Unpacking Maven Dependencies

Unpacking a kit for inclusion in a Java library

The first time I came to do this I was new to maven and I didn’t know about the maven-dependency-plugin, so I had a hard time keeping a handle on the downloaded kit. Well, I’m back, and this time I mean business.

I’ve listed the plugins I used in something like sequential order:

maven-dependency-plugin

The maven-dependency-plugin is used to download a kit which contains a bunch of templates used in my artifact (which happens to be a Java library). I chose to bind this to the process-resources phase because nobody told me not to, but really it could have gone anywhere before the antrun execution.

{% highlight xml %} org.apache.maven.plugins maven-dependency-plugin 2.4 copy-dependency process-resources unpack

                    <groupId>com.mycompany</groupId>
                    <artifactId>some-artifact</artifactId>
                    <type>zip</type>
                    <classifier>some-classifier</classifier>
                    <version>some-version</version>
                    <overWrite>true</overWrite>
                    <outputDirectory>${project.build.directory}/template-kit</outputDirectory>
                    <excludes>**/*.inventory</excludes>

                </artifactItem>
            </artifactItems>
        </configuration>
    </execution>
</executions>

maven-antrun-plugin

I used antrun to unpack the kit to a staging directory. The working tree in the staging directory is organised in the same way as in the jar. The property ${project.build.directory} is globally set and holds the location of the target/ directory.

{% highlight xml %} maven-antrun-plugin template-unpack prepare-package run

                <copy todir="${staging}">
                    <fileset dir="${project.build.directory}/template-kit/">
                        <include name="**/some/files/to/include/*" />
                    </fileset>
                    <flattenmapper />
                </copy>

            </tasks>
        </configuration>
    </execution>
</executions>

maven-assembly-plugin

Finally the assembly plugin is is used in conjunction with the assembly descriptor (kit.xml) to jar everything up.

{% highlight xml %} maven-assembly-plugin make-assembly package single false target/classes/META-INF/MANIFEST.MF src/main/assembly/kit.xml {% endhighlight %}

The kit.xml for all the magic looks like this:

{% highlight xml %} distribution jar false target/staging/ / templates//* /*.java false {% endhighlight %}

Here’s the documentation for the maven-dependency-plugin. It’s got some jolly good examples.