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| <head> |
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| <title>The Command Line Processor Plugin: ArgumentProcessor</title> |
| </head> |
| |
| <body> |
| <h1>The Command Line Processor Plugin: ArgumentProcessor</h1> |
| |
| <h2 id="definition">What is an ArgumentProcessor?</h2> |
| |
| <p> |
| An <code class="code">ArgumentProcessor</code> is a parser of command line argument which is then |
| call before and after the build file is being parsed. Third party libraries may then be able to have |
| custom argument line argument which modify Ant behaviour. |
| </p> |
| |
| <p> |
| An <code class="code">ArgumentProcessor</code> is called each time Ant parse an unknown argument, |
| an <code class="code">ArgumentProcessor</code> doesn't take precedence over Ant to parse already |
| supported options. It is then recommended to third party <code class="code">ArgumentProcessor</code> |
| implementation to chose specific 'enough' argument name, avoiding for instance one letter arguments. |
| </p> |
| |
| <p> |
| It is also called at the different phases so different behaviour can be implemented. It is called |
| just after every arguments are parsed, just before the project is being configured (the build file |
| being parsed), and just after. Some of the methods to be implemented return a boolean: |
| if <q>true</q> is returned, Ant will terminate immediately, without error. |
| </p> |
| |
| <p> |
| Being called during all these phases, an <code class="code">ArgumentProcessor</code> can just print |
| some specific system properties and quit (like <kbd>-diagnose</kbd>), or print some specific |
| properties of a project after being parsed and quit (like <kbd>-projectHelp</kbd>), or just set some |
| custom properties on the project and let it run. |
| </p> |
| |
| <h2 id="repository">How to register it's own ArgumentProcessor</h2> |
| |
| <p>First, the <code class="code">ArgumentProcessor</code> must be an implementation |
| of <code class="code">org.apache.tools.ant.ArgumentProcessor</code>. |
| </p> |
| |
| <p>Then to declare it: create a |
| file <samp>META-INF/services/org.apache.tools.ant.ArgumentProcessor</samp> which contains only one |
| line the fully qualified name of the class of the implementation. This file together with the |
| implementation class need then to be found in Ant's classpath. |
| </p> |
| </body> |
| </html> |