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
019import java.util.regex.Pattern;
020
021/**
022 * Pattern strings used throughout Log4j.
023 * 
024 * @see Pattern
025 */
026public 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}