Package org.apache.druid.query

Interface BitmapResultFactory<T>

Type Parameters:

T - the bitmap result (wrapper) type

All Known Implementing Classes:

DefaultBitmapResultFactory

public interface BitmapResultFactory<T>

BitmapResultFactory is an abstraction that allows to record something along with preFilter bitmap construction, and emit this information as dimension(s) of query metrics. BitmapResultFactory is similar to BitmapFactory: it has the same methods with the exception that it accepts generic type T (bitmap wrapper type) instead of ImmutableBitmap. DefaultBitmapResultFactory is a no-op implementation, where "wrapper" type is ImmutableBitmap itself. BitmapResultFactory delegates actual operations on bitmaps to a BitmapFactory, which it accepts in constructor, called from QueryMetrics.makeBitmapResultFactory(BitmapFactory). Emitting of query metric dimension(s) should be done from toImmutableBitmap(Object), the "unwrapping" method, called only once to obtain the final preFilter bitmap. Implementors expectations ------------------------- BitmapResultFactory is a part of the QueryMetrics subsystem, so this interface could be changed often, in every Druid release (including "patch" releases). Users who create their custom implementations of BitmapResultFactory should be ready to fix the code of their code to accommodate interface changes (e. g. implement new methods) when they update Druid. See QueryMetrics Javadoc for more info.

See Also:

• QueryMetrics.makeBitmapResultFactory(BitmapFactory)
• QueryMetrics.reportBitmapConstructionTime(long)

Method Summary

Modifier and Type	Method	Description
T	complement(T bitmapResult, int numRows)	Delegates to BitmapFactory.complement(ImmutableBitmap, int) on the wrapped bitmap, and returns a bitmap result wrapping the resulting complement ImmutableBitmap.
T	intersection(Iterable<T> bitmapResults)	Delegates to BitmapFactory.intersection(Iterable) on the wrapped bitmaps, and returns a bitmap result wrapping the resulting intersection ImmutableBitmap.
boolean	isEmpty(T bitmapResult)	Checks that the wrapped bitmap is empty, see ImmutableBitmap.isEmpty().
ImmutableBitmap	toImmutableBitmap(T bitmapResult)	Unwraps bitmapResult back to ImmutableBitmap.
T	union(Iterable<T> bitmapResults)	Delegates to BitmapFactory.union(Iterable) on the wrapped bitmaps, and returns a bitmap result wrapping the resulting union ImmutableBitmap.
T	unionDimensionValueBitmaps(Iterable<ImmutableBitmap> dimensionValueBitmaps)	Equivalent of intersection(Iterables.transform(dimensionValueBitmaps, factory::wrapDimensionValue)), but doesn't create a lot of bitmap result objects.
T	wrapAllFalse(ImmutableBitmap allFalseBitmap)	Wraps a bitmap which is a result of BitmapFactory.makeEmptyImmutableBitmap() call.
T	wrapAllTrue(ImmutableBitmap allTrueBitmap)	Wraps a bitmap which is a result of BitmapFactory.complement(ImmutableBitmap, int) called with BitmapFactory.makeEmptyImmutableBitmap() as argument.
T	wrapDimensionValue(ImmutableBitmap bitmap)	Wraps a bitmap which designates rows in a segment with some specific dimension value.

Method Details

wrapDimensionValue

T wrapDimensionValue(ImmutableBitmap bitmap)

Wraps a bitmap which designates rows in a segment with some specific dimension value.

wrapAllFalse

T wrapAllFalse(ImmutableBitmap allFalseBitmap)

Wraps a bitmap which is a result of BitmapFactory.makeEmptyImmutableBitmap() call.

wrapAllTrue

T wrapAllTrue(ImmutableBitmap allTrueBitmap)

Wraps a bitmap which is a result of BitmapFactory.complement(ImmutableBitmap, int) called with BitmapFactory.makeEmptyImmutableBitmap() as argument.

isEmpty

boolean isEmpty(T bitmapResult)

Checks that the wrapped bitmap is empty, see ImmutableBitmap.isEmpty().

intersection

T intersection(Iterable<T> bitmapResults)

Delegates to BitmapFactory.intersection(Iterable) on the wrapped bitmaps, and returns a bitmap result wrapping the resulting intersection ImmutableBitmap.

union

T union(Iterable<T> bitmapResults)

Delegates to BitmapFactory.union(Iterable) on the wrapped bitmaps, and returns a bitmap result wrapping the resulting union ImmutableBitmap.

unionDimensionValueBitmaps

T unionDimensionValueBitmaps(Iterable<ImmutableBitmap> dimensionValueBitmaps)

Equivalent of intersection(Iterables.transform(dimensionValueBitmaps, factory::wrapDimensionValue)), but doesn't create a lot of bitmap result objects.

complement

T complement(T bitmapResult,
 int numRows)

Delegates to BitmapFactory.complement(ImmutableBitmap, int) on the wrapped bitmap, and returns a bitmap result wrapping the resulting complement ImmutableBitmap.

toImmutableBitmap

ImmutableBitmap toImmutableBitmap(T bitmapResult)

Unwraps bitmapResult back to ImmutableBitmap. BitmapResultFactory should emit query metric dimension(s) in the implementation of this method.