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 valueOf() {
        final AlarmId id = AlarmId.alarmId(DEVICE_ID, UNIQUE_ID_1);
        assertEquals("incorrect valueOf", id, ID_A);
    }