Package org.roaringbitmap
Class ParallelAggregation
- java.lang.Object
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- org.roaringbitmap.ParallelAggregation
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public class ParallelAggregation extends java.lang.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();
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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.
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Constructor Summary
Constructors Constructor Description ParallelAggregation()
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Method Summary
Modifier and Type Method Description static java.util.SortedMap<java.lang.Short,java.util.List<Container>>
groupByKey(RoaringBitmap... bitmaps)
Groups the containers by their keysstatic RoaringBitmap
or(RoaringBitmap... bitmaps)
Computes the bitwise union of the input bitmapsstatic RoaringBitmap
xor(RoaringBitmap... bitmaps)
Computes the bitwise symmetric difference of the input bitmaps
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Method Detail
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groupByKey
public static java.util.SortedMap<java.lang.Short,java.util.List<Container>> groupByKey(RoaringBitmap... bitmaps)
Groups the containers by their keys- Parameters:
bitmaps
- input bitmaps- Returns:
- The containers from the bitmaps grouped by key
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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
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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
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