public Set<String> getVersions( VersionedReference reference )
        throws ContentNotFoundException
    {
        File groupDir = new File( repository.getLocation(), reference.getGroupId() );

        if ( !groupDir.exists() )
        {
            throw new ContentNotFoundException(
                "Unable to get versions using a non-existant groupId directory: " + groupDir.getAbsolutePath() );
        }

        if ( !groupDir.isDirectory() )
        {
            throw new ContentNotFoundException(
                "Unable to get versions using a non-directory: " + groupDir.getAbsolutePath() );
        }

        Set<String> foundVersions = new HashSet<String>();

        // First gather up the versions found as artifacts in the managed repository.
        File typeDirs[] = groupDir.listFiles();
        for ( File typeDir : typeDirs )
        {
            if ( !typeDir.isDirectory() )
            {
                // Skip it, we only care about directories.
                continue;
            }

            if ( !typeDir.getName().endsWith( "s" ) )
            {
                // Skip it, we only care about directories that end in "s".
            }

        }
    }

    public int getId()
    {
        return repository.getId();
    }

    public Set<ArtifactReference> getRelatedArtifacts( ArtifactReference reference )
        throws ContentNotFoundException, LayoutException
    {
        File artifactFile = toFile( reference );
        File repoDir = artifactFile.getParentFile();

        if ( !repoDir.exists() )
        {
            throw new ContentNotFoundException(
                "Unable to get related artifacts using a non-existant directory: " + repoDir.getAbsolutePath() );
        }

        if ( !repoDir.isDirectory() )
        {
            throw new ContentNotFoundException(
                "Unable to get related artifacts using a non-directory: " + repoDir.getAbsolutePath() );
        }

        Set<ArtifactReference> foundArtifacts = new HashSet<ArtifactReference>();

                VersionedReference reference = new VersionedReference();
                reference.setGroupId( artifact.getGroupId() );
                reference.setArtifactId( artifact.getArtifactId() );
                reference.setVersion( artifact.getVersion() );

                List<String> versions = new ArrayList<String>( repository.getVersions( reference ) );

                Collections.sort( versions, VersionComparator.getInstance() );

                if ( retentionCount > versions.size() )
                {
                    // Done. nothing to do here. skip it.
                    return;
                }

                int countToPurge = versions.size() - retentionCount;

                for ( String version : versions )
                {
                    if ( countToPurge-- <= 0 )