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