Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import java.util.Collection;

import java.util.Map;

public class Main {
    /**
     * Add {@code value} to collection {@code map}.get({@code key}). If {@code key} does not exists
     * yet, set it to {@code emptyCollection} before addition.
     */
    public static <K, V extends Collection<E>, E> void upsert(Map<K, V> map, K key, E value, V emptyCollection) {
        V collection = map.get(key);
        if (collection == null) {
            collection = emptyCollection;
        }
        collection.add(value);
        map.put(key, collection);
    }
}