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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.helpers;
18  
19  import java.nio.charset.Charset;
20  
21  import org.apache.logging.log4j.status.StatusLogger;
22  
23  /**
24   * Charset utilities.
25   */
26  public final class Charsets {
27  
28      private static final String UTF_8 = "UTF-8";
29  
30      private Charsets() {
31      }
32  
33      /**
34       * Gets a Charset, starting with the preferred {@code charsetName} if supported, if not, use UTF-8.
35       *
36       * @param charsetName
37       *            the preferred charset name
38       * @return a Charset, not null.
39       */
40      public static Charset getSupportedCharset(final String charsetName) {
41          Charset charset = null;
42          if (charsetName != null) {
43              if (Charset.isSupported(charsetName)) {
44                  charset = Charset.forName(charsetName);
45              }
46          }
47          if (charset == null) {
48              charset = Charset.forName(UTF_8);
49              if (charsetName != null) {
50                  StatusLogger.getLogger().error("Charset " + charsetName + " is not supported for layout, using " +
51                      charset.displayName());
52              }
53          }
54          return charset;
55      }
56  
57  }