Package org.apache.druid.frame.segment.columnar

Class FrameCursorFactory

java.lang.Object

org.apache.druid.frame.segment.columnar.FrameCursorFactory

All Implemented Interfaces:

CursorFactory

public class FrameCursorFactory
extends Object
implements CursorFactory

A CursorFactory implementation based on a single columnar Frame. This class is only used for columnar frames. It is not used for row-based frames.

See Also:

the row-based version

Constructor Summary

Constructors

Constructor	Description
FrameCursorFactory(Frame frame, RowSignature signature, List<FrameColumnReader> columnReaders)

Method Summary

Modifier and Type	Method	Description
boolean	canVectorize(Filter filter, VirtualColumns virtualColumns, boolean descending)	Returns true if the provided combination of parameters can be handled by "makeVectorCursor".
Sequence<Cursor>	makeCursors(Filter filter, org.joda.time.Interval interval, VirtualColumns virtualColumns, Granularity gran, boolean descending, QueryMetrics<?> queryMetrics)	Creates a sequence of Cursors, one for each time-granular bucket (based on the provided Granularity).
VectorCursor	makeVectorCursor(Filter filter, org.joda.time.Interval interval, VirtualColumns virtualColumns, boolean descending, int vectorSize, QueryMetrics<?> queryMetrics)	Creates a VectorCursor.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FrameCursorFactory

public FrameCursorFactory(Frame frame,
                          RowSignature signature,
                          List<FrameColumnReader> columnReaders)

Method Detail

canVectorize

public boolean canVectorize(@Nullable
                            Filter filter,
                            VirtualColumns virtualColumns,
                            boolean descending)

Description copied from interface: CursorFactory

Returns true if the provided combination of parameters can be handled by "makeVectorCursor". Query engines should use this before running in vectorized mode, and be prepared to fall back to non-vectorized mode if this method returns false.

Specified by:

canVectorize in interface CursorFactory

makeCursors

public Sequence<Cursor> makeCursors(@Nullable
                                    Filter filter,
                                    org.joda.time.Interval interval,
                                    VirtualColumns virtualColumns,
                                    Granularity gran,
                                    boolean descending,
                                    @Nullable
                                    QueryMetrics<?> queryMetrics)

Description copied from interface: CursorFactory

Creates a sequence of Cursors, one for each time-granular bucket (based on the provided Granularity).

Specified by:

makeCursors in interface CursorFactory

makeVectorCursor

@Nullable
public VectorCursor makeVectorCursor(@Nullable
                                     Filter filter,
                                     org.joda.time.Interval interval,
                                     VirtualColumns virtualColumns,
                                     boolean descending,
                                     int vectorSize,
                                     @Nullable
                                     QueryMetrics<?> queryMetrics)

Description copied from interface: CursorFactory

Creates a VectorCursor. Unlike the Cursor returned by "makeCursor", there is just one of these. Hence, this method does not take a "granularity" parameter. Before calling this method, check "canVectorize" to see if the call you are about to make will throw an error or not. Returns null if there is no data to walk over (for example, if the "interval" does not overlap the data interval of this segment).

Specified by:

makeVectorCursor in interface CursorFactory