Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
//License from project: Open Source License 

import java.util.Collection;

import java.util.Map;

import java.util.function.BinaryOperator;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Main {
    @SafeVarargs
    public static <K, V> Map<K, V> preservedUnionMap(Map<K, V>... maps) {
        return unionMap(true, maps);
    }

    @SafeVarargs
    public static <K, V> Map<K, V> unionMap(Map<K, V>... maps) {
        return unionMap(false, maps);
    }

    @SafeVarargs
    public static <K, V> Map<K, V> unionMap(boolean preserved, Map<K, V>... maps) {
        return Stream.of(maps).map(Map::entrySet).flatMap(Collection::stream).collect(Collectors
                .toMap(Map.Entry::getKey, Map.Entry::getValue, preserved ? preserveMerger() : abandonMerger()));
    }

    public static <T> BinaryOperator<T> preserveMerger() {
        return mergeDuplicates(false);
    }

    public static <T> BinaryOperator<T> abandonMerger() {
        return mergeDuplicates(true);
    }

    public static <T> BinaryOperator<T> mergeDuplicates(boolean override) {
        return (u, v) -> override ? v : u;
    }
}