private AlarmId(DeviceId id, String uniqueIdentifier) {
        super(id.toString() + ":" + uniqueIdentifier);
        checkNotNull(id, "device id must not be null");
        checkNotNull(uniqueIdentifier, "unique identifier must not be null");
        checkArgument(!uniqueIdentifier.isEmpty(), "unique identifier must not be empty");
    }
@Test
    public void testConstruction() {
        final AlarmId id1 = AlarmId.alarmId(DEVICE_ID, UNIQUE_ID_3);
        assertEquals(id1.toString(), ID_Z.toString());

        final AlarmId idString = AlarmId.alarmId(ID_STRING);
        assertEquals(id1, idString);

    }