Combiner (OpenRefine 4.0-SNAPSHOT API)

Type Parameters:

T -

All Superinterfaces:

Serializable

All Known Subinterfaces:

RecordAggregator<T>, RowAggregator<T>

All Known Implementing Classes:

AllFacetsAggregator, ExpressionValueFacetAggregator, FacetAggregator, NumericFacetAggregator, RowInRecordAggregator, ScatterplotFacetAggregator, StringFacetAggregator, StringValuesFacetAggregator, TextSearchFacet.TextSearchAggregator, TimeRangeFacetAggregator
```
public interface Combiner<T>
extends Serializable
```
Represents a commutative and associative function to combine aggregation states. This is mostly used to aggregate facet statistics across partitions.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`T`	`sum(T first, T second)`	Merges two facet statistics from the same facet, computed on different sets of rows.

- Method Detail
  - sum
```
T sum(T first,
      T second)
```
    Merges two facet statistics from the same facet, computed on different sets of rows. This generally amounts to summing all the statistics internally. This function is required to be associative: sum(a, sum(b, c)) == sum(sum(a, b), c)
    
    Returns:
    
    the sum of both facet statistics