InputWatermarkManager (Nemo Project 0.4 API)

All Known Implementing Classes:

MultiInputWatermarkManager, SingleInputWatermarkManager
```
public interface InputWatermarkManager
```
An interface for tracking input watermarks among multiple input streams. --edge 1--> --edge 2--> watermarkManager --(emitWatermark)--> nextOperator --edge 3-->

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`trackAndEmitWatermarks(int edgeIndex, Watermark watermark)`	This tracks the minimum input watermark among multiple input streams.

- Method Detail
  - trackAndEmitWatermarks
```
void trackAndEmitWatermarks(int edgeIndex,
                            Watermark watermark)
```
    This tracks the minimum input watermark among multiple input streams. This method is not a Thread-safe so the caller should synchronize it if multiple threads access this method concurrently. Ex) -- input stream1 (edge 1): ---------- ts: 3 ------------------ts: 6 ^^^ emit ts: 4 (edge 2) watermark at this time -- input stream2 (edge 2): ----------------- ts: 4------ ^^^ emit ts: 3 (edge 1) watermark at this time -- input stream3 (edge 3): ------- ts: 5 ---------------
    
    Parameters:
    
    edgeIndex - incoming edge index
    
    watermark - watermark emitted from the edge