iceberg::Transform Class Reference

Represents a transform used in partitioning or sorting in Iceberg. More...

#include <transform.h>

Inheritance diagram for iceberg::Transform:

Public Member Functions
TransformType	transform_type () const
	Returns the transform type.
Result< std::shared_ptr< TransformFunction > >	Bind (const std::shared_ptr< Type > &source_type) const
	Binds this transform to a source type, returning a typed TransformFunction.
bool	CanTransform (const Type &source_type) const
	Checks whether this function can be applied to the given Type.
bool	PreservesOrder () const
	Whether the transform preserves the order of values (is monotonic).
bool	SatisfiesOrderOf (const Transform &other) const
	Whether ordering by this transform's result satisfies the ordering of another transform's result.
Result< std::unique_ptr< UnboundPredicate > >	Project (std::string_view name, const std::shared_ptr< BoundPredicate > &predicate)
	Transforms a BoundPredicate to an inclusive predicate on the partition values produced by the transform.
Result< std::unique_ptr< UnboundPredicate > >	ProjectStrict (std::string_view name, const std::shared_ptr< BoundPredicate > &predicate)
	Transforms a BoundPredicate to a strict predicate on the partition values produced by the transform.
Result< std::string >	ToHumanString (const Literal &value)
	Returns a human-readable string representation of a transformed value.
std::string	ToString () const override
	Returns a string representation of this transform (e.g., "bucket[16]").
std::string	DedupName () const
	Return the unique transform name to check if similar transforms for the same source field are added multiple times in partition spec builder.
Result< std::string >	GeneratePartitionName (std::string_view source_name) const
	Generates a partition name for the transform.

Static Public Member Functions
static std::shared_ptr< Transform >	Identity ()
	Returns a shared singleton instance of the Identity transform.
static std::shared_ptr< Transform >	Bucket (int32_t num_buckets)
	Creates a shared instance of the Bucket transform.
static std::shared_ptr< Transform >	Truncate (int32_t width)
	Creates a shared instance of the Truncate transform.
static std::shared_ptr< Transform >	Year ()
	Creates a shared singleton instance of the Year transform.
static std::shared_ptr< Transform >	Month ()
	Creates a shared singleton instance of the Month transform.
static std::shared_ptr< Transform >	Day ()
	Creates a shared singleton instance of the Day transform.
static std::shared_ptr< Transform >	Hour ()
	Creates a shared singleton instance of the Hour transform.
static std::shared_ptr< Transform >	Void ()
	Creates a shared singleton instance of the Void transform.

Friends
bool	operator== (const Transform &lhs, const Transform &rhs)
	Equality comparison.

Detailed Description

Represents a transform used in partitioning or sorting in Iceberg.

This class supports binding to a source type and instantiating the corresponding TransformFunction, as well as serialization-friendly introspection.

Member Function Documentation

Bind()

Result< std::shared_ptr< TransformFunction > > iceberg::Transform::Bind

(

const std::shared_ptr< Type > &

source_type

)

const

Binds this transform to a source type, returning a typed TransformFunction.

This creates a concrete transform implementation based on the transform type and parameter.

Parameters

source_type

The source column type to bind to.

Returns

A TransformFunction instance wrapped in expected, or an error on failure.

Bucket()

std::shared_ptr< Transform > iceberg::Transform::Bucket ( int32_t  num_buckets )

static

Creates a shared instance of the Bucket transform.

Buckets values using a hash modulo operation. Commonly used for distributing data.

Parameters

num_buckets

The number of buckets.

Returns

A shared pointer to the Bucket transform.

CanTransform()

bool iceberg::Transform::CanTransform

(

const Type &

source_type

)

const

Checks whether this function can be applied to the given Type.

Parameters

source_type

The source type to check.

Returns

true if this transform can be applied to the type, false otherwise

Day()

std::shared_ptr< Transform > iceberg::Transform::Day ( )

static

Creates a shared singleton instance of the Day transform.

Extracts the number of days from a date or timestamp since the epoch.

Returns

A shared pointer to the Day transform.

GeneratePartitionName()

Result< std::string > iceberg::Transform::GeneratePartitionName

(

std::string_view

source_name

)

const

Generates a partition name for the transform.

Parameters

source_name

The name of the source column.

Returns

A string representation of the partition name.

Hour()

std::shared_ptr< Transform > iceberg::Transform::Hour ( )

static

Creates a shared singleton instance of the Hour transform.

Extracts the number of hours from a timestamp since the epoch.

Returns

A shared pointer to the Hour transform.

Identity()

std::shared_ptr< Transform > iceberg::Transform::Identity ( )

static

Returns a shared singleton instance of the Identity transform.

This transform leaves values unchanged and is commonly used for direct partitioning.

Returns

A shared pointer to the Identity transform.

Month()

std::shared_ptr< Transform > iceberg::Transform::Month ( )

static

Creates a shared singleton instance of the Month transform.

Extracts the number of months from a date or timestamp since the epoch.

Returns

A shared pointer to the Month transform.

Project()

Result< std::unique_ptr< UnboundPredicate > > iceberg::Transform::Project	(	std::string_view	name,
		const std::shared_ptr< BoundPredicate > &	predicate
	)

Transforms a BoundPredicate to an inclusive predicate on the partition values produced by the transform.

This inclusive transform guarantees that if predicate->Test(value) is true, then Projected(transform(value)) is true.

Parameters

name	The name of the partition column.
predicate	The predicate to project.

Returns

A Result containing either a unique pointer to the projected predicate, nullptr if the projection cannot be performed, or an Error if the projection fails.

ProjectStrict()

Result< std::unique_ptr< UnboundPredicate > > iceberg::Transform::ProjectStrict	(	std::string_view	name,
		const std::shared_ptr< BoundPredicate > &	predicate
	)

Transforms a BoundPredicate to a strict predicate on the partition values produced by the transform.

This strict transform guarantees that if Projected(transform(value)) is true, then predicate->Test(value) is also true.

Parameters

name	The name of the partition column.
predicate	The predicate to project.

Returns

A Result containing either a unique pointer to the projected predicate, nullptr if the projection cannot be performed, or an Error if the projection fails.

SatisfiesOrderOf()

bool iceberg::Transform::SatisfiesOrderOf

(

const Transform &

other

)

const

Whether ordering by this transform's result satisfies the ordering of another transform's result.

For example, sorting by day(ts) will produce an ordering that is also by month(ts) or year(ts). However, sorting by day(ts) will not satisfy the order of hour(ts) or identity(ts).

Parameters

other

The other transform to compare with.

Returns

true if ordering by this transform is equivalent to ordering by the other transform.

ToHumanString()

Result< std::string > iceberg::Transform::ToHumanString

(

const Literal &

value

)

Returns a human-readable string representation of a transformed value.

Parameters

value

The literal value to be transformed.

Returns

A human-readable string representation of the value

ToString()

std::string iceberg::Transform::ToString ( ) const

overridevirtual

Returns a string representation of this transform (e.g., "bucket[16]").

Implements iceberg::util::Formattable.

Truncate()

std::shared_ptr< Transform > iceberg::Transform::Truncate ( int32_t  width )

static

Creates a shared instance of the Truncate transform.

Truncates values to a fixed width (e.g., for strings or binary data).

Parameters

width

The width to truncate to.

Returns

A shared pointer to the Truncate transform.

Void()

std::shared_ptr< Transform > iceberg::Transform::Void ( )

static

Creates a shared singleton instance of the Void transform.

Ignores values and always returns null. Useful for testing or special cases.

Returns

A shared pointer to the Void transform.

Year()

std::shared_ptr< Transform > iceberg::Transform::Year ( )

static

Creates a shared singleton instance of the Year transform.

Extracts the number of years from a date or timestamp since the epoch.

Returns

A shared pointer to the Year transform.

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The documentation for this class was generated from the following files:

• iceberg/transform.h
• iceberg/transform.cc