org.apache.druid.frame.key

Class FrameComparisonWidgetImpl

java.lang.Object

org.apache.druid.frame.key.FrameComparisonWidgetImpl

All Implemented Interfaces:

FrameComparisonWidget

public class FrameComparisonWidgetImpl
extends Object
implements FrameComparisonWidget

Implementation of FrameComparisonWidget for pairs of FrameType.ROW_BASED frames. Comparison logic in this class is very similar to RowKeyComparator, but is different because it works on Frames instead of byte[].

Method Summary

Modifier and Type	Method and Description
int	compare(int row, FrameComparisonWidget otherWidget, int otherRow) Compare a specific row of this frame to a specific row of another frame.
int	compare(int row, RowKey key) Compare a specific row of this frame to the provided key.
static FrameComparisonWidgetImpl	create(Frame frame, FrameReader frameReader, List<SortColumn> sortColumns) Create a FrameComparisonWidget for the given frame.
RowKey	readKey(int row) Returns the RowKey corresponding to a particular row.

Methods inherited from class java.lang.Object

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

Method Detail

create

public static FrameComparisonWidgetImpl create(Frame frame,
                                               FrameReader frameReader,
                                               List<SortColumn> sortColumns)

Create a FrameComparisonWidget for the given frame. Only possible for frames of type FrameType.ROW_BASED. The provided sortColumns must be a prefix of FrameReader.signature().

Parameters:

frame - frame, must be FrameType.ROW_BASED

frameReader - reader for the frame

sortColumns - columns to sort by

readKey

public RowKey readKey(int row)

Description copied from interface: FrameComparisonWidget

Returns the RowKey corresponding to a particular row. The returned key is a copy that does not reference memory of the underlying Frame.

Specified by:

readKey in interface FrameComparisonWidget

compare

public int compare(int row,
                   RowKey key)

Description copied from interface: FrameComparisonWidget

Compare a specific row of this frame to the provided key. The key must have been created with sortColumns that match the ones used to create this widget, or else results are undefined.

Specified by:

compare in interface FrameComparisonWidget

compare

public int compare(int row,
                   FrameComparisonWidget otherWidget,
                   int otherRow)

Description copied from interface: FrameComparisonWidget

Compare a specific row of this frame to a specific row of another frame. The other frame must have the same signature, or else results are undefined. The other frame may be the same object as this frame; for example, this is used by FrameSort to sort frames in-place.

Specified by:

compare in interface FrameComparisonWidget