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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      /**
29       * UTF-8 Charset.
30       */
31      public static final Charset UTF_8 = Charset.forName("UTF-8");
32  
33      /**
34       * Returns a Charset, if possible the Charset for the specified {@code charsetName}, otherwise (if the specified
35       * {@code charsetName} is {@code null} or not supported) this method returns the platform default Charset.
36       *
37       * @param charsetName
38       *            name of the preferred charset or {@code null}
39       * @return a Charset, not null.
40       */
41      public static Charset getSupportedCharset(final String charsetName) {
42          return getSupportedCharset(charsetName, Charset.defaultCharset());
43      }
44  
45      /**
46       * Returns a Charset, if possible the Charset for the specified {@code charsetName}, otherwise (if the specified
47       * {@code charsetName} is {@code null} or not supported) this method returns the platform default Charset.
48       *
49       * @param charsetName
50       *            name of the preferred charset or {@code null}
51       * @param defaultCharset
52       *            returned if {@code charsetName} is null or is not supported.
53       * @return a Charset, never null.
54       */
55      public static Charset getSupportedCharset(final String charsetName, final Charset defaultCharset) {
56          Charset charset = null;
57          if (charsetName != null && Charset.isSupported(charsetName)) {
58              charset = Charset.forName(charsetName);
59          }
60          if (charset == null) {
61              charset = defaultCharset;
62              if (charsetName != null) {
63                  StatusLogger.getLogger().error(
64                          "Charset " + charsetName + " is not supported for layout, using " + charset.displayName());
65              }
66          }
67          return charset;
68      }
69  
70      private Charsets() {
71      }
72  
73  }