/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements.  See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License.  You may obtain a copy of the License at *  *      http://www.apache.org/licenses/LICENSE-2.0 *  * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package org.apache.log4j.helpers;import java.util.Date;import java.util.Calendar;import java.util.TimeZone;import java.text.FieldPosition;import java.text.ParsePosition;import java.text.DateFormat;/**   Formats a {@link Date} in the format "HH:mm:ss,SSS" for example,   "15:49:37,459".      @author Ceki G&uuml;lc&uuml;   @author Andrew Vajoczki       @since 0.7.5*/public class AbsoluteTimeDateFormat extends DateFormat {   private static final long serialVersionUID = -388856345976723342L;  /**     String constant used to specify {@link     org.apache.log4j.helpers.AbsoluteTimeDateFormat} in layouts. Current     value is <b>ABSOLUTE</b>.  */  public final static String ABS_TIME_DATE_FORMAT = "ABSOLUTE";  /**     String constant used to specify {@link     org.apache.log4j.helpers.DateTimeDateFormat} in layouts.  Current     value is <b>DATE</b>.  */  public final static String DATE_AND_TIME_DATE_FORMAT = "DATE";  /**     String constant used to specify {@link     org.apache.log4j.helpers.ISO8601DateFormat} in layouts. Current     value is <b>ISO8601</b>.  */  public final static String ISO8601_DATE_FORMAT = "ISO8601";  public  AbsoluteTimeDateFormat() {    setCalendar(Calendar.getInstance());  }    public  AbsoluteTimeDateFormat(TimeZone timeZone) {    setCalendar(Calendar.getInstance(timeZone));  }  private static long   previousTime;  private static char[] previousTimeWithoutMillis = new char[9]; // "HH:mm:ss."  /**     Appends to <code>sbuf</code> the time in the format     "HH:mm:ss,SSS" for example, "15:49:37,459"     @param date the date to format     @param sbuf the string buffer to write to     @param fieldPosition remains untouched    */  public  StringBuffer format(Date date, StringBuffer sbuf,		      FieldPosition fieldPosition) {    long now = date.getTime();    int millis = (int)(now % 1000);    if ((now - millis) != previousTime) {      // We reach this point at most once per second      // across all threads instead of each time format()      // is called. This saves considerable CPU time.      calendar.setTime(date);      int start = sbuf.length();            int hour = calendar.get(Calendar.HOUR_OF_DAY);      if(hour < 10) {	sbuf.append('0');      }      sbuf.append(hour);      sbuf.append(':');            int mins = calendar.get(Calendar.MINUTE);      if(mins < 10) {	sbuf.append('0');      }      sbuf.append(mins);      sbuf.append(':');            int secs = calendar.get(Calendar.SECOND);      if(secs < 10) {	sbuf.append('0');      }      sbuf.append(secs);      sbuf.append(',');            // store the time string for next time to avoid recomputation      sbuf.getChars(start, sbuf.length(), previousTimeWithoutMillis, 0);            previousTime = now - millis;    }    else {      sbuf.append(previousTimeWithoutMillis);    }            if(millis < 100)       sbuf.append('0');    if(millis < 10)       sbuf.append('0');        sbuf.append(millis);    return sbuf;  }  /**     This method does not do anything but return <code>null</code>.   */  public  Date parse(String s, ParsePosition pos) {    return null;  }  }