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.pattern;
018
019import java.util.regex.Pattern;
020
021import org.apache.logging.log4j.Logger;
022import org.apache.logging.log4j.core.config.plugins.Plugin;
023import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
024import org.apache.logging.log4j.core.config.plugins.PluginFactory;
025import org.apache.logging.log4j.status.StatusLogger;
026
027/**
028 * Replace tokens in the LogEvent message.
029 */
030@Plugin(name = "replace", category = "Core", printObject = true)
031public 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 String 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        final Pattern p = Pattern.compile(regex);
082        return new RegexReplacement(p, replacement);
083    }
084
085}