Statistics (Apache Parquet Column 1.14.2 API)

java.lang.Object
- org.apache.parquet.column.statistics.Statistics<T>

Type Parameters:

T - the Java type described by this Statistics instance

Direct Known Subclasses:

BinaryStatistics, BooleanStatistics, DoubleStatistics, FloatStatistics, IntStatistics, LongStatistics
```
public abstract class Statistics<T extends Comparable<T>>
extends Object
```
Statistics class to keep track of statistics in parquet pages and column chunks

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class Statistics.Builder
Builder class to build Statistics objects.

Nested Classes
Modifier and Type	Class and Description
`static class`	`Statistics.Builder` Builder class to build Statistics objects.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`PrimitiveComparator<T>`	`comparator()` Returns the `PrimitiveComparator` implementation to be used to compare two generic values in the proper way (for example, unsigned comparison for UINT_32).
`int`	`compareMaxToValue(T value)` Compares max to the specified value in the proper way.
`int`	`compareMinToValue(T value)` Compares min to the specified value in the proper way.
`abstract Statistics<T>`	`copy()`
`static Statistics<?>`	`createStats(Type type)` Creates an empty `Statistics` instance for the specified type to be used for reading/writing the new min/max statistics used in the V2 format.
`boolean`	`equals(Object other)` Equality comparison method to compare two statistics objects.
`abstract T`	`genericGetMax()` Returns the max value in the statistics.
`abstract T`	`genericGetMin()` Returns the min value in the statistics.
`static Statistics.Builder`	`getBuilderForReading(PrimitiveType type)` Returns a builder to create new statistics object.
`abstract byte[]`	`getMaxBytes()` Abstract method to return the max value as a byte array
`abstract byte[]`	`getMinBytes()` Abstract method to return the min value as a byte array
`long`	`getNumNulls()` Returns the null count
`static Statistics`	`getStatsBasedOnType(PrimitiveType.PrimitiveTypeName type)` Deprecated. Use `createStats(Type)` instead
`int`	`hashCode()` Hash code for the statistics object
`boolean`	`hasNonNullValue()` Returns whether there have been non-null values added to this statistics
`void`	`incrementNumNulls()` Increments the null count by one
`void`	`incrementNumNulls(long increment)` Increments the null count by the parameter value
`boolean`	`isEmpty()` Returns a boolean specifying if the Statistics object is empty, i.e does not contain valid statistics for the page/column yet
`boolean`	`isNumNullsSet()`
`abstract boolean`	`isSmallerThan(long size)` Abstract method to return whether the min and max values fit in the given size.
`protected void`	`markAsNotEmpty()` Sets the page/column as having a valid non-null value kind of misnomer here
`String`	`maxAsString()` Returns the string representation of max for debugging/logging purposes.
`void`	`mergeStatistics(Statistics stats)` Method to merge this statistics object with the object passed as parameter.
`protected abstract void`	`mergeStatisticsMinMax(Statistics stats)` Abstract method to merge this statistics min and max with the values of the parameter object.
`String`	`minAsString()` Returns the string representation of min for debugging/logging purposes.
`abstract void`	`setMinMaxFromBytes(byte[] minBytes, byte[] maxBytes)` Deprecated. will be removed in 2.0.0. Use `getBuilderForReading(PrimitiveType)` instead.
`void`	`setNumNulls(long nulls)` Deprecated. will be removed in 2.0.0. Use `getBuilderForReading(PrimitiveType)` instead.
`String`	`toString()`
`PrimitiveType`	`type()`
`void`	`updateStats(Binary value)` updates statistics min and max using the passed value
`void`	`updateStats(boolean value)` updates statistics min and max using the passed value
`void`	`updateStats(double value)` updates statistics min and max using the passed value
`void`	`updateStats(float value)` updates statistics min and max using the passed value
`void`	`updateStats(int value)` updates statistics min and max using the passed value
`void`	`updateStats(long value)` updates statistics min and max using the passed value

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Method Detail
  - getStatsBasedOnType
```
@Deprecated
public static Statistics getStatsBasedOnType(PrimitiveType.PrimitiveTypeName type)
```
    Deprecated. Use createStats(Type) instead
    
    Returns the typed statistics object based on the passed type parameter
    
    Parameters:
    
    type - PrimitiveTypeName type of the column
    
    Returns:
    
    instance of a typed statistics class
  - createStats
```
public static Statistics<?> createStats(Type type)
```
    Creates an empty Statistics instance for the specified type to be used for reading/writing the new min/max statistics used in the V2 format.
    
    Parameters:
    
    type - type of the column
    
    Returns:
    
    instance of a typed statistics class
  - getBuilderForReading
```
public static Statistics.Builder getBuilderForReading(PrimitiveType type)
```
    Returns a builder to create new statistics object. Used to read the statistics from the parquet file.
    
    Parameters:
    
    type - type of the column
    
    Returns:
    
    builder to create new statistics object
  - updateStats
```
public void updateStats(int value)
```
    updates statistics min and max using the passed value
    
    Parameters:
    
    value - value to use to update min and max
  - updateStats
```
public void updateStats(long value)
```
    updates statistics min and max using the passed value
    
    Parameters:
    
    value - value to use to update min and max
  - updateStats
```
public void updateStats(float value)
```
    updates statistics min and max using the passed value
    
    Parameters:
    
    value - value to use to update min and max
  - updateStats
```
public void updateStats(double value)
```
    updates statistics min and max using the passed value
    
    Parameters:
    
    value - value to use to update min and max
  - updateStats
```
public void updateStats(boolean value)
```
    updates statistics min and max using the passed value
    
    Parameters:
    
    value - value to use to update min and max
  - updateStats
```
public void updateStats(Binary value)
```
    updates statistics min and max using the passed value
    
    Parameters:
    
    value - value to use to update min and max
  - equals
```
public boolean equals(Object other)
```
    Equality comparison method to compare two statistics objects.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    other - Object to compare against
    
    Returns:
    
    true if objects are equal, false otherwise
  - hashCode
```
public int hashCode()
```
    Hash code for the statistics object
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    hash code int
  - mergeStatistics
```
public void mergeStatistics(Statistics stats)
```
    Method to merge this statistics object with the object passed as parameter. Merging keeps the smallest of min values, largest of max values and combines the number of null counts.
    
    Parameters:
    
    stats - Statistics object to merge with
  - mergeStatisticsMinMax
```
protected abstract void mergeStatisticsMinMax(Statistics stats)
```
    Abstract method to merge this statistics min and max with the values of the parameter object. Does not do any checks, only called internally.
    
    Parameters:
    
    stats - Statistics object to merge with
  - setMinMaxFromBytes
```
@Deprecated
public abstract void setMinMaxFromBytes(byte[] minBytes,
                                                    byte[] maxBytes)
```
    Deprecated. will be removed in 2.0.0. Use getBuilderForReading(PrimitiveType) instead.
    
    Abstract method to set min and max values from byte arrays.
    
    Parameters:
    
    minBytes - byte array to set the min value to
    
    maxBytes - byte array to set the max value to
  - genericGetMin
```
public abstract T genericGetMin()
```
    Returns the min value in the statistics. The java natural order of the returned type defined by Comparable.compareTo(Object) might not be the proper one. For example, UINT_32 requires unsigned comparison instead of the natural signed one. Use compareMinToValue(Comparable) or the comparator returned by comparator() to always get the proper ordering.
    
    Returns:
    
    the min value
  - genericGetMax
```
public abstract T genericGetMax()
```
    Returns the max value in the statistics. The java natural order of the returned type defined by Comparable.compareTo(Object) might not be the proper one. For example, UINT_32 requires unsigned comparison instead of the natural signed one. Use compareMaxToValue(Comparable) or the comparator returned by comparator() to always get the proper ordering.
    
    Returns:
    
    the max value
  - comparator
```
public final PrimitiveComparator<T> comparator()
```
    Returns the PrimitiveComparator implementation to be used to compare two generic values in the proper way (for example, unsigned comparison for UINT_32).
    
    Returns:
    
    the comparator for data described by this Statistics instance
  - compareMinToValue
```
public final int compareMinToValue(T value)
```
    Compares min to the specified value in the proper way. It does the same as invoking comparator().compare(genericGetMin(), value). The corresponding statistics implementations overload this method so the one with the primitive argument shall be used to avoid boxing/unboxing.
    
    Parameters:
    
    value - the value which min is to be compared to
    
    Returns:
    
    a negative integer, zero, or a positive integer as min is less than, equal to, or greater than value.
  - compareMaxToValue
```
public final int compareMaxToValue(T value)
```
    Compares max to the specified value in the proper way. It does the same as invoking comparator().compare(genericGetMax(), value). The corresponding statistics implementations overload this method so the one with the primitive argument shall be used to avoid boxing/unboxing.
    
    Parameters:
    
    value - the value which max is to be compared to
    
    Returns:
    
    a negative integer, zero, or a positive integer as max is less than, equal to, or greater than value.
  - getMaxBytes
```
public abstract byte[] getMaxBytes()
```
    Abstract method to return the max value as a byte array
    
    Returns:
    
    byte array corresponding to the max value
  - getMinBytes
```
public abstract byte[] getMinBytes()
```
    Abstract method to return the min value as a byte array
    
    Returns:
    
    byte array corresponding to the min value
  - minAsString
```
public String minAsString()
```
    Returns the string representation of min for debugging/logging purposes.
    
    Returns:
    
    the min value as a string
  - maxAsString
```
public String maxAsString()
```
    Returns the string representation of max for debugging/logging purposes.
    
    Returns:
    
    the max value as a string
  - isSmallerThan
```
public abstract boolean isSmallerThan(long size)
```
    Abstract method to return whether the min and max values fit in the given size.
    
    Parameters:
    
    size - a size in bytes
    
    Returns:
    
    true iff the min and max values are less than size bytes
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - incrementNumNulls
```
public void incrementNumNulls()
```
    Increments the null count by one
  - incrementNumNulls
```
public void incrementNumNulls(long increment)
```
    Increments the null count by the parameter value
    
    Parameters:
    
    increment - value to increment the null count by
  - getNumNulls
```
public long getNumNulls()
```
    Returns the null count
    
    Returns:
    
    null count or -1 if the null count is not set
  - setNumNulls
```
@Deprecated
public void setNumNulls(long nulls)
```
    Deprecated. will be removed in 2.0.0. Use getBuilderForReading(PrimitiveType) instead.
    
    Sets the number of nulls to the parameter value
    
    Parameters:
    
    nulls - null count to set the count to
  - isEmpty
```
public boolean isEmpty()
```
    Returns a boolean specifying if the Statistics object is empty, i.e does not contain valid statistics for the page/column yet
    
    Returns:
    
    true if object is empty, false otherwise
  - hasNonNullValue
```
public boolean hasNonNullValue()
```
    Returns whether there have been non-null values added to this statistics
    
    Returns:
    
    true if the values contained at least one non-null value
  - isNumNullsSet
```
public boolean isNumNullsSet()
```
    Returns:
    
    whether numNulls is set and can be used
  - markAsNotEmpty
```
protected void markAsNotEmpty()
```
    Sets the page/column as having a valid non-null value kind of misnomer here
  - copy
```
public abstract Statistics<T> copy()
```
    Returns:
    
    a new independent statistics instance of this class.
  - type
```
public PrimitiveType type()
```
    Returns:
    
    the primitive type object which this statistics is created for

Class Statistics<T extends Comparable<T>>

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

getStatsBasedOnType

createStats

getBuilderForReading

updateStats

updateStats

updateStats

updateStats

updateStats

updateStats

equals

hashCode

mergeStatistics

mergeStatisticsMinMax

setMinMaxFromBytes

genericGetMin

genericGetMax

comparator

compareMinToValue

compareMaxToValue

getMaxBytes

getMinBytes

minAsString

maxAsString

isSmallerThan

toString

incrementNumNulls

incrementNumNulls

getNumNulls

setNumNulls

isEmpty

hasNonNullValue

isNumNullsSet

markAsNotEmpty

copy

type