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     */
017    package org.apache.logging.log4j.core.helpers;
018    
019    import java.nio.charset.Charset;
020    
021    import org.apache.logging.log4j.status.StatusLogger;
022    
023    /**
024     * Charset utilities.
025     */
026    public final class Charsets {
027    
028        private Charsets() {
029        }
030    
031        /**
032         * Gets a Charset, starting with the preferred {@code charsetName} if supported, if not, use UTF-8, if not
033         * supported, use the platform default.
034         *
035         * @param charsetName
036         *            the preferred charset name
037         * @return a Charset, not null.
038         */
039        public static Charset getSupportedCharset(final String charsetName) {
040            Charset charset = null;
041            if (charsetName != null) {
042                if (Charset.isSupported(charsetName)) {
043                    charset = Charset.forName(charsetName);
044                }
045            }
046            if (charset == null) {
047                charset = Charset.isSupported("UTF-8") ? Charset.forName("UTF-8") : Charset.defaultCharset();
048                if (charsetName != null) {
049                    StatusLogger.getLogger().error("Charset " + charsetName + " is not supported for layout, using " +
050                        charset.displayName());
051                }
052            }
053            return charset;
054        }
055    
056    }