In its unadorned state, Maven represents an implementation of the 80/20 rule. Using the default life-cycle mapping, Maven can build a basic project with little or no modification – thus covering the 80% case. However, in certain circumstances, a project requires special tasks in order to build successfully. Whether they be code-generation, reporting, or verification steps, Maven can integrate these custom tasks into the build process through its extensible plugin framework. Since the build process for a project is defined by the plugins – or more accurately, the mojos – that are bound to the build life cycle, there is a standardized way to inject new behavior into the build by binding new mojos at different life-cycle phases.
In this chapter, you’ve learned that it’s relatively simple to create a mojo that can extract relevant parts of the build state in order to perform a custom build-process task – even to the point of altering the set of source-code directories used to build the project. Working with project dependencies and resources is equally as simple. Finally, you’ve also learned how a plugin generated file can be distributed alongside the project artifact in Maven’s repository system, enabling you to attach custom artifacts for installation or deployment.
Many plugins already exist for Maven use, only a tiny fraction of which are a part of the default life-cycle mapping. If your project requires special handling, chances are good that you can find a plugin to address this need at the Apache Maven project, the Codehaus Mojo project, or the project web site of the tools with which your project’s build must integrate. If not, developing a custom Maven plugin is an easy next step.
Mojo development can be as simple or as complex (to the point of embedding nested Maven processes within the build) as you need it to be. Using the plugin mechanisms described in this chapter, you can integrate almost any tool into the build process.
However, remember that whatever problem your custom-developed plugin solves, it’s unlikely to be a requirement unique to your project. So, if you have the means, please consider contributing back to the Maven community by providing access to your new plugin. It is in great part due to the re-usable nature of its plugins that Maven can offer such a powerful build platform.