Package org.roaringbitmap

Class ParallelAggregation

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

Modifier and Type	Method	Description
static SortedMap<Character,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 Details

ParallelAggregation

public ParallelAggregation()

Method Details

groupByKey

public static SortedMap<Character,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