Updated Apache Tomcat Web Application Maven Archetypes via MuleSoft

30 Apr 2010

MuleSoft Tomcat Web App Maven Archetypes

I'm pleased to announce that MuleSoft and I have collaborated to freshen the world's two most commonly used Maven Web Application Archetypes, the maven-archetype-webapp and the wicket-archetype-quickstart.

The Motivations

These two archetypes had fallen out of date, both in terms of using the new Archetype 2.0 style metadata, as well as in the dependencies on the third-party libraries such as JUnit. Due to limited volunteer developer time, when the Maven Archetype developers moved from the 1.0 to the 2.0 branch many of the existing archetypes did not successfully make the transition. Thus, the public was having to make do by using old versions of these archetypes.

The Update

Given MuleSoft's and my keen interest in the Apache Tomcat ecosystem, including the enterprise-strength Tcat product, we set out to bring these two aging archetypes up to date. We found that easiest to do under the very open MuleForge repository & GitHub source code hosting for the near term, but we will be submitting a patch to get these improvements back into the core archetypes at Apache too.

Contributing back to community

A week into the effort, the "update" turned into a complete "rewrite" of the archetypes to reap all the benefits of the Maven Archetype Plugin's version 2.0 features.

The metadata has dramatically changed between the Maven Archetype 1.0 and 2.0 versions of the plugin. Previously, the file named archetype.xml lived in the src/main/resources/META-INF/ directory, then it was relocated to src/main/resources/META-INF/maven, and finally, in full modern 2.0 form, has been additionally renamed to src/main/resources/META-INF/maven/archetype-metadata.xml.

Similarly, variables inside source files were updated to use the ${} notation, with legacy elements like $package updated to ${package}.

The poms for the archetypes were updated from the old archetype plugin type to use the new 2.0 lifecycle extensions

The resultant archetype code is hosted at GitHub for easy viewing, consumption, technical review and forking. We'd love to get your input and improvements!

These two archetypes now represent the most pristine use of the Maven Archetype Plugin v2.0 format.

Integration Tests

We didn't want to stop at just updating the archetypes though. We wanted to make them better. So one of the most obvious ways to do that was through adding integration tests. I can't tell you how often I get asked for a good example of leveraging the Maven pre-integration-test and post-integration-test lifecycle events. Up until now, I've been relatively empty handed to respond to this request, but finally we have some reference examples.

These lifecycles are now bound to the redeployment and undeployment of the web application artifact (WAR) and the execution of a JWebUnit integration test that exercises and validates the home page on each of the JSP and Wicket flavors of web application.

Instructions for Use

We've built a wiki page showcasing the usage of this archetype which we also invite you to review and improve. In short, you can inform Maven of the new archetype catalog via a quick execution of:

mvn archetype:generate -DarchetypeCatalog=http://dist.muleforge.org/maven2/

Lastly, for those of you that prefer a video walkthrough of the usage of these two archetypes, check out our screencast demo that takes you from start to finish of working with these valuable new tools in the Maven, Tomcat, Tcat, and web application development ecosystems.

Future Goals

Like all good developers, we are always looking towards the next iteration, just as the current ones are drawing to successful close. In the next release of these archetypes, or perhaps in supplemental sibling instances, we're exploring:

  1. A zero-footprint, embedded Tcat installation that can be retrieved from a Maven repository.
  2. Profiles to allow for the integration tests to be selectively executed in a local or embedded Tomcat or Tcat installation, possibly auto-detected to activate the proper profile.
  3. Support for Maven provisioning of completed artifacts into Tcat server groups.

OSS Thanks

In closing, we want to thank the Tomcat community for founding such a great product and the Maven community for planting the seeds of these new archetypes. Java web application development is at its current fevered pitch, thanks, in large part, to these excellent tools and their communities.