For a sample custom consumer, you can checkout the archiva-consumer-plugin at the archiva sandbox in the SVN repository:
http://svn.apache.org/repos/asf/maven/sandbox/trunk/archiva/archiva-consumer-plugin
Below are the steps on how to create a custom repository consumer and plug it in Archiva:
Ex. @plexus.component role="org.apache.maven.archiva.consumers.KnownRepositoryContentConsumer" role-hint="discover-new-artifact" instantiation-strategy="per-lookup" where, role: the interface that your class implements role-hint: the lookup name of the component (your class/consumer) instantiation-strategy: how your class will be instantiated
<plugin> <groupId>org.codehaus.plexus</groupId> <artifactId>plexus-maven-plugin</artifactId> <version>1.3.5</version> <executions> <execution> <id>generate</id> <goals> <goal>descriptor</goal> </goals> </execution> </executions> </plugin>