org.apache.iceberg.transforms

Class Transforms

java.lang.Object

org.apache.iceberg.transforms.Transforms

public class Transforms
extends java.lang.Object

Factory methods for transforms.

Most users should create transforms using a PartitionSpec.builderFor(Schema) partition spec builder}.

See Also:

The partition spec builder.

Method Summary

Modifier and Type	Method and Description
static <T> Transform<T,java.lang.Void>	alwaysNull() Returns a Transform that always produces null.
static <T> Transform<T,java.lang.Integer>	bucket(Type type, int numBuckets) Returns a bucket Transform for the given type and number of buckets.
static <T> Transform<T,java.lang.Integer>	day(Type type) Returns a day Transform for date or timestamp types.
static Transform<?,?>	fromString(Type type, java.lang.String transform)
static <T> Transform<T,java.lang.Integer>	hour(Type type) Returns a hour Transform for timestamps.
static <T> Transform<T,T>	identity(Type type) Returns an identity Transform that can be used for any type.
static <T> Transform<T,java.lang.Integer>	month(Type type) Returns a month Transform for date or timestamp types.
static <T> Transform<T,T>	truncate(Type type, int width) Returns a truncate Transform for the given type and width.
static <T> Transform<T,java.lang.Integer>	year(Type type) Returns a year Transform for date or timestamp types.

Methods inherited from class java.lang.Object

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

Method Detail

fromString

public static Transform<?,?> fromString(Type type,
                                        java.lang.String transform)

identity

public static <T> Transform<T,T> identity(Type type)

Returns an identity Transform that can be used for any type.

Type Parameters:

T - Java type passed to this transform

Parameters:

type - the source type for the transform

Returns:

an identity transform

year

public static <T> Transform<T,java.lang.Integer> year(Type type)

Returns a year Transform for date or timestamp types.

Type Parameters:

T - Java type passed to this transform

Parameters:

type - the source type for the transform

Returns:

a year transform

month

public static <T> Transform<T,java.lang.Integer> month(Type type)

Returns a month Transform for date or timestamp types.

Type Parameters:

T - Java type passed to this transform

Parameters:

type - the source type for the transform

Returns:

a month transform

day

public static <T> Transform<T,java.lang.Integer> day(Type type)

Returns a day Transform for date or timestamp types.

Type Parameters:

T - Java type passed to this transform

Parameters:

type - the source type for the transform

Returns:

a day transform

hour

public static <T> Transform<T,java.lang.Integer> hour(Type type)

Returns a hour Transform for timestamps.

Type Parameters:

T - Java type passed to this transform

Parameters:

type - the source type for the transform

Returns:

a hour transform

bucket

public static <T> Transform<T,java.lang.Integer> bucket(Type type,
                                                        int numBuckets)

Returns a bucket Transform for the given type and number of buckets.

Type Parameters:

T - Java type passed to this transform

Parameters:

type - the source type for the transform

numBuckets - the number of buckets for the transform to produce

Returns:

a transform that buckets values into numBuckets

truncate

public static <T> Transform<T,T> truncate(Type type,
                                          int width)

Returns a truncate Transform for the given type and width.

Type Parameters:

T - Java type passed to this transform

Parameters:

type - the source type for the transform

width - the width to truncate data values

Returns:

a transform that truncates the given type to width

alwaysNull

public static <T> Transform<T,java.lang.Void> alwaysNull()

Returns a Transform that always produces null.

Type Parameters:

T - Java type accepted by the transform.

Returns:

a transform that always produces null (the void transform).