uk.ac.starlink.util

Class StreamUtil

java.lang.Object

uk.ac.starlink.util.StreamUtil

public class StreamUtil
extends Object

Utilities for use with java Streams.

Since:

23 Jun 2023

Author:

Mark Taylor

Method Summary

Modifier and Type	Method and Description
static <T,R> java.util.function.Function<T,java.util.stream.Stream<R>>	keepInstances(Class<R> keepClazz) Utility function that can be used to filter streams to exclude any elements that are not instances of a particular type.

Methods inherited from class java.lang.Object

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

Method Detail

keepInstances

public static <T,R> java.util.function.Function<T,java.util.stream.Stream<R>> keepInstances(Class<R> keepClazz)

Utility function that can be used to filter streams to exclude any elements that are not instances of a particular type. This doesn't do anything particularly complicated, but it allows one to combine a filter (for class) step with a type-casting step in a way which is commonly required and otherwise annoyingly verbose.

Use the result of this method as the argument to Stream.flatMap(java.util.function.Function<? super T, ? extends java.util.stream.Stream<? extends R>>).

Parameters:

keepClazz - class for which instances are required

Returns:

function for use in flatMap