Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
//License from project: BSD License 

import java.util.ArrayList;

import java.util.Collection;

import java.util.Map;

public class Main {
    /**
     * Returns the collection value for the given key, creating and associating
     * a new, empty {@link ArrayList} if the key's value is null.
     * 
     * @param <K>
     *            The map's key type.
     * @param <V>
     *            The map's collection value type.
     * @param collectionMap
     *            The map to evaluate.
     * @param key
     *            The key to fetch.
     * @return A collection of values for the given key.
     */
    public static <K, V> Collection<V> initCollectionValue(final Map<K, Collection<V>> collectionMap, final K key) {
        Collection<V> collection = collectionMap.get(key);
        if (collection == null) {
            collection = new ArrayList<V>();
            collectionMap.put(key, collection);
        }
        return collection;
    }
}