Package io.substrait.relation

Class CopyOnWriteUtils

java.lang.Object

io.substrait.relation.CopyOnWriteUtils

public class CopyOnWriteUtils
extends Object

Provides common utilities for copy-on-write visitations

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	CopyOnWriteUtils.TransformFunction<T,C extends VisitationContext,E extends Exception>

Constructor Summary

Constructors

Constructor	Description
CopyOnWriteUtils()

Method Summary

Modifier and Type	Method	Description
static boolean	allEmpty(Optional<?>... optionals)
static <T> Optional<T>	or(Optional<T> left, Supplier<? extends Optional<T>> right)	The `or` method on Optional instances is a Java 9+ feature
static <I, C extends VisitationContext, E extends Exception> Optional<List<I>>	transformList(List<I> items, C context, CopyOnWriteUtils.TransformFunction<I,C,E> transform)	Applies the given transformation function to each item in the list.

Methods inherited from class java.lang.Object

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

Constructor Details

CopyOnWriteUtils

public CopyOnWriteUtils()

Method Details

allEmpty

public static boolean allEmpty(Optional<?>... optionals)

or

public static <T> Optional<T> or(Optional<T> left,
 Supplier<? extends Optional<T>> right)

The `or` method on Optional instances is a Java 9+ feature

transformList

public static <I,
C extends VisitationContext,
E extends Exception>
Optional<List<I>> transformList(List<I> items,
 C context,
 CopyOnWriteUtils.TransformFunction<I,C,E> transform)
                         throws E

Applies the given transformation function to each item in the list. If any of the list items are transformed, returns a new list in which each item is either

• a transformed new item replacing an old item
• the original item in the position it was in

Parameters:

items - the list of items to transform

transform - the transformation function to apply to each item

Returns:

An empty optional if none of the items have changed. An optional containing a new list otherwise.

Throws:

E extends Exception