public List<MusicianPK> getMusiciansForInstrument(String instrument, boolean useNamedRegion)
{
String queryName = useNamedRegion ? "musician.byinstrument.namedregion"
: "musician.byinstrument.default";
Query query = manager.createNamedQuery(queryName);
query.setParameter(1, instrument);
@SuppressWarnings("unchecked")
List<Musician> musicians = query.getResultList();
List<MusicianPK> result = new ArrayList<MusicianPK>(musicians.size());
for (Musician musician: musicians)
{
result.add(musician.getId());
}