OSGi and Java Modularity

transcript

OSGi &Java Modularity

Jazoon 2009, Zürich

by Peter Kriens

donderdag 25 juni 2009

Application Complexity

Assembly

Structured Programming

Assembly

Object Oriented Programming

Assembly

Object Oriented Programming

Service Oriented Programming?

Application

Extensions

Application

Foundation

Java VM

Convenience

Something

Application

Extensions

Application

Foundation

Java VM

Convenience

Something

CoreJava VM

log4j barcode4j axis batik commons

derbyfopezmorphfreemarkerhttpunit

jakarta jcl json jdbm jdom

jenks jpos18 jython looks lucene

mail mx4j naming jetty poi

resolver rome serializer servlets tomcat

velocity

ws-commons

wsdl4j

xerces

xmlgraphics

xmlrpc

xmlapis

geronimo

guiapp hhfacility manufact. marketing minerva

accounting assetmaint

catalinacommon

oagis order

ebaycontent

datafile

ecommerce

entity

googlebase

Application layer

widget

minilang party pos. product workeffort workflow …

sunjce_prov.pluginjssejcert dnsns ..

Application

Extensions

Application

Foundation

Java VM

Convenience

Something

CoreJava VM

log4j barcode4j axis batik commons

derbyfopezmorphfreemarkerhttpunit

jakarta jcl json jdbm jdom

jenks jpos18 jython looks lucene

mail mx4j naming jetty poi

resolver rome serializer servlets tomcat

velocity

ws-commons

wsdl4j

xerces

xmlgraphics

xmlrpc

xmlapis

geronimo

guiapp hhfacility manufact. marketing minerva

accounting assetmaint

catalinacommon

oagis order

ebaycontent

datafile

ecommerce

entity

googlebase

Application layer

widget

minilang party pos. product workeffort workflow …

sunjce_prov.pluginjssejcert dnsns ..

by Damoiselle de Pique

Was Pollock an Early OOProgrammer?

modularity

low coupling,

low coupling,high cohesion &

low coupling,

encapsulationhigh cohesion &

How Do WeHandle ThisComplexity

in Java?

Visibilityvs

Accessibility

Visibility

ClassS

ClassT

Visibility

ClassS

ClassT

Visibility

ClassS

ClassT

Visibility

ClassS

ClassT

Visibility

ClassS

ClassT

ModuleSystem

Hierarchical Class Loaders

app app

Hierarchical Class Loaders

app app

custvisibility

Context Class Loaders

app app

Thread -> ContextClassLoader

app app

Thread -> ContextClassLoader

Accessibility

public

package

module

private

module

package

Accessibility

ClassS

ClassT

ClassW

Class U

ClassV

Java VM

barcode4j

commons

ezmorph

freemarker

httpunit

jakarta

jpos18

jython

lucene

naming

resolver

serializer

servlets

tomcat

velocity

ws-commons

wsdl4j

xerces

xmlgraphics

xmlrpc

xmlapis

geronimo

guiapp

hhfacility

manufact.

marketing

minerva

accounting

assetmaint

catalina

common

content

datafile

ecommerce

entity

googlebase

widget

minilang

product

workeffort

workflow

sunjce_prov.

plugin

BeginHere

Java VM

barcode4j

commons

ezmorph

freemarker

httpunit

jakarta

jpos18

jython

lucene

naming

resolver

serializer

servlets

tomcat

velocity

ws-commons

wsdl4j

xerces

xmlgraphics

xmlrpc

xmlapis

geronimo

guiapp

hhfacility

manufact.

marketing

minerva

accounting

assetmaint

catalina

common

content

datafile

ecommerce

entity

googlebase

widget

minilang

product

workeffort

workflow

sunjce_prov.

plugin

ClassNot

FoundException

BeginHere

import exportprivate

Split Packages

package com.foo: X, Y

package com.foo: X, Y, Z

Split Packages

2package com.foo: X, Z

Versioning

package com.bar: A,B,C;2.0

package com.bar: A;2.0

package com.foo: X, Z

Versioning

Private Packages

package com.private: G

package com.private: G,H,I

Private Packages

package com.private: G

package com.private: G,H,I

Private Packages

How Do WeHandle ThisComplexity

in Java?

We Don’t ...

OS + Hardware

Execution Environment

Module

Life Cycle

Service

SECURITY

Applications(bundles)

Execution Environment

CLDC/MIDP

J2SE 1.3, 1.4,

5, 6, ...CDC/FP

OSGiMin.

Kim Scarborough

Module Layer

Import, Export, Private

Bundle A

Bundle B

q-[1.2,1.8)

import export

private

Bundle A

Bundle B

q-[1.2,1.8)

import

imports

export

private

Bundle A

Bundle B

q-[1.2,1.8)

import

imports

exports

export

private

Bundle A

Uses ConstraintsBundle B

q-[1.2,1.8)

Bundle A

Bundle DBundle C

r;2.0r;1.0

q-[1.2,1.8)

imports

Bundle A

Bundle DBundle C

r;2.0r;1.0

q-[1.2,1.8)

imports

exports

Bundle A

Bundle DBundle C

r;2.0r;1.0

q-[1.2,1.8)

imports

exports

Bundle A

Bundle DBundle C

r;2.0r;1.0

SystemLoader

ExtensionLoader

Application BLoader

CustomLoader

SystemLoader

ExtensionLoader

Application BLoader

CustomLoader

SystemLoader

ExtensionLoader

FrameworkLoader

Application BLoader

CustomLoader

Bundle G

Bundle C

Bundle A

Bundle B

Bundle F

Bundle E

Bundle D

Life Cycle Layer

INSTALLED

RESOLVED

UNINSTALLED

ACTIVE

STOPPING

STARTING

BundleX

BundleX-v2

BundleB

MANAGE-MENT

BUNDLE

BundleA

Systembundle

Service Layer

Services

BundleA

BundleB

register get

notify

defined ininterface/class

Services

void foo() {…}

…s.foo()…

interface Foo { void foo();}

Services Solve Class Loader

Problems!donderdag 25 juni 2009

Security

Real Code!

package com.acme;import org.osgi.framework.*;public class HelloWorld extends BundleActivator { public void start(BundleContext context) { System.out.println(“Hello World”); } public void stop(BundleContext context) { System.out.println(“Goodbye World”); }}

---------------------------------------------

Manifest: 1.0Bundle-Activator: com.acme.HelloWorldImport-Package: org.osgi.framework;version=1.3

Bundles are active entities in runtime

Is JSR 294 aMeta Module System? (Implemented by OSGi™, Jigsaw, Guice, …)

No Java™ Standard for

Modules!donderdag 25 juni 2009

Legacy

Class .forName

Bloat?donderdag 25 juni 2009

AccidentalComplexity

‘97 ‘98 ‘99 ‘00 ‘01 ‘02 ‘03 ‘04 ‘05 ‘06 ‘07 ‘08 ‘09 ‘10

bundleA-1.2

bundleB-4.1

bundleC-1.0

The ComponentFramework

Q&Adonderdag 25 juni 2009

Thanks!

OSGi and Java Modularity

Design