------
 Sharing Assembly Descriptors
 ------
 Dennis Lundberg
 ------
 2010-11-08
 ------

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Sharing Assembly Descriptors

  So you have created an assembly descriptor that you feel is so good that you
  want to share it between several of your projects. The simplest way to solve
  this problem is to create a separate project for your assembly descriptor.
  Let's call the project <my-assembly-descriptor>.

  <<Note:>> This example has been updated for version 2.2. The previous versions
  of this example were wrong. You must follow the steps below to make your
  shared assembly descriptors work with version 2.2 or later.

* The Shared Assembly Descriptor Project

  Here's what the directory structure for that project looks like:

+---+
my-assembly-descriptor
    +-- src
    |   `-- main
    |       `-- resources
    |           `-- assemblies
    |               `-- myassembly.xml
    `-- pom.xml
+---+

  There are just two files in this project: your assembly descriptor
  <<<myassembly.xml>>> and a <<<pom.xml>>>.

  <<Note:>> Your assembly descriptors must be in the directory
  <<</src/main/resources/assemblies>>> to be available to the Assembly Plugin. 

  First let's check out the POM for the Shared Assembly Descriptor Project. It
  is quite simple:

+---+
<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>your.group.id</groupId>
  <artifactId>my-assembly-descriptor</artifactId>
  <version>1.0-SNAPSHOT</version>
  <name>Shared Assembly Descriptor</name>
</project>
+---+

  Next let's look at our shared assembly descriptor. This is just an example.
  Replace it with the assembly descriptor you want to share.

+---+
<assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/${mdoVersion}"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/${mdoVersion} http://maven.apache.org/xsd/assembly-${mdoVersion}.xsd">
  <id>my-assembly-descriptor-id</id>
  <formats>
    <format>jar</format>
  </formats>
  <fileSets>
    <fileSet>
      <includes>
        <include>pom.xml</include>
      </includes>
      <useDefaultExcludes>true</useDefaultExcludes>
    </fileSet>
    <fileSet>
      <directory>src</directory>
      <useDefaultExcludes>true</useDefaultExcludes>
    </fileSet>
  </fileSets>
</assembly>
+---+

  Run '<<<mvn install>>>' on this project to install the Shared Assembly
  Descriptor project into your local repository.


* The Project Using the Shared Assembly Descriptor

  In the project that wants to use our Shared Assembly Descriptor, you need to
  add <<<my-assembly-descriptor>>> as a dependency on the Assembly Plugin. This
  makes our assembly descriptor available for the Assembly Plugin to use.

  <<Note:>> You need to use the file name of your assembly descriptor, without
  the xml file extension, in <<<\<descriptorRef\>>>>. You can not use the id of
  your assembly descriptor. The assembly descriptor used in this example have
  the file name <<<myassembly.xml>>>, but its id is
  <<<my-assembly-descriptor-id>>>. Therefor we use <<<myassembly>>> to reference
  that assembly descriptor.

+---+
<project>
  <groupId>your.group.id</groupId>
  <artifactId>my-project</artifactId>
  <version>1.0-SNAPSHOT</version>
  <modelVersion>4.0.0</modelVersion>
  ...
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-assembly-plugin</artifactId>
        <version>${project.version}</version>
        <dependencies>
          <dependency>
            <groupId>your.group.id</groupId>
            <artifactId>my-assembly-descriptor</artifactId>
            <version>1.0-SNAPSHOT</version>
          </dependency>
        </dependencies>
        <executions>
          <execution>
            <id>make-assembly</id>
            <phase>package</phase>
            <goals>
              <goal>single</goal>
            </goals>
            <configuration>
              <!-- This is where we use our shared assembly descriptor -->
              <descriptorRefs>
                <descriptorRef>myassembly</descriptorRef>
              </descriptorRefs>
            </configuration>
          </execution>
        </executions>
      </plugin>
      ...
    </plugins>
  </build>
  ...
</project>
+---+