bundle programming

aQuteBundle Programming

By Peter KriensCEO aQute

OSGi Technology Officer andOSGi Fellow

©1999-2004 aQute, All Rights Reserved slide #2

Contents


Content R1, R2, R3

Framework

OSGi Specifications Content

Execution Environment

Devic

e M

anag

er

Log

Serv

ice

Http

Ser

vice

R1

User

Adm

in

Serv

ice T

rack

er

Conf

igur

atio

n Ad

min

Pref

eren

ces

Serv

ice

Pack

age

Adm

in

Perm

issio

n Ad

min

R2

Conn

ecto

r Ser

vice

Posit

ion

XML

Pars

er S

ervic

e

UPnP

Ser

vice

Jini S

ervic

e

Wire

Adm

in

Mea

sure

men

t

Star

t Lev

el

URL

Hand

ler

R3 Preliminary


org.osgi.service.log v1.1Log Service

• Simple and small Log service for operator

• 4 Levels– INFO, DEBUG, WARNING, ERROR

• Automatically logs framework events in a defined way

• Other bundles can access log history– Management bundle– Length implementation dependent


org.osgi.service.log v1.1Log Service

a log usera log user a log readera log reader

LogServiceLogService LogEntryLogEntry LogListenerLogListener LogReaderService

LogReaderService

a log service impl.

a log service impl.

A log entryimpl.

A log entryimpl.

A log readerimpl.

A log readerimpl.

Log Service Impl. bundle

Log a message

Store a message for retrieval and broadcast

Message log

Send new log entry

Retrieve log

A loguser bundle

A logreaderusing bundle


org.osgi.service.http v1.1Http Service

• Provides web access to bundles

• A powerful servlet runner– Supports Servlets Version 2.1

• Very simple to export static pages and files (like images)

• Automatically unregisters servlets when bundle is stopped


org.osgi.service.http v1.1Http Service

Impl. Of Httpcontext

Impl. Of Httpcontext

Impl. Of servlet

Impl. Of servlet

HttpContextHttpContext NameSpaceException

NameSpaceException HttpServiceHttpService

javax.servlet.Servlet

javax.servlet.Servlet

Default impl.HttpContext

Default impl.HttpContext

Resourceregistration

Resourceregistration

Servletregistration

Servletregistration

Bundles main code

Bundles main code

javax.servlet.Request/Response

javax.servlet.Request/Response

NameSpacealias

NameSpacealias

An Http Serviceimpl.

An Http Serviceimpl.


org.osgi.service.device v1.1Device Access

• Dynamic device driver download model

• Plug & Play– Plugged in devices identify themselves– Device Manager will download appropriate bundle

• Matching process for best driver

• Extendable– Driver Selector, Driver locator


Device Access 1.1

Locatorbundle

Locatorbundle

DeviceManager

DeviceManager

DeviceDevice

A deviceA device

DriverLocator

DriverLocator

selectorbundle

selectorbundle

DriverSelector

DriverSelector

DriverDriver

References to install

selects attach


Device Access

IEEE1394B

Interface Networkbundle

DriverLocator

DriverLocator

TV

7. attach

4. find bundle location

5. Install bundle

2. register

Camera1. Insert camera

9. Select camera

8. Register camera

10. Show camera on TV

3. Select device

DeviceManager

SonyCCD654

Driver 6. register

TVbundle

Camera

Device


org.osgi.service.cm v1.0Configuration Admin Service

• Configures bundles– At startup, or any later moment

• Maintains a repository of configurations– Local– Management system

• Configurations are key/value pairs– Typed with Meta Types

• Can be extended with plugins


Configuration Admin

clientbundle

clientbundle

ConfigurationAdmin impl

ConfigurationAdmin impl

ConfigurationAdmin

ConfigurationAdmin

Configurationbundle

Configurationbundle

ManagedService

ManagedService

clientbundle

clientbundle

ManagedServiceFactory

ManagedServiceFactory

ConfigurationConfiguration

1

11

0..n

ConfigurationPlugin

ConfigurationPlugin

Plugin implPlugin impl

ConfigurationException

ConfigurationException


org.osgi.service.metatype V1.0Meta Typing

• Data Descriptors for generic editors– Configurations, Properties

• Supports– Basic types like String, Integer, Byte, Short …– Arrays and Vectors

• Uses LDAP Objectclass, attribute model

• Can be localized for different languages

• General validation support


Meta Typing Class Diagram

MetaTypeProvider

MetaTypeProvider

ObjectClassDefinition

ObjectClassDefinition

AttributeDefinition

AttributeDefinition

1..n

1

1 1..n

LocalePID


org.osgi.service.prefs v1.0Preferences Service

• Simple hierarchical model like Windows Registry

• Uses simple hierarchical names– /bundle/121/httpport=81

• Different trees– Multiple named trees per bundle– One system tree

• Storage can be local or on management system


org.osgi.service.prefs v1.0Preferences Service

root Named or System

c2 /c2

d1

c1

/c1/d2

foo=8bar=9lex=‘acme’

d2

d1

d1

foo=8bar=9lex=‘acme’

d2

properties /c1/d2

/c1/d2/d1/d2

properties /c1/d2/d1/d2


Preferences Class Diagram

BackingStoreException

BackingStoreException a bundlea bundle

PreferencesService

PreferencesService

Bundlepreferences

Bundlepreferences

Service impl.Service impl.

Preference Node impl.

Preference Node impl.

PreferencesPreferences

nodes0..n

0..n

1

1

0..n

1

1

1

Root user nodes

Root system node

User name


org.osgi.service.useradmin v1.0User Admin Service

• Repository of users

• Maintains data for authentication and other purposes– Private keys, passwords, bio-profile, User Preferences

• Powerful role based authorization model– Users, group of users, and groups of groups

• Administrative functions


User Admin Class Diagram

User admin impl

User admin impl

UserAdminListener

UserAdminListenerUserAdminUserAdminRoleRole

UserUser

GroupGroup

Role implRole impl

User implUser impl

Group implGroup impl

UserAdminPermission

UserAdminPermission

User name

RequestAuthenticator

RequestAuthenticator

User Listenerimpl.

User Listenerimpl.Action implAction impl

AuthorizationAuthorization UserAdminEvent

UserAdminEvent

authenticate

Consult for authorization

Has roles

Perform action

Receiveevents

Send event

Basic member

Requiredmember


Wire Admin Service (R3)

• Connects Producer services to Consumer services via Wire object

• Wire objects have properties for configuration

WireAdminWireAdmin

ProducerProducer ConsumerConsumerWireWire


Position, Measurement, State

• Support classes for Wire Admin

• Position– Supports GPS like position

• Measurement– SI measurement system to prevent calculation errors– Error calculations– Timestamp

• State


Start Levels (R3)

• Allows Management Agent to control startup/shutdown sequence of installed bundles

• Supports many levels

• System service, implemented by Framework


URL Stream & Content

• Manages the URLStreamHandlerFactory and URLContentHandlerFactory of Java– These factories can only be set once so the

Framework must manage them

• Bundles can register a URLStreamHandlerService or ContentHandler

• The Framework will automatically add these to the standard set


Universal Plug ‘n Play (R3)

• Popular UPnP specifications adapted to OSGi Service Platform

• Makes it very easy to write a UPnP control point or device

• Involves registering a simple UPnPDevice service


Jini (R3)

• Defined how Jini devices can cooperate with an OSGi service platform

• Service Platform very good environment for Jini services, but

• Security issues


Execution Environment (R3)

• OSGi defined 2 execution environments

• Minimal– Intended for really small devices

• Foundation Profile– Adapted from JCP’s Foundation Profile

• Finally!


IO Connector Service (R3)

• Adopted J2ME javax.microedition.io package

• Process in JCP is intended to make this stand-alone

• Connection type + address selected by a single string

• Connection interfaces allows client code to adapt to different schemes– Datagram, Sockets, Servers


XML Parser Service

• Allows different bundles to register an XML parser

• Supports finding “best” parser for a specific application

• Based on standard Java JAR service


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