public RepositoryTagMap(AbstractRepository repository, String commitHash, boolean isValidate)
throws IOException {
_commitHash = commitHash;
if (commitHash == null) throw new NullPointerException();
// force loading and validation from backend
if (isValidate) repository.validateHash(commitHash);
_commit = repository.readCommit(commitHash);
String sequence = _commit.get("sequence");
if (sequence != null) _sequence = Long.parseLong(sequence);
else _sequence = 1;
_tree = repository.readTree(_commit.getTree());
_tagMap = readTagMap(repository, _tree.getHash("tags"));
}
