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.util;
018    
019    import java.security.MessageDigest;
020    
021    import org.apache.logging.log4j.util.Strings;
022    
023    /**
024     *
025     */
026    public final class NameUtil {
027    
028        private static final int MASK = 0xff;
029    
030        private NameUtil() {
031        }
032    
033        public static String getSubName(final String name) {
034            if (name.isEmpty()) {
035                return null;
036            }
037            final int i = name.lastIndexOf('.');
038            return i > 0 ? name.substring(0, i) : Strings.EMPTY;
039        }
040    
041        public static String md5(final String string) {
042            try {
043                final MessageDigest digest = MessageDigest.getInstance("MD5");
044                digest.update(string.getBytes());
045                final byte[] bytes = digest.digest();
046                final StringBuilder md5 = new StringBuilder();
047                for (final byte b : bytes) {
048                    final String hex = Integer.toHexString(MASK & b);
049                    if (hex.length() == 1) {
050                        md5.append('0');
051                    }
052                    md5.append(hex);
053                }
054                return md5.toString();
055            } catch (final Exception ex) {
056                return string;
057            }
058        }
059    }