    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    }