1   /**
2    * Logback: the reliable, generic, fast and flexible logging framework.
3    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
4    *
5    * This program and the accompanying materials are dual-licensed under
6    * either the terms of the Eclipse Public License v1.0 as published by
7    * the Eclipse Foundation
8    *
9    *   or (per the licensee's choosing)
10   *
11   * under the terms of the GNU Lesser General Public License version 2.1
12   * as published by the Free Software Foundation.
13   */
14  package ch.qos.logback.classic.pattern;
15  
16  import ch.qos.logback.classic.spi.ILoggingEvent;
17  
18  public class RelativeTimeConverter extends ClassicConverter {
19  
20      long lastTimestamp = -1;
21      String timesmapCache = null;
22  
23      public String convert(ILoggingEvent event) {
24          long now = event.getTimeStamp();
25  
26          synchronized (this) {
27              // update timesmapStrCache only if now != lastTimestamp
28              if (now != lastTimestamp) {
29                  lastTimestamp = now;
30                  timesmapCache = Long.toString(now - event.getLoggerContextVO().getBirthTime());
31              }
32              return timesmapCache;
33          }
34      }
35  }