ParallelAggregation (RoaringBitmap 0.8.1 API)

java.lang.Object
- org.roaringbitmap.ParallelAggregation

```
public class ParallelAggregation
extends Object
```
These utility methods provide parallel implementations of logical aggregation operators. AND is not implemented because it is unlikely to be profitable. There is a temporary memory overhead in using these methods, since a materialisation of the rotated containers grouped by key is created in each case. Each method executes on the default fork join pool by default. If this is undesirable (it usually is) wrap the call inside a submission of a runnable to your own thread pool.
```
 

       //...

       ExecutorService executor = ...
       RoaringBitmap[] bitmaps = ...
       // executes on executors threads
       RoaringBitmap result = executor.submit(() -> ParallelAggregation.or(bitmaps)).get();
 
 
```

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`ParallelAggregation.ContainerCollector`	Collects containers grouped by their key into a RoaringBitmap, applying the supplied aggregation function to each group.
`static class`	`ParallelAggregation.OrCollector`	Collects a list of containers into a single container.

Constructor Summary

Constructors
Constructor Description

ParallelAggregation()

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static SortedMap<Short,List<Container>>`	`groupByKey(RoaringBitmap... bitmaps)`	Groups the containers by their keys
`static RoaringBitmap`	`or(RoaringBitmap... bitmaps)`	Computes the bitwise union of the input bitmaps
`static RoaringBitmap`	`xor(RoaringBitmap... bitmaps)`	Computes the bitwise symmetric difference of the input bitmaps

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - ParallelAggregation
```
public ParallelAggregation()
```
- Method Detail
  - groupByKey
```
public static SortedMap<Short,List<Container>> groupByKey(RoaringBitmap... bitmaps)
```
    Groups the containers by their keys
    
    Parameters:
    
    bitmaps - input bitmaps
    
    Returns:
    
    The containers from the bitmaps grouped by key
  - or
```
public static RoaringBitmap or(RoaringBitmap... bitmaps)
```
    Computes the bitwise union of the input bitmaps
    
    Parameters:
    
    bitmaps - the input bitmaps
    
    Returns:
    
    the union of the bitmaps
  - xor
```
public static RoaringBitmap xor(RoaringBitmap... bitmaps)
```
    Computes the bitwise symmetric difference of the input bitmaps
    
    Parameters:
    
    bitmaps - the input bitmaps
    
    Returns:
    
    the symmetric difference of the bitmaps