Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

import java.util.function.Function;
import java.util.function.Predicate;

public class Main {
    public static <T> Predicate<T> distinctByKey(Function<? super T, ?> keyExtractor) {
        Map<Object, Boolean> seen = new ConcurrentHashMap<>();
        return t -> seen.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null;
    }
}