0
# Utility Classes
1

2
Utility interfaces and classes that support the filesystem connector's operation.
3

4
## Clock Interface
5

6
Interface for providing current time to bucketing strategies.
7

8
```java { .api }
9
public interface Clock
10
```
11

12
### Method
13

14
```java { .api }
15
long currentTimeMillis()
16
```
17

18
Returns the current time in milliseconds since Unix epoch.
19

20
**Returns:** Current time in milliseconds
21

22
## SystemClock
23

24
Default Clock implementation that uses system time.
25

26
```java { .api }
27
public class SystemClock implements Clock
28
```
29

30
### Constructor
31

32
```java { .api }
33
public SystemClock()
34
```
35

36
Creates a SystemClock that returns System.currentTimeMillis().
37

38
### Usage Example
39

40
```java
41
import org.apache.flink.streaming.connectors.fs.Clock;
42
import org.apache.flink.streaming.connectors.fs.SystemClock;
43

44
// Typically used internally by the framework
45
Clock clock = new SystemClock();
46
long currentTime = clock.currentTimeMillis();
47
```
48

49
**Note:** Clock implementations are primarily used internally by bucketing strategies and are automatically provided by the BucketingSink.