    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.pattern;
    018
    019    import java.util.regex.Pattern;
    020
    021    import org.apache.logging.log4j.Logger;
    022    import org.apache.logging.log4j.core.config.plugins.Plugin;
    023    import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
    024    import org.apache.logging.log4j.core.config.plugins.PluginFactory;
    025    import org.apache.logging.log4j.status.StatusLogger;
    026
    027    /**
    028     * Replace tokens in the LogEvent message.
    029     */
    030    @Plugin(name = "replace", category = "Core", printObject = true)
    031    public final class RegexReplacement {
    032
    033        private static final Logger LOGGER = StatusLogger.getLogger();
    034
    035        private final Pattern pattern;
    036
    037        private final String substitution;
    038
    039        /**
    040         * Private constructor.
    041         *
    042         * @param pattern The Pattern.
    043         * @param substitution The substitution String.
    044         */
    045        private RegexReplacement(final Pattern pattern, final String substitution) {
    046            this.pattern = pattern;
    047            this.substitution = substitution;
    048        }
    049
    050        /**
    051         * Perform the replacement.
    052         * @param msg The String to match against.
    053         * @return the replacement String.
    054         */
    055        public String format(final String msg) {
    056            return pattern.matcher(msg).replaceAll(substitution);
    057        }
    058
    059        @Override
    060        public String toString() {
    061            return "replace(regex=" + pattern.pattern() + ", replacement=" + substitution + ')';
    062        }
    063
    064        /**
    065         * Create a RegexReplacement.
    066         * @param regex The regular expression to locate.
    067         * @param replacement The replacement value.
    068         * @return A RegexReplacement.
    069         */
    070        @PluginFactory
    071        public static RegexReplacement createRegexReplacement(
    072                @PluginAttribute("regex") final Pattern regex,
    073                @PluginAttribute("replacement") final String replacement) {
    074            if (regex == null) {
    075                LOGGER.error("A regular expression is required for replacement");
    076                return null;
    077            }
    078            if (replacement == null) {
    079                LOGGER.error("A replacement string is required to perform replacement");
    080            }
    081            // FIXME: should we use Matcher.quoteReplacement() here?
    082            return new RegexReplacement(regex, replacement);
    083        }
    084
    085    }