public DefaultArtifact(ModuleRevisionId mrid, Date publicationDate, String name, String type, String ext, Map extraAttributes) { this(mrid, publicationDate, name, type, ext, null, extraAttributes);
public DefaultArtifact(ModuleRevisionId mrid, Date publicationDate, String name, String type, String ext) { this(mrid, publicationDate, name, type, ext, null, null);
    public DefaultArtifact(ModuleRevisionId mrid, Date publicationDate, String name, String type, String ext, Map extraAttributes) {    	this(mrid, publicationDate, name, type, ext, null, extraAttributes);    }