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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.jmx;
18  
19  /**
20   * Utility class providing common validation logic.
21   */
22  public 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       * Usage:
31       * 
32       * <pre>
33       * // earlier you would write this:
34       * public SomeConstructor(Object param) {
35       *     if (param == null) {
36       *         throw new NullPointerException(name + &quot; is null&quot;);
37       *     }
38       *     this.field = param;
39       * }
40       * 
41       * // now you can do the same in one line:
42       * public SomeConstructor(Object param) {
43       *     this.field = Assert.isNotNull(param);
44       * }
45       * </pre>
46       * 
47       * @param checkMe the parameter to check
48       * @param name name of the parameter to use in the error message if
49       *            {@code null}
50       * @return the specified parameter
51       */
52      public static <T> T isNotNull(T checkMe, String name) {
53          if (checkMe == null) {
54              throw new NullPointerException(name + " is null");
55          }
56          return checkMe;
57      }
58  }