org.apache.cassandra.db.rows

Class Rows

java.lang.Object

org.apache.cassandra.db.rows.Rows

public abstract class Rows
extends java.lang.Object

Static utilities to work on Row objects.

Field Summary

Fields

Modifier and Type	Field and Description
static Row	EMPTY_STATIC_ROW

Method Summary

Modifier and Type	Method and Description
static int	collectStats(Row row, PartitionStatisticsCollector collector) Collect statistics on a given row.
static Row.Builder	copy(Row row, Row.Builder builder)
static void	diff(RowDiffListener diffListener, Row merged, Row... inputs) Given the result (merged) of merging multiple inputs, signals the difference between each input and merged to diffListener.
static Row	merge(Row row1, Row row2, int nowInSec)
static long	merge(Row existing, Row update, Row.Builder builder, int nowInSec) Merges two rows into the given builder, mainly for merging memtable rows.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_STATIC_ROW

public static final Row EMPTY_STATIC_ROW

Method Detail

copy

public static Row.Builder copy(Row row,
                               Row.Builder builder)

collectStats

public static int collectStats(Row row,
                               PartitionStatisticsCollector collector)

Collect statistics on a given row.

Parameters:

row - the row for which to collect stats.

collector - the stats collector.

Returns:

the total number of cells in row.

diff

public static void diff(RowDiffListener diffListener,
                        Row merged,
                        Row... inputs)

Given the result (merged) of merging multiple inputs, signals the difference between each input and merged to diffListener.

Note that this method doesn't only emit cells etc where there's a difference. The listener is informed of every corresponding entity between the merged and input rows, including those that are equal.

Parameters:

diffListener - the listener to which to signal the differences between the inputs and the merged result.

merged - the result of merging inputs.

inputs - the inputs whose merge yielded merged.

merge

public static Row merge(Row row1,
                        Row row2,
                        int nowInSec)

merge

public static long merge(Row existing,
                         Row update,
                         Row.Builder builder,
                         int nowInSec)

Merges two rows into the given builder, mainly for merging memtable rows. In addition to reconciling the cells in each row, the liveness info, and deletion times for the row and complex columns are also merged.

Note that this method assumes that the provided rows can meaningfully be reconciled together. That is, that the rows share the same clustering value, and belong to the same partition.

Parameters:

existing -

update -

builder - the row build to which the result of the reconciliation is written.

nowInSec - the current time in seconds (which plays a role during reconciliation because deleted cells always have precedence on timestamp equality and deciding if a cell is a live or not depends on the current time due to expiring cells).

Returns:

the smallest timestamp delta between corresponding rows from existing and update. A timestamp delta being computed as the difference between the cells and DeletionTimes from existing and those in existing.