org.apache.drill.metastore.statistics

Class ColumnStatistics<T>

java.lang.Object

org.apache.drill.metastore.statistics.ColumnStatistics<T>

Type Parameters:

T - type of column values

public class ColumnStatistics<T>
extends Object

Represents collection of statistics values for specific column. For example, text representation of ColumnStatistics for varchar column is the following:

 {
     "statistics":[
         {"statisticsValue":2.1,"statisticsKind":{"name":"approx_count_distinct"}},
         {"statisticsValue":"aaa","statisticsKind":{"exact":true,"name":"minValue"}},
         {"statisticsValue":3,"statisticsKind":{"exact":true,"name":"nullsCount"}},
         {"statisticsValue":"zzz","statisticsKind":{"exact":true,"name":"maxValue"}}],
     "type":"VARCHAR"
 }
 

Constructor Summary

Constructors

Constructor and Description
ColumnStatistics(Collection<StatisticsHolder<?>> statistics)
ColumnStatistics(Collection<StatisticsHolder<?>> statistics, TypeProtos.MinorType type)

Method Summary

Modifier and Type	Method and Description
ColumnStatistics<T>	cloneWith(ColumnStatistics<T> sourceStatistics) Returns new ColumnStatistics instance with overridden statistics taken from specified ColumnStatistics.
boolean	contains(StatisticsKind<?> statisticsKind) Checks whether specified statistics kind is set in this column statistics.
boolean	containsExact(StatisticsKind<?> statisticsKind) Checks whether specified statistics kind is set in this column statistics and it corresponds to the exact statistics value.
boolean	equals(Object o)
ColumnStatistics<T>	genericClone(ColumnStatistics<?> sourceStatistics)
<V> V	get(StatisticsKind<V> statisticsKind) Returns statistics value which corresponds to specified StatisticsKind.
TypeProtos.MinorType	getComparatorType()
Comparator<T>	getValueComparator() Returns Comparator for comparing values with the same type as column values.
int	hashCode()
String	jsonString()
static ColumnStatistics<?>	of(String columnStatistics)
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ColumnStatistics

public ColumnStatistics(Collection<StatisticsHolder<?>> statistics,
                        TypeProtos.MinorType type)

ColumnStatistics

public ColumnStatistics(Collection<StatisticsHolder<?>> statistics)

Method Detail

get

public <V> V get(StatisticsKind<V> statisticsKind)

Returns statistics value which corresponds to specified StatisticsKind.

Parameters:

statisticsKind - kind of statistics which value should be returned

Returns:

statistics value

contains

public boolean contains(StatisticsKind<?> statisticsKind)

Checks whether specified statistics kind is set in this column statistics.

Parameters:

statisticsKind - statistics kind to check

Returns:

true if specified statistics kind is set

containsExact

public boolean containsExact(StatisticsKind<?> statisticsKind)

Checks whether specified statistics kind is set in this column statistics and it corresponds to the exact statistics value.

Parameters:

statisticsKind - statistics kind to check

Returns:

true if value which corresponds to the specified statistics kind is exact

getValueComparator

public Comparator<T> getValueComparator()

Returns Comparator for comparing values with the same type as column values.

Returns:

Comparator

cloneWith

public ColumnStatistics<T> cloneWith(ColumnStatistics<T> sourceStatistics)

Returns new ColumnStatistics instance with overridden statistics taken from specified ColumnStatistics.

Parameters:

sourceStatistics - source of statistics to override

Returns:

new ColumnStatistics instance with overridden statistics

genericClone

public ColumnStatistics<T> genericClone(ColumnStatistics<?> sourceStatistics)

getComparatorType

public TypeProtos.MinorType getComparatorType()

jsonString

public String jsonString()

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

of

public static ColumnStatistics<?> of(String columnStatistics)