public boolean grantRole(String roleName, String userName,
      PrincipalType principalType, String grantor, PrincipalType grantorType,
      boolean grantOption) throws HiveException {
    try {
      return getMSC().grant_role(roleName, userName, principalType, grantor,
        grantorType, grantOption);
    } catch (Exception e) {
      throw new HiveException(e);
    }
  }
Get all existing role names.

@return List of role names.
@throws HiveException
ql/src/java/org/apache/hadoop/hive/ql/metadata/Hive.java