities

30. Using a Service Communication is between service and its proxy
Independent of wire protocol
Protocol can change without affecting client
RMI semantics core to functionality

31. Entry Typed set of objects, for matching
Provides extra information about services
A service may have any number of entries
Clients request services by class and/or by entries, using a simple matching system
Drawback:
relational operators such as < and != are not supported

32. There are some convenience subclasses of Entry:
Address: the address of the physical component of a service.
Location: the location of the physical component of a service. It can be used alone in a small, local organization.
Comment: a free-form comment about the service.
Name: name(s) of the service as seen by users.
ServiceInfo: generic information about a service. Includes the name of the manufacturer, the product, and the vendor.
ServiceType: human-oriented information about the "type" of a service. This is not related to its data or class types.
Status: the base class from which other status-related entry classes may be derived.

33. Security
The design of the security model for Jini technology is built on the twin notions of a principal and an access control list.
Jini services are accessed on behalf of some entity—the principal—which generally traces back to a particular user of the system.
Whether access to a service is allowed depends on the contents of an access control list that is associated with the object (entity).

34. The Sun Community Source License (SCSL)
Three Levels of Participation
Research and Education
Source code freely available
Can be used in any way other than deployment
Internal Deployment
Deployed code must pass a compatibility test
Commercialisation
Source code available with Jini trademark for a branding fee
Branding fee covers cost of trademark protection and compatibility testing
Low cost fee is based on either annual fee or royalty per device/service sold - whichever is the lower

35. Jini philosophy is useful
Summary
Jini limitations
TCP/IP, multicast, Java RMI, Java 2 VM
Jini philosophy is useful

36. Web Sites Reference http://www.jini.org/ http://java.sun.com/jini
Jini starter kit 1.2.1