Section 1.18. Pointing Maven at Source Control

1.18. Pointing Maven at Source Control

Do you use source control? Tell Maven about it, and you'll be able to generate some interesting reports described later in this book. Once you have associated your project with a source code repository, you will be able to use the Maven Source Control Management (SCM) plug-in which provides goals for updating and releasing from a version control system such as CVS or Subversion.

1.18.1. How do I do that?

You need to add a repository element to your project's project.xml. The following repository element is from the Apache Struts project, and it points to the Subversion repository available at http://svn.apache.org/repos/asf/struts/core/trunk:

<repository>   <connection>     scm:svn:http://svn.apache.org/repos/asf/struts/core/trunk   </connection>   <developerConnection>     scm:svn:https://svn.apache.org/repos/asf/struts/core/trunk   </developerConnection>   <url>http://svn.apache.org/repos/asf/struts/core/trunk</url> </repository>

The connection element tells Maven about the read-only location of the SCM. scm identifies this URL as being an SCM location, svn tells Maven that this URL will be for a Subversion repository, and the final section of the URL is the location to the project's trunk. You may also specify the developerConnection; you use this element when you need to segment your audience into people without write access to source code, and people with write access.

The url element supplies a URL that can be used to browse the repository. In the case of Struts, they have elected to point to the Subversion repository itself, as it can be browsed with a regular web browser. The Struts team could also elect to point to the ViewCVS instance configured to point to the ASF Subversion repository, which can be found at the following URL: http://cvs.apache.org/viewcvs.cgi/struts/core/trunk/?root=Apache-SVN.

When you point a project.xml file at a particular source control system, you can also specify the different versions and branches of a particular project. The following XML shows a reduced version of the versions and branches elements from the Apache Struts project.xml file:

  <versions>     <version>       <id>1.2.0</id>       <name>1.2.0</name>       <tag>STRUTS_1_2_0</tag>     </version>     <version>       <id>1.2.6</id>       <name>1.2.6</name>       <tag>STRUTS_1_2_6</tag>     </version>   </versions>      <branches>     <branch>       <tag>STRUTS_1_1_BRANCH</tag>     </branch>     <branch>       <tag>STRUTS_1_2_BRANCH</tag>     </branch>   </branches>

Versions are used by several plug-ins, such as the Announcements plug-in, which is used to create release notes for each version.

1.18.2. What about...

...CVS?

While many corporate and open source projects have switched to Subversion, some major open source projects such as JBoss have yet to make the jump to Subversion. If your project is using CVS, you will need to add a repository element similar to the repository element from the Jakarta Cactus project shown here:

  <repository>     <connection>       scm:cvs:pserver:[e-mail]:/home/cvspublic:jakarta-cactus     </connection>     <url>http://cvs.apache.org/viewcvs.cgi/jakarta-cactus/</url>   </repository>

The previous excerpt is appropriate if you are exposing your repository using CVS pserver. If you are accessing CVS over SSH, you will need to set your CVS_RSH environment variable to ssh and use the following syntax:

<repository>   <connection>     scm:cvs:pserver:[e-mail]:/home/cvspublic:jakarta-cactus   </connection>   <url>http://cvs.apache.org/viewcvs.cgi/jakarta-cactus/</url>   <developerConnection>     scm:cvs:ext:tobrien@somehost:/home/cvs/repository:modulename   </developerConnection> </repository>