    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.lang.management.ManagementFactory;
    020
    021    import org.apache.logging.log4j.core.LogEvent;
    022    import org.apache.logging.log4j.core.config.plugins.Plugin;
    023
    024    /**
    025     * Returns the relative time in milliseconds since JVM Startup.
    026     */
    027    @Plugin(name = "RelativeTimePatternConverter", category = PatternConverter.CATEGORY)
    028    @ConverterKeys({ "r", "relative" })
    029    public class RelativeTimePatternConverter extends LogEventPatternConverter {
    030        /**
    031         * Cached formatted timestamp.
    032         */
    033        private long lastTimestamp = Long.MIN_VALUE;
    034        private final long startTime = ManagementFactory.getRuntimeMXBean().getStartTime();
    035        private String relative;
    036
    037        /**
    038         * Private constructor.
    039         */
    040        public RelativeTimePatternConverter() {
    041            super("Time", "time");
    042        }
    043
    044        /**
    045         * Obtains an instance of RelativeTimePatternConverter.
    046         *
    047         * @param options options, currently ignored, may be null.
    048         * @return instance of RelativeTimePatternConverter.
    049         */
    050        public static RelativeTimePatternConverter newInstance(
    051            final String[] options) {
    052            return new RelativeTimePatternConverter();
    053        }
    054
    055        /**
    056         * {@inheritDoc}
    057         */
    058        @Override
    059        public void format(final LogEvent event, final StringBuilder toAppendTo) {
    060            final long timestamp = event.getTimeMillis();
    061
    062            synchronized (this) {
    063                if (timestamp != lastTimestamp) {
    064                    lastTimestamp = timestamp;
    065                    relative = Long.toString(timestamp - startTime);
    066                }
    067            }
    068            toAppendTo.append(relative);
    069        }
    070    }