OSGi Users' Forum UK - OSGi Release 4 v4.2 Spec Overview - Peter Kriens

Peter Kriens
OSGi Evangelist

OSGi Next
dinsdag 14 juli 2009

OSGi Service Platform
Core Specification


Planning 4.2

• Core released for approval June 10
• Working on the ﬁnal draft for
Compendium as we speak
• Compendium : July 10
• Enterprise Release Autumn
• Residential Release Spring 2010


Legend


Legend
Bundle
A

Bundle
B


Legend
Bundle
A

Service

Bundle
B


Legend
Bundle
A

getService

Service
registerService

Bundle
B


Legend
Bundle
A

getService

Bundle
Service C
registerService

Bundle
B


Legend
Bundle
A

getService

Bundle
Service addServiceListener
C
registerService

Bundle
B


Legend
Bundle
A

getService
Call/Dependency
Bundle
Direction
Service addServiceListener
C
registerService

Bundle
B


Core

• Launching
• Bundle Tracker
• Bundle-License Header
• Service Hooks
• Negative Permissions


Launching

• To be inside a framework …
• Or outside a framework ...
• That’s the question!


Launching

• Standardizes launching different
frameworks
• Will enable generic launchers
• Allows you to embed a framework in your
application!


Launching
Map<String,String> p = new HashMap<String,String>();
List<String> impls = getMetaInfServices(
loader, FrameworkFactory.class.getName());
if (impls.size() != 1)
throw new RuntimeException(
"Too many frameworks: "+ impls);

Class<?> clazz = loader.loadClass(impls.get(0));
FrameworkFactory factory = (FrameworkFactory) clazz
.newInstance();

Framework fw = factory.newFramework(p);
Bundle b = fw.installBundle( “http://.../load/…”);
b.start();


Bundle Tracker
• Simple tool a la Service Tracker to track
bundles
• Very useful for extenders
• Bundles that provide additional
functionality based on data in a bundle
• Tracks a set of states
• Handles all concurrency issues


Service Hooks

• FindHook
• Intercept getServiceReference(s)
• EventHook
• Intercept Service Event delivery
• ListenerHook
• Find out who is listening to what


Service Hooks
Bundle
A

Bundle
B


Service Hooks
Bundle
A

Proxy
Bundle

Bundle
B


Service Hooks
Bundle
A

FindHook Proxy
EventHook Bundle

Bundle
B


Service Hooks
Bundle
A
ListenerHook

FindHook Proxy
EventHook Bundle

Bundle
B


Negative Permissions

• Java 2 Permissions are only positive
• That is, you grant a permission P
• PackagePermission(com.acme,IMPORT)
• Very hard to say, all permissions except P
• Lack of deny permissions


Negative Permissions

DENY {
[...BundleSignerCondition "cn=*, o=ACME" "!" ]
(...PackagePermission "com.acme.secret.*"
"import,exportonly" )
}
ALLOW {
(...PackagePermission "*" "*" )
}


Compendium

• Initial Provisioning
• Bundle Tracker
• Declarative Services
• Remote Services
• Blueprint Extender


Remote Services

• RFC 119
• Formerly Distributed OSGi
• Distribution Software uses services to:
• Maps a service to/from a remote system
• Uses a service to abstract a
communication endpoint


Remote Services

Distribution Distribution
Provider Provider

X’

Bundle
B


Remote Services

X Provider Provider

X’

Bundle
B


Remote Services
Bundle
A

X Provider Provider

X’

Bundle
B


Remote Services
Bundle
A

X Provider Provider

exports
X’

Bundle
B


Remote Services
Bundle
A

X Provider Provider

exports imports
X’

Bundle
B


Remote Services
Bundle
A

X Provider Provider

exports imports
X’

Bundle
B
Framework 1 Framework 2


Remote Services
• Service Properties define the interaction
• Intents specify the required/provided
capabilities
• Filters used to match
• Service Component Architecture (SCA)
• Interaction specified, not mandated
• Flexible configuration options


Service Properties
Distribution Provider
<other properties> <other properties>

service.exported.intents

service.intents service.exported.intents

service.exported.intents.extra service.imported

service.exported.interfaces objectClass

service.exported.configs service.imported.configs

remote.intents.supported
remote.configs.supported



Service Properties
Distribution Provider
<other properties> <other properties>

service.exported.intents

service.intents service.exported.intents

service.exported.intents.extra service.imported

service.exported.interfaces objectClass

service.exported.configs service.imported.configs

endpoint

remote.intents.supported
remote.configs.supported



Blueprint Extender
• RFC 124
• Provides Spring DM Functionality
• Blueprint Extender uses XML deﬁnitions in
bundle to create & wire application objects
• Namespace Handler services, not yet :-(
• Provides damping
• Proxies services


Blueprint Extender

XML


Blueprint Extender

Blueprint
XML
Container


Blueprint Extender

Blueprint
XML
Container

BeanMetadata

ServiceMetadata

Reference
Metadata


Blueprint Extender

Blueprint
XML
Container

BeanMetadata Bean

ServiceMetadata

Reference
Metadata


Blueprint Extender

Blueprint
XML
Container

BeanMetadata Bean

ServiceMetadata Service

Reference
Metadata


Blueprint Extender

Blueprint
XML
Container

BeanMetadata Bean


Reference
Metadata Reference


Blueprint Extender
Application
Objects

Blueprint
XML
Container

BeanMetadata Bean


Reference
Metadata Reference


Metadata

Null NonNull Props
Metadata Metadata Metadata

IdRef Value Component Collection Map
Metadata Metadata Metadata Metadata Metadata

Ref Map
Metadata Entry

Service
Bean Service
Reference Target
Metadata Metadata
Metadata

Ref
Reference Bean Bean
Collection
Metadata Property Argument
Metadata

Registration
Listener
Listener


Damping Reference

service
object

service
App proxy object

service
object


Damping Reference

service
object

App proxy

service
object


Damping Ref-list

service
proxy object

service
App List proxy object

service
proxy object


Enterprise

• Transactions
• JDBC Database Access
• JMX
• JNDI
• JPA
• Connectors


Experimental

• TSL
• Nested Frameworks
• OBR


TSL

• A Tiny Script Language
• Feels like a shell
• Acts like a script language
• Uses reﬂection, but simpliﬁes syntax
• No new commands
• Will become Felix project


TSL
Telnet Console ...
Shell Shell Shell

OSGi Command
Convert. Shell
Converter
ThreadIO
Eclipse TSL Thread
Convert. Impl IO

*
Felix osgi.command.name=xxx
Convert. osgi.command.function=yyy

Frame
Basic ...
Work
Cmnds Cmnds
Cmnds


TSL
$ echo Hello World
Hello World
$ echo <bundle 1>

initial@reference:file:org.eclipse.osgi.util_3.1.200.v200
70605.jar/ [1]

$ ls
eclipse
eclipse.ini
load
runner

$ ls /Ws
aQute
felix-trunk
osgi
osgi-books


TSL
$ <bundle 6> headers
Tool Bnd-0.0.169
Bundle-Activator aQute.fileinstall.FileInstall
Export-Package aQute.fileinstall ...
Created-By 1.6.0_01 (Sun Microsystems Inc.)
Bnd-LastModified 1184160147361
Bundle-Version 1.3
Bundle-ManifestVersion2
Manifest-Version 1.0
Import-Package aQute.fileinstall, ...
Bundle-Name biz.aQute.fileinstall
Bundle-Description This bundle watches a ....
Bundle-SymbolicName biz.aQute.fileinstall


TSL
$ help={each <<$it class> declaredmethods> {$it name }}
aQute.shell.runtime.Closure@90a284
$ help <bundle 6>
loadClass
getResource
...
checkLoader
closeBundleLoader
getLoaderProxy

$ echo $exception
E: java.lang.NullPointerException
$ echo $exception
java.lang.NullPointerException
$ $exception printstacktrace
$ // the output is temporarily on reall stderr ...


Nested Frameworks
• Application Server Vendors want scoping of
applications …
• Basic Idea OSGi is:
• The Application == the set of installed
bundles
• Compromise:
• All Frameworks to be nested


Nested Frameworks
System
Bundle

Framework P


Nested Frameworks
System
Bundle

Composite
Bundle

Framework P


Nested Frameworks
Framework C
System
Bundle

Composite
Bundle

Framework P


Nested Frameworks
Framework C
System
Bundle System
Bundle

Composite
Bundle

Framework P


Nested Frameworks
Framework C
System
Bundle System
Bundle

Composite Surrogate
Bundle Bundle

Framework P


Nested Frameworks
Framework C
System
Bundle System
Bundle

Composite Surrogate
Bundle Bundle

App
Bundle
A
Framework P


Nested Frameworks
Framework C
System
Bundle System
Bundle

Composite Surrogate
Bundle Bundle App
Bundle
B

App
Bundle
A
Framework P


Java Modularity


Java Modularity

294

Java Modularity

294
7

Java Modularity

42

Java Modularity

module


Java Modularity
module class Foo {}

public class Bar {
module int foo() {}
}

module interface Baz {}


Java Modularity

Visibility
vs
Accessibility


Visibility

Class Class
S T


Visibility

Module
System
Class Class
S T


Accessibility

public

module

package

private


Accessibility

Class
S


Accessibility

Class Class
S T

class


Accessibility

Class Class
S T

class

Class
U
package


Accessibility
module
Class
V

Class Class
S T

class

Class
U
package


Accessibility
module
Class
V

Class Class Class
W S T

class

Class
U
package


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


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

No Java™
Standard for
Modules!

OSGi Modules: Bundle
= Module
Bundle

module


OSGi Modules: Bundle
= Multiple Modules
Bundle

module A

module B


OSGi Modules:
Modules Cross Bundles
Bundle A Bundle B

module


OSGi Modules: Nested?

Bundle

module A

module B


Module Dependencies
Bundle A Bundle B

module A module B


Module Dependencies
Bundle A Bundle B

module A module B
requires

provides

permits


Module Dependencies

?
Bundle A Bundle B

module A module B
requires

provides

permits


Containers?

π 3.14

Containers?

π
JL S 3.14

Containers?

π
JL S 3.14
JV M


Containers?


Containers?
container com.acme


Containers?
container com.acme
module com.acme.foo;


Containers?
container com.acme
module bar;


Containers?
container com.acme
module bar;

module com.acme.foo; module com.acme.foo;
module bar; module ﬁz;
private package one; public package one;


Containers?
container com.acme
module bar;

private package one; public package one;

package one; package two;
import module ﬁz;
module class A {} class B {}


OSGi Users' Forum UK - OSGi Release 4 v4.2 Spec Overview - Peter Kriens

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OSGi Users' Forum UK - OSGi Release 4 v4.2 Spec Overview - Peter Kriens