001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.util;
018
019/**
020 * Utility class providing common validation logic.
021 */
022public final class Assert {
023    private Assert() {
024    }
025
026    /**
027     * Throws a {@code NullPointerException} if the specified parameter is
028     * {@code null}, otherwise returns the specified parameter.
029     * <p>
030     * On Java 7, just use {@code Objects.requireNonNull(T, String)}
031     * </p>
032     * <p>
033     * Usage:
034     * </p>
035     * <pre>
036     * // earlier you would write this:
037     * public SomeConstructor(Object param) {
038     *     if (param == null) {
039     *         throw new NullPointerException(&quot;param&quot;);
040     *     }
041     *     this.field = param;
042     * }
043     *
044     * // now you can do the same in one line:
045     * public SomeConstructor(Object param) {
046     *     this.field = Assert.requireNonNull(&quot;param&quot;);
047     * }
048     * </pre>
049     *
050     * @param <T> the type of the parameter to check and return
051     * @param object the parameter to check
052     * @param message message to populate the NPE with if necessary
053     * @return the specified parameter
054     * @throws NullPointerException if {@code object} is {@code null}
055     */
056    public static <T> T requireNonNull(final T object, final String message) {
057        if (object == null) {
058            throw new NullPointerException(message);
059        }
060        return object;
061    }
062}