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 */
017package org.apache.logging.log4j.core.util;
018
019/**
020 * Pattern strings used throughout Log4j.
021 *
022 * @see java.util.regex.Pattern
023 */
024public final class Patterns {
025
026    /**
027     * A pattern string for comma separated lists with optional whitespace.
028     */
029    public static final String COMMA_SEPARATOR = toWhitespaceSeparator(",");
030
031    /**
032     * The whitespace pattern string.
033     */
034    public static final String WHITESPACE = "\\s*";
035
036    private Patterns() {
037    }
038
039    /**
040     * Creates a pattern string for {@code separator} surrounded by whitespace.
041     *
042     * @param separator The separator.
043     * @return a pattern for {@code separator} surrounded by whitespace.
044     */
045    public static String toWhitespaceSeparator(final String separator) {
046        return WHITESPACE + separator + WHITESPACE;
047    }
048}