Package org.apache.druid.segment

Class Cursors

java.lang.Object

org.apache.druid.segment.Cursors

public class Cursors
extends Object

Constructor Summary

Constructors

Constructor	Description
Cursors()

Method Summary

Modifier and Type	Method	Description
static List<OrderBy>	ascendingTimeOrder()	Get a CursorHolder OrderBy list that contains only a ColumnHolder.TIME_COLUMN_NAME as Order.ASCENDING, classic Druid segment order.
static List<OrderBy>	descendingTimeOrder()	Get a CursorHolder OrderBy list that contains only a ColumnHolder.TIME_COLUMN_NAME as Order.DESCENDING, classic Druid segment order in reverse.
static Order	getTimeOrdering(List<OrderBy> ordering)	Return the Order of the ColumnHolder.TIME_COLUMN_NAME, based on a CursorHolder.getOrdering() or Metadata.getOrdering().
static boolean	preferDescendingTimeOrdering(CursorBuildSpec buildSpec)	Check if the first OrderBy column of CursorBuildSpec.getPreferredOrdering() is Order.DESCENDING, which allow Cursor on time ordered data to advance in descending order if possible.

Methods inherited from class java.lang.Object

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

Constructor Details

Cursors

public Cursors()

Method Details

preferDescendingTimeOrdering

public static boolean preferDescendingTimeOrdering(CursorBuildSpec buildSpec)

Check if the first OrderBy column of CursorBuildSpec.getPreferredOrdering() is Order.DESCENDING, which allow Cursor on time ordered data to advance in descending order if possible.

getTimeOrdering

public static Order getTimeOrdering(List<OrderBy> ordering)

Return the Order of the ColumnHolder.TIME_COLUMN_NAME, based on a CursorHolder.getOrdering() or Metadata.getOrdering().

ascendingTimeOrder

public static List<OrderBy> ascendingTimeOrder()

Get a CursorHolder OrderBy list that contains only a ColumnHolder.TIME_COLUMN_NAME as Order.ASCENDING, classic Druid segment order.

descendingTimeOrder

public static List<OrderBy> descendingTimeOrder()

Get a CursorHolder OrderBy list that contains only a ColumnHolder.TIME_COLUMN_NAME as Order.DESCENDING, classic Druid segment order in reverse.