I could also use an API that tells me which deployment directories are available, e.g.:

Set<URL> getDeploymentDirectories();

I need this for the EAR/WAR create functionality in the jboss-as-5 plugin, because I want to throw an Exception if an EAR/WAR with the same name is already deployed. I suppose this could also be accomplished with an additional parameter to distribute(), e.g.:

DeploymentProgress distribute(String name, URL contentURL, boolean copyContent, boolean overwriteIfAlreadyExists) throws Exception;

i.e. where it would throw an exception if overwriteIfAlreadyExists=false and an app with the same name is already deployed.