org.apache.cassandra.thrift

Class ThriftResultsMerger

java.lang.Object

org.apache.cassandra.db.transform.Transformation<UnfilteredRowIterator>

org.apache.cassandra.thrift.ThriftResultsMerger

public class ThriftResultsMerger
extends Transformation<UnfilteredRowIterator>

Given an iterator on a partition of a compact table, this return an iterator that merges the static row columns with the other results. Compact tables stores thrift column_metadata as static columns (see CompactTables for details). When reading for thrift however, we want to merge those static values with other results because: 1) on thrift, all "columns" are sorted together, whether or not they are declared column_metadata. 2) it's possible that a table add a value for a "dynamic" column, and later that column is statically defined. Merging "static" and "dynamic" columns make sure we don't miss a value prior to the column declaration. For example, if a thrift table declare 2 columns "c1" and "c5" and the results from a query is: Partition: static: { c1: 3, c5: 4 } "a" : { value : 2 } "c3": { value : 8 } "c7": { value : 1 } then this class transform it into: Partition: "a" : { value : 2 } "c1": { value : 3 } "c3": { value : 8 } "c5": { value : 4 } "c7": { value : 1 }

Method Summary

Modifier and Type	Method and Description
UnfilteredRowIterator	applyToPartition(UnfilteredRowIterator iter) Applied to any rows iterator (partition) we encounter in a partitions iterator
static UnfilteredPartitionIterator	maybeWrap(UnfilteredPartitionIterator iterator, CFMetaData metadata, int nowInSec)
static UnfilteredRowIterator	maybeWrap(UnfilteredRowIterator iterator, int nowInSec)

Methods inherited from class org.apache.cassandra.db.transform.Transformation

apply, apply, apply, apply, applyToDeletion, applyToMarker, applyToPartitionKey, applyToRow, applyToStatic, onClose, onPartitionClose

Methods inherited from class java.lang.Object

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

Method Detail

maybeWrap

public static UnfilteredPartitionIterator maybeWrap(UnfilteredPartitionIterator iterator,
                                                    CFMetaData metadata,
                                                    int nowInSec)

maybeWrap

public static UnfilteredRowIterator maybeWrap(UnfilteredRowIterator iterator,
                                              int nowInSec)

applyToPartition

public UnfilteredRowIterator applyToPartition(UnfilteredRowIterator iter)

Description copied from class: Transformation

Applied to any rows iterator (partition) we encounter in a partitions iterator

Overrides:

applyToPartition in class Transformation<UnfilteredRowIterator>