CODEWITHSUNDEEP
javamavenosgircp
hueck
hueck

Reputation: 203

Migrate existing Maven Project into an OSGI Bundle

i am new to the whole OSGi stuff and my task is to create an OSGi Bundle out from an exisitng maven project.

To get started i decided to pick the smallest part and starting with it:

Here is the pom.xml

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>
<parent>
    <artifactId>cross</artifactId>
    <groupId>net.sf.maltcms</groupId>
    <version>1.2.12-SNAPSHOT</version>
</parent>
<artifactId>cross-main</artifactId>
<packaging>jar</packaging>
<name>cross-main</name>
<dependencies>
    <dependency>
        <groupId>${project.groupId}</groupId>
        <artifactId>cross-annotations</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>${project.groupId}</groupId>
        <artifactId>cross-event</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>${project.groupId}</groupId>
        <artifactId>cross-tools</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>${project.groupId}</groupId>
        <artifactId>cross-exception</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>commons-codec</groupId>
        <artifactId>commons-codec</artifactId>
        <version>1.4</version>
    </dependency>
    <dependency>
        <groupId>${project.groupId}</groupId>
        <artifactId>cross-main-api</artifactId>
        <version>${project.version}</version>
        <exclusions>
            <exclusion>
                <artifactId>commons-logging</artifactId>
                <groupId>commons-logging</groupId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>3.0.6.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-asm</artifactId>
        <version>3.0.6.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>3.0.6.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>3.0.6.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>3.0.6.RELEASE</version>
        <exclusions>
            <exclusion>
                <artifactId>commons-logging</artifactId>
                <groupId>commons-logging</groupId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-expression</artifactId>
        <version>3.0.6.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>commons-io</groupId>
        <artifactId>commons-io</artifactId>
        <version>2.1</version>
    </dependency>
    <dependency>
        <groupId>net.sf.ehcache</groupId>
        <artifactId>ehcache-core</artifactId>
        <version>2.4.6</version>
    </dependency>
    <dependency>
        <groupId>${project.groupId}</groupId>
        <artifactId>cross-math</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>com.db4o</groupId>
        <artifactId>db4o-all</artifactId>
        <version>8.0.249</version>
    </dependency>
    <dependency>
        <groupId>net.sf.mpaxs</groupId>
        <artifactId>mpaxs-spi</artifactId>
        <version>1.6.10</version>
    </dependency>
    <dependency>
        <groupId>net.sf.mpaxs</groupId>
        <artifactId>mpaxs-server</artifactId>
        <version>1.6.10</version>
    </dependency>
</dependencies>

I did some research and found the Apache Bundle Plugin for maven and changed the pom to this

<packaging>bundle</packaging>

and added

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.felix</groupId>
            <artifactId>maven-bundle-plugin</artifactId>
            <extensions>true</extensions>
            <configuration>
                <instructions>          
                    <Bundle-SymbolicName>${pom.artifactId}</Bundle-SymbolicName>
                </instructions>
            </configuration>
        </plugin>
    </plugins>
</build>

mvn clean install went fine and i got a jar file containing the manifest, but of course the bundle could not be resolved

 BundleException: The bundle "cross-main_1.2.12.SNAPSHOT [30]" could not be resolved. Reason: Missing Constraint: Import-Package: com.db4o; version="[8.0.0,9.0.0)

To make a long story short: What are the possibiliteis to migrate a maven application into an OSGi Bundle?

Espacially how to manage the dependencys

Upvotes: 0

Views: 1716

Answers (2)

Christian Schneider
Christian Schneider

Reputation: 19626

Probably all went well in the build. The maven bundle plugin automatically creates import package statements for all packages your bundle accesses. It even looks into blueprinnt and spring configs.

So the error message you get

could not be resolved. Reason: Missing Constraint: 
    Import-Package: com.db4o; version="[8.0.0,9.0.0)"

simply means that you need to install a bundle in your container that exports these packages. So ideally the db4o jar is already a bundle. Then you can simply install it. If not then you will have to create a bundle for it.

If you use apache karaf then you can make bundles on the fly by using the wrap: protocol from pax url which works for simple cases. If you need more then you can create a maven project to wrap the jar into a bundle. In most cases this is not necessary though.

I just checked the db4o download. It contains a db4o osgi bundle that you can install in your container.

Upvotes: 2

Paulius Matulionis
Paulius Matulionis

Reputation: 23413

Your maven file seems to be correct. This BundleException your'e getting:

BundleException: The bundle "cross-main_1.2.12.SNAPSHOT [30]" could not be resolved. Reason: Missing Constraint: Import-Package: com.db4o; version="[8.0.0,9.0.0)

Is because you have to import the appropriate packages in the bundle. For e.g. I have the bundle plugin:

<plugin>
    <groupId>org.apache.felix</groupId>
    <artifactId>maven-bundle-plugin</artifactId>
    <version>2.3.7</version>
    <extensions>true</extensions>
    <configuration>
        <archive>
            <manifestEntries>
                <Build-Change-Set>${changeSet}</Build-Change-Set>
                <Build-Change-Set-Date>${changeSetDate}</Build-Change-Set-Date>
                <Build-Location>${basedir}</Build-Location>
                <Build-Machine>${env.COMPUTERNAME}</Build-Machine>
                <Build-Date>${maven.build.timestamp}</Build-Date>
            </manifestEntries>
        </archive>
        <instructions>
            <Export-Package>my.bundle.main.package.*,
            </Export-Package>
            <Import-Package>
                org.springframework.context.weaving,
                org.springframework.aop,
                org.springframework.aop.framework,
                org.aopalliance.aop,
                org.apache.cxf.bus.spring,
                com.mycompany.mypackage.that.i.am.using.classess.from,
                *
            </Import-Package>
        </instructions>
    </configuration>
</plugin>

In your bundle plugin configuration add this section:

<instructions>
    <Export-Package>your.bundle.main.package.*,
    </Export-Package>
    <Import-Package>com.db4o,
        *
    </Import-Package>
</instructions>

You can get more errors like this with the different packages missing. So make sure you add them all to your Import-Package section.

The other thing to notice is: You have to export your bundle's package if your'e using it in other bundles, and in those other bundles you have to import the package of your bundle.

Upvotes: 0

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