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    }