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.util.regex.Pattern;
020    
021    /**
022     * Pattern strings used throughout Log4j.
023     * 
024     * @see Pattern
025     */
026    public final class Patterns {
027    
028        /**
029         * A pattern string for comma separated lists with optional whitespace.
030         */
031        public static final String COMMA_SEPARATOR = toWhitespaceSeparator(",");
032    
033        /**
034         * The whitespace pattern string.
035         */
036        public static final String WHITESPACE = "\\s*";
037    
038        private Patterns() {
039        }
040    
041        /**
042         * Creates a pattern string for {@code separator} surrounded by whitespace.
043         * 
044         * @param separator The separator.
045         * @return a pattern for {@code separator} surrounded by whitespace.
046         */
047        public static String toWhitespaceSeparator(final String separator) {
048            return WHITESPACE + separator + WHITESPACE;
049        }
050    
051    }