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.lookup;
018
019import java.text.DateFormat;
020import java.text.SimpleDateFormat;
021import java.util.Date;
022
023import org.apache.logging.log4j.Logger;
024import org.apache.logging.log4j.core.LogEvent;
025import org.apache.logging.log4j.core.config.plugins.Plugin;
026import org.apache.logging.log4j.status.StatusLogger;
027
028/**
029 * Formats the current date or the date in the LogEvent. The "key" is used as the format String.
030 */
031@Plugin(name = "date", category = "Lookup")
032public class DateLookup implements StrLookup {
033
034    private static final Logger LOGGER = StatusLogger.getLogger();
035    /**
036     * Looks up the value of the environment variable.
037     * @param key the format to use. If null, the default DateFormat will be used.
038     * @return The value of the environment variable.
039     */
040    @Override
041    public String lookup(final String key) {
042        return formatDate(System.currentTimeMillis(), key);
043    }
044
045    /**
046     * Looks up the value of the environment variable.
047     * @param event The current LogEvent (is ignored by this StrLookup).
048     * @param key the format to use. If null, the default DateFormat will be used.
049     * @return The value of the environment variable.
050     */
051    @Override
052    public String lookup(final LogEvent event, final String key) {
053        return formatDate(event.getMillis(), key);
054    }
055
056    private String formatDate(final long date, final String format) {
057        DateFormat dateFormat = null;
058        if (format != null) {
059            try {
060                dateFormat = new SimpleDateFormat(format);
061            } catch (final Exception ex) {
062                LOGGER.error("Invalid date format: \"" + format + "\", using default", ex);
063            }
064        }
065        if (dateFormat == null) {
066            dateFormat = DateFormat.getInstance();
067        }
068        return dateFormat.format(new Date(date));
069    }
070}