Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright Terracotta, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.HashMap;
import java.util.Map;

public class Main {
    /**
     * Copy each map entry to a new map but check that each key and value isn't null. Throw
     * a {@code NullPointerException} if it's the case.
     *
     * @param entries entries to copy
     * @param <K> type of key
     * @param <V> type of value
     * @return cloned map
     * @throws NullPointerException if a key or value is null
     */
    public static <K, V> Map<K, V> copyMapButFailOnNull(Map<? extends K, ? extends V> entries) {
        Map<K, V> entriesToRemap = new HashMap<>(entries.size());
        entries.forEach((k, v) -> {
            // If a key/value is null, throw NPE, nothing gets mutated
            if (k == null || v == null) {
                throw new NullPointerException();
            }
            entriesToRemap.put(k, v);
        });
        return entriesToRemap;
    }
}