<!DOCTYPE html> <!-- Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at https://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> <html lang="en"> <head> <link rel="stylesheet" type="text/css" href="stylesheets/style.css"> <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>