View Javadoc

    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements. See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache license, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License. You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the license for the specific language governing permissions and
    15   * limitations under the license.
    16   */
    17  package org.apache.logging.log4j.core.util;
    18
    19  /**
    20   * Utility class providing common validation logic.
    21   */
    22  public final class Assert {
    23      private Assert() {
    24      }
    25
    26      /**
    27       * Throws a {@code NullPointerException} if the specified parameter is
    28       * {@code null}, otherwise returns the specified parameter.
    29       * <p>
    30       * On Java 7, just use {@code Objects.requireNonNull(T, String)}
    31       * </p>
    32       * <p>
    33       * Usage:
    34       * </p>
    35       * <pre>
    36       * // earlier you would write this:
    37       * public SomeConstructor(Object param) {
    38       *     if (param == null) {
    39       *         throw new NullPointerException(&quot;param&quot;);
    40       *     }
    41       *     this.field = param;
    42       * }
    43       *
    44       * // now you can do the same in one line:
    45       * public SomeConstructor(Object param) {
    46       *     this.field = Assert.requireNonNull(&quot;param&quot;);
    47       * }
    48       * </pre>
    49       *
    50       * @param <T> the type of the parameter to check and return
    51       * @param object the parameter to check
    52       * @param message message to populate the NPE with if necessary
    53       * @return the specified parameter
    54       * @throws NullPointerException if {@code object} is {@code null}
    55       */
    56      public static <T> T requireNonNull(final T object, final String message) {
    57          if (object == null) {
    58              throw new NullPointerException(message);
    59          }
    60          return object;
    61      }
    62  }