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.lookup;
018    
019    import java.text.DateFormat;
020    import java.text.SimpleDateFormat;
021    import java.util.Date;
022    
023    import org.apache.logging.log4j.Logger;
024    import org.apache.logging.log4j.core.LogEvent;
025    import org.apache.logging.log4j.core.config.plugins.Plugin;
026    import 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")
032    public 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.getTimeMillis(), 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    }