AggsHandleFunction (Flink : 2.0-SNAPSHOT API)

All Superinterfaces:

AggsHandleFunctionBase, Function, Serializable
```
public interface AggsHandleFunction
extends AggsHandleFunctionBase
```
The base class for handling aggregate functions.
It is code generated to handle all AggregateFunctions together in an aggregation.
It is the entry point for aggregate operators to operate all AggregateFunctions.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`RowData`	`getValue()`	Gets the result of the aggregation from the current accumulators.
`void`	`setWindowSize(int windowSize)`	Set window size for the aggregate function.

Methods inherited from interface org.apache.flink.table.runtime.generated.AggsHandleFunctionBase
accumulate, cleanup, close, createAccumulators, getAccumulators, merge, open, resetAccumulators, retract, setAccumulators

- Method Detail
  - getValue
```
RowData getValue()
          throws Exception
```
    Gets the result of the aggregation from the current accumulators.
    
    Returns:
    
    the final result (saved in a row) of the current accumulators.
    
    Throws:
    
    Exception
  - setWindowSize
```
void setWindowSize(int windowSize)
```
    Set window size for the aggregate function. It's used in batch scenario to set the total rows of the current window frame. More information for window frame: https://docs.oracle.com/cd/E17952_01/mysql-8.0-en/window-functions-frames.html
    We may need to set the value for some window functions may require the total rows of current window frame to do calculation. For example, the function PERCENT_RANK need to know the window's size, and the SQL looks like: SELECT PERCENT_RANK() OVER ([ partition_by_clause] order_by_clause).