Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
import java.util.*;
import java.util.function.Function;

public class Main {
    public static <T, U> List<U> mapViaFoldLeft(List<T> list, Function<T, U> f) {
        return foldLeft(list, list(), x -> y -> append(x, f.apply(y)));
    }

    public static <T, U> U foldLeft(List<T> ts, U identity, Function<U, Function<T, U>> f) {
        U result = identity;
        for (T t : ts) {
            result = f.apply(result).apply(t);
        }
        return result;
    }

    public static <T> List<T> list() {
        return Collections.emptyList();
    }

    public static <T> List<T> list(T t) {
        return Collections.singletonList(t);
    }

    public static <T> List<T> list(List<T> ts) {
        return Collections.unmodifiableList(new ArrayList<>(ts));
    }

    @SafeVarargs
    public static <T> List<T> list(T... t) {
        return Collections.unmodifiableList(Arrays.asList(Arrays.copyOf(t, t.length)));
    }

    public static <T> List<T> append(List<T> list, T t) {
        List<T> ts = copy(list);
        ts.add(t);
        return Collections.unmodifiableList(ts);
    }

    private static <T> List<T> copy(List<T> ts) {
        return new ArrayList<>(ts);
    }
}