Package org.apache.druid.frame.key

Class FrameComparisonWidgetImpl

java.lang.Object

org.apache.druid.frame.key.FrameComparisonWidgetImpl

All Implemented Interfaces:

FrameComparisonWidget

@NotThreadSafe
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	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, RowSignature signature, List<KeyColumn> keyColumns, List<FieldReader> keyColumnReaders)	Create a FrameComparisonWidget for the given frame.
boolean	hasNonNullKeyParts(int row, int[] keyParts)	Whether particular key parts in a particular row are non-null.
RowKey	readKey(int row)	Creates RowKey from a row in the frame.

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,
                                               RowSignature signature,
                                               List<KeyColumn> keyColumns,
                                               List<FieldReader> keyColumnReaders)

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

Parameters:

frame - frame, must be FrameType.ROW_BASED

signature - signature for the frame

keyColumns - columns to sort by

keyColumnReaders - readers for key columns

readKey

public RowKey readKey(int row)

Creates RowKey from a row in the frame. See the layout of the RowKey

Specified by:

readKey in interface FrameComparisonWidget

hasNonNullKeyParts

public boolean hasNonNullKeyParts(int row,
                                  int[] keyParts)

Description copied from interface: FrameComparisonWidget

Whether particular key parts in a particular row are non-null. When NullHandling.replaceWithDefault(), default values (like empty strings and numeric zeroes) are considered null for purposes of this method. This behavior is inherited from FieldReader.isNull(Memory, long) and enables join code to behave similarly in MSQ and native queries.

Specified by:

hasNonNullKeyParts in interface FrameComparisonWidget

Parameters:

row - row number

keyParts - parts to check

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. Comparison considers null to be equal to null. Callers that need to determine if key parts are null (perhaps because they *don't* want to consider null to be equal to null) should use FrameComparisonWidget.hasNonNullKeyParts(int, int[]) to check the relevant parts.

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 sort key, 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. Comparison considers null to be equal to null. Callers that need to determine if key parts are null (perhaps because they *don't* want to consider null to be equal to null) should use FrameComparisonWidget.hasNonNullKeyParts(int, int[]) to check the relevant parts.

Specified by:

compare in interface FrameComparisonWidget