src/main/java/org/zwobble/couscous/util/ExtraArrays.java


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package org.zwobble.couscous.util;

import java.util.Arrays;
import java.util.Optional;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.stream.IntStream;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;

public class ExtraArrays {
    public static <T, R> Stream<R> mapWithIndex(T[] array, BiFunction<Integer, T, R> function) {
        return IntStream.range(0, array.length)
            .mapToObj(index -> function.apply(index,  array[index]));
    }
    
    public static <T, R> Stream<R> map(T[] array, Function<T, R> function) {
        return stream(array).map(function);
    }
    
    public static <T> Stream<T> stream(T[] array) {
        return StreamSupport.stream(Arrays.spliterator(array), false);
    }

    public static <T> Optional<T> last(T[] array) {
        if (array.length == 0) {
            return Optional.empty();
        } else {
            return Optional.of(array[array.length - 1]);
        }
    }
}