jini architecture alessandro brawerman. contents jini definition advantages architecture how it...
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Jini Architecture
Alessandro Brawerman
Contents
Jini definitionAdvantagesArchitectureHow it worksWebsites to check
Distributed system - federating groups of users and the resources required by those users.Enables users to share services and resources over a network.Services can join or leave in a robust way, and clients can rely upon the availability of visible services until clear failure detections.
What is Jini?
Moving to client-client model.Network plug-and-work, dynamic configuration.Easy access to resources anywhere on the network.
Jini - Advantages
Erase the hard/software distinction.
Simplifies maintaining and altering a network.
Jini – Advantages (cont’d)
Based on JavaDynamically download and run codeBuilt-in securityRMIDepends on the Java environment rather programming.
Jini – Java technology-centered
ServiceProxyLookup Service Client
Jini – Architecture
Entity to be used by a person, program or another service.No hardware/software distinction.Dynamic nature – they can be added or withdrawal from a federation at any time.Examples: printers, disks, applications, databases, etc.
Services
Each lookup service provides a list of available services, communication procedure and attributes.
Lookup Service
Lookup Service A Lookup Service BClient A Client B Client C
Printer
Database
Calendar
Printer
Database
Printer Database Disk StorageDisk Storage
Discovery/Join Protocol
Lookup Services
Service sends a looking for lookup services
Lookup Services
Lookup Services respond
Join
Printer
Printer
Printer
It’s an object that teaches the client how to communicate with the service.The proxy is downloaded to the lookup services and then to clients.It can be the service itself.It can be an RMI stub.It can act as a smart adapter.
Proxy
Proxy – Currency Converter
CurrencyConv
Lookup ServiceClient
Proxy – Case 1
CurrencyConv
Client
CurrencyConv
Proxy – Currency Converter
Proxy – Case 2
Client
CurrencyConv
Service
CurrencyConv
RMI
500 dollars
365 UK Pounds
Proxy – Currency Converter
Proxy – Case 3
Client
CurrencyConv
Service
CurrencyConv
Dollar to UK pounds
0.75
RMI, CORBA, Socket, SOAP
Any entity that needs to use a service.Goes through a matching protocol:
Client
Lookup Services
Client sends a looking for lookup services
Lookup Services
Lookup Services respond
Lookup Services
Client searches fortype of services.
Printer
Printer
Lookup Services
Lookup Services return the proxies.
Printer
Printer
The Whole Process
Lookup Service
registration
Proxy
Printer Interface
Registering the service:
The Whole Process (Cont’d)
Lookup ServicePrinter Interface
Client
Looking up for printer interface
Proxy
Looking up for services :
The Whole Process (Cont’d)
Client
Using the service:
Services are registered for a bounded time. Special messages or Heartbeats.Proxies are leased for a bounded time.Clients can renew their proxies, if service permits.The leasing process takes care of fault detection.
Leasing
Leasing (cont’d)
Lookup ServicePrinter Interface
X
Lookup Service
Leasing (cont’d)
Lookup ServicePrinter Interface
Client
Printer interface
Leasing Renewal
Yes, Leasing Time
www.jini.orgwww.sun.com/software/jini/www.kedwards.com/jini/
References