Building a new OSGi module

  Written by The Jahia Team
   Estimated reading time:

You have multiple options to build a new OSGi module, and we will quickly present them here by starting with the easiest all the way to the most complex. Depending on your needs and skills, all of these might be interesting at some point in your projects.

Using the Digital Experience Manager Studio

The easiest way to create a new OSGi module is simply to create a new module using the Digital Experience Manager Studio that allows you to create and modify module or template projects directly from the Digital Experience Manager server development environment. It will by default use the new OSGi packaging and all you will have to do is simply customize it for your needs.

We will not give the details here on how to create a new project using the Studio, as this is already explained in detail in the Digital Experience Manager templating guide, available on the Jahia.com website.

Using a Maven Archetype

We provide a Maven archetype to get started quickly with a new project. The Maven Archetype is also used internally by the Digital Experience Manager Studio to initialize a new project. The steps below guide you through the process of creating a new project.

  1. Create a new project using a Maven Archetype:
    mvn archetype:generate -Dfilter=org.jahia.archetypes:
    (do not forget the colon at the end of the filter value)
  2. Select the following archetype:
    2: remote -> org.jahia.archetypes:jahia-module-archetype (Archetype for creating a new module project to be run on a Digital Experience Manager server)
  3. Chose the latest archetype version available from the list
  4. Enter project metadata and confirm
  5. Change into project directory and build using:
    mvn clean install

You can then open the Maven project in your favorite IDE and start building your Digital Experience Manager OSGi module.

From scratch

First and foremost, if you’re ok using the Digital Experience Manager Modules parent project, it will automatically configure both the Felix Maven Bundle Plugin and Jahia Maven Plugin to use defaults that make sense for most projects. In order to do so simply set as a parent to your Maven project:

<parent>
    <artifactId>jahia-modules</artifactId>
    <groupId>org.jahia.modules</groupId>
    <version>7.0.0.0</version>
    <relativePath/>
</parent>

If you prefer not to use Digital Experience Manager module parent project, you will have to setup the plugins yourself, as explained here.

In order to build an OSGi project, it is recommended to use the Felix Maven Bundle Plugin to help with the basic packaging. This is fairly easy to setup. First change the project’s packaging to bundle:

<packaging>bundle</packaging>

Then configure and add the plugin to the project:

<plugin>
    <groupId>org.apache.felix</groupId>
    <artifactId>maven-bundle-plugin</artifactId>
    <extensions>true</extensions>
    <configuration>
        <instructions>
            <Bundle-Name>${project.name}</Bundle-Name>
            <Bundle-SymbolicName>${project.artifactId}</Bundle-SymbolicName>
            <Bundle-Category>jahia-module</Bundle-Category>

            <Implementation-Title>${project.name}</Implementation-Title>
            <Implementation-Version>${project.version}</Implementation-Version>
            <Implementation-Vendor>${project.organization.name}</Implementation-Vendor>
            <Implementation-URL>${project.organization.url}</Implementation-URL>
            <Specification-Title>${project.name}</Specification-Title>
            <Specification-Version>${project.version}</Specification-Version>
            <Specification-Vendor>${project.organization.name}</Specification-Vendor>

            <!-- Jahia manifest attributes -->
            <Jahia-Depends>default</Jahia-Depends>
            <Jahia-Module-Type>module</Jahia-Module-Type>
            <Jahia-Root-Folder>${project.artifactId}</Jahia-Root-Folder>
            <Jahia-Source-Folders>${project.basedir}</Jahia-Source-Folders>
            <Jahia-Static-Resources>/css,/icons,/images,/img,/javascript</Jahia-Static-Resources>

            <Export-Package></Export-Package>
            <!-- uncomment if you also configure the Jahia Maven plugin jahia:dependencies goal
                                    <Import-Package>*,${jahia.plugin.projectPackageImport}</Import-Package>
                                    <Provide-Capability>${jahia.plugin.providedNodeTypes}</Provide-Capability>
                                    <Require-Capability>${jahia.plugin.requiredNodeTypes}</Require-Capability>
            -->
            <Embed-Dependency>*; scope=compile; type=!pom;
                inline=true</Embed-Dependency>
            <Embed-Transitive>true</Embed-Transitive>
            <_removeheaders>
                Include-Resource,
                Private-Package,
                Embed-Dependency,
                Embed-Transitive
            </_removeheaders>
        </instructions>
        <archive>
            <addMavenDescriptor>false</addMavenDescriptor>
        </archive>
    </configuration>
</plugin>

This is the default minimal configuration for building a Jahia OSGi module bundle.

However, there are a few things that the Felix Bundle Maven plugin cannot do, it cannot scan in non-Java resources for package uses such as:

  • JSPs
  • Taglibs
  • Groovy files
  • Spring descriptors
  • Content definitions
  • Content import files

Fortunately, we provide a new goal in the Jahia Maven Plugin that will integrate with the Felix Bundle plugin that will scan all the standard Jahia module resources for you and build the required import package statements in the Felix Bundle plugin configuration.

Here is an example of setting up the Jahia Maven Plugin to scan for dependencies:

<plugin>
    <groupId>org.jahia.server</groupId>
    <artifactId>jahia-maven-plugin</artifactId>
    <executions>
        <execution>
            <id>prepare-package-dependencies</id>
            <goals>
                <goal>dependencies</goal>
            </goals>
            <configuration>
                <contentDefinitionCapabilitiesActivated>true</contentDefinitionCapabilitiesActivated>
            </configuration>
            <phase>prepare-package</phase>
        </execution>
    </executions>
</plugin>

The plugin will generate the value for the property jahia.plugin.projectPackageImport that was already inserted in the Felix Maven Bundle Plugin configuration we had previously setup.

Now the project is ready for building, which you can simply do using:

mvn clean install