This quickstart shows you how to create and deploy a simple OSGi Bundle.
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What is OSGi?
OSGi is a new feature to JBoss Enterprise Application Platform (Tech Preview) and JBoss AS 7. It provides standards-based modularity and micro-services as defined in the OSGi 4.2 Core Specifications. You can deploy OSGi bundles directly into the server. For more information on OSGi and on how to develop OSGi bundles, see the OSGi 4.2 Core Specification and the link:http://www.osgi.org/javadoc/r4v42[OSGi 4.2 Core Javadoc. More information on the OSGi component can be found on the JBoss OSGi project pages. |
Switch to the quickstarts/helloworld-osgi directory and instruct Maven to build and deploy the application:
mvn package jboss-as:deploy
Now, you should see the OSGi subsystem start up, and the bundle deployed and started:
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If you wish to undeploy the quickstart, or redeploy after making some changes, it’s pretty easy:
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The Helloworld OSGi quickstart in depth
The OSGi Bundle has one Java Source file, the Bundle Activator:
public class Activator implements BundleActivator {
public void start(BundleContext context) throws Exception {
System.out.println("Hello AS7 World!!");
}
public void stop(BundleContext context) throws Exception {
System.out.println("Bye AS7 World!!");
}
}
The bundle activator is very simple, and just prints out a message when the bundle starts and stops - allowing you to verify that OSGi is working properly.
Now, let’s look at the pom.xml , where we create the bundle:
<?xml version="1.0"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.jboss.as.quickstarts</groupId>
<artifactId>jboss-as-helloworld-osgi</artifactId>
<version>7.1.1.Final</version>
<packaging>bundle</packaging> 
<name>JBoss AS Quickstarts: Helloworld OSGi</name>
<description>JBoss AS Quickstarts: Helloworld OSGi</description>
<url>http://jboss.org/jbossas/osgi</url>
<licenses>
<license>
<name>Apache License, Version 2.0</name>
<distribution>repo</distribution>
<url>
http://www.apache.org/licenses/LICENSE-2.0.html
</url>
</license>
</licenses>
<properties>
<!-- Explicitly declaring the source encoding eliminates the
following message: -->
<!-- [WARNING] Using platform encoding (UTF-8 actually) to
copy filtered resources, i.e. build is platform
dependent! -->
<project.build.sourceEncoding>
UTF-8
</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.osgi</groupId> 
<artifactId>org.osgi.core</artifactId>
<version>4.2.0</version>
<scope>provided</scope> 
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<!-- This plugin takes care of packaging the
artifact as an OSGi Bundle -->
<groupId>org.apache.felix</groupId>
<artifactId>maven-bundle-plugin</artifactId> 
<version>2.3.4</version>
<extensions>true</extensions>
<configuration>
<instructions>
<!-- OSGi Manifest Metadata is specified
here -->
<!-- The Bundle SymbolicName is the same as
the artifact ID -->
<Bundle-SymbolicName>
${project.artifactId}
</Bundle-SymbolicName>
<!-- Specify the Bundle activator, which is
invoked when the Bundle is started -->
<Bundle-Activator>
org.jboss.as.quickstarts.helloworld.osgi.Activator
</Bundle-Activator>
<!-- Automatically compute all the necessary
Import-Package statements -->
<Import-Package>*</Import-Package>
<!-- This bundle does not export any
packages -->
<Export-Package />
<!-- Packages that are not exported but need
to be included need to be listed as
Private-Package -->
<Private-Package>
org.jboss.as.quickstarts.helloworld.osgi
</Private-Package>
</instructions>
</configuration>
</plugin>
<!-- JBoss AS plugin to deploy artifact -->
<plugin>
<groupId>org.jboss.as.plugins</groupId> 
<artifactId>jboss-as-maven-plugin</artifactId>
<version>7.1.1.Final</version>
<configuration>
<filename>
${project.build.finalName}.jar
</filename>
</configuration>
</plugin>
<!-- Compiler plugin enforces Java 1.6 compatibility
to remove unnecessary warnings about execution
environment in IDE -->
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.1</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
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The packaging of the maven module is set to bundle . This instructs maven and the maven-bundle-plugin to create an OSGi bundle. |
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Since the activator uses an OSGi interface, these are provided through the OSGi interfaces artifact. |
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Use the provided scope for dependencies that are either provided by the OSGi framework (i.e. JBoss Enterprise Application Platform 6 or JBoss AS 7) itself or for dependencies that are provided through separate bundles. |
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The maven-bundle-plugin is used to create a bundle. You can configure it create import and export statements, and to specify the activator in use. You can read more about the OSGi Bundle Maven Plugin on the Apache Felix site. |
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We can use the jboss-as Maven plugin to deploy the bundle to the server as usual. |
As you can see, using OSGi with JBoss Enterprise Application Platform 6 and JBoss AS 7 is pretty easy!
Creating a new OSGi bundle using Eclipse
Eclipse has built-in support for creating OSGi bundles. Eclipse is built on OSGi, therefore support for developing OSGi bundles inside Eclipse is quite extensive.
To quickly create an OSGi Bundle using Eclipse, follow these steps. In Eclipse do File New → Project → Plug-in Project:
Select as the Target Platform a Standard OSGi Framework and click Next >.
On the following page, you can specify the Bundle Symbolic Name, version, _Bundle Activator+ and some other details. You may use the defaults, or, for example, you could put the Activator in a different package, e.g. org.jboss.as.quickstarts.helloworld.osgi.Activator.
Click Next > again.
On the Templates page select the Hello OSGi Bundle template and click Finish:
After clicking Finish, the Plug-In Development perspective will open with the Manifest Editor. The Manifest Editor facilitates editing of the OSGi Metadata, such as the Imported Packages in the Dependencies tab and Exported Packages on the Runtime tab:
Click on the Activator link in the Manifest Editor to open the Bundle Activator in the Java Editor.
When you are finished making changes you can export your OSGi bundle so that it can be deployed directly. Click on File → Export → Deployable plug-ins and fragments:
You have now created an OSGi Bundle, and the JAR can be found in the plugins directory of the location specified in the screen above. You can deploy it to the server using any of the standard deployment mechanisms described in the Administration and Configuration Guide for JBoss Enterprise Application Platform 6 or the JBoss AS 7 Getting Started Guide.
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Recent Changelog
- Jan 24, 2013: Compatibility updates for asciidoctor Dan Allen
- Sep 17, 2012: Fixing jdf-78 Jason Porter
- Jul 19, 2012: Add author to the guide Pete Muir
- Jul 10, 2012: Initial import of getting started developing applications guide Pete Muir
