ISO8601 allows a lot of variation in date/time formats dependent on the specific application. On the point of decimal separator for the fractional part of a time the spec states:
"If necessary for a particular application a decimal fraction of hour, minute or second may be included. If a decimal fraction is included, lower order components (if any) shall be omitted and the decimal fraction shall be divided from the integer part by the decimal sign specified in ISO 31-0: i.e. the comma [,] or full stop [.]. Of these, the comma is the preferred sign." Since the specification clearly stated a "preference" for the decimal fraction separator, we had chosen to use a comma some time ago and not the local-preferred decimal separator. Although the decision is not up to me (and this is clearly a minor point and seem a bit nit-picking), I would encourage following the preference stated in the specification in this area. Of course, that's must my opinion. I could be wrong. Best regards, Jim Cakalic > -----Original Message----- > From: Andrew Vajoczki [mailto:[EMAIL PROTECTED]] > Sent: Friday, January 18, 2002 12:05 PM > To: Log4J Developers List > Subject: [PATCH] ISO8601DateFormat/%d{ISO8601} speed optimization > > > Overall Log4J logging speed with typical ISO date format strings > (like "%p %t %d{ISO8601} %c %m%n") is roughly 50% faster > with this date string caching optimization (at least on > my JDK 1.3/Windows machine). > > This puts typical logging using %d{ISO8601} closer to > as %r (relative) timings. > > Although I've tested it and it seems fine, more testing never hurts. > > diff -u made against > jakarta-log4j-1.2alpha6/src/java/org/apache/log4j/helpers/ISO8 601DateFormat.java > > -Andrew Vajoczki > > --- ISO8601DateFormat.java.orig Thu Jan 17 19:52:28 2002 > +++ ISO8601DateFormat.java Fri Jan 18 12:20:26 2002 > @@ -41,6 +41,10 @@ > ISO8601DateFormat(TimeZone timeZone) { > super(timeZone); > } > + > + static private Object lastTimeLock = new Object();; > + static private long lastTime; > + static private char[] lastTimeString = new char[20]; > > /** > Appends a date in the format "YYYY-mm-dd HH:mm:ss,SSS" > @@ -52,37 +56,87 @@ > StringBuffer format(Date date, StringBuffer sbuf, > FieldPosition fieldPosition) { > > - calendar.setTime(date); > - > - int year = calendar.get(Calendar.YEAR); > - sbuf.append(year); > + long now = date.getTime(); > + int millis = (int)(now % 1000); > > - String month; > - switch(calendar.get(Calendar.MONTH)) { > - case Calendar.JANUARY: month = "-01-"; break; > - case Calendar.FEBRUARY: month = "-02-"; break; > - case Calendar.MARCH: month = "-03-"; break; > - case Calendar.APRIL: month = "-04-"; break; > - case Calendar.MAY: month = "-05-"; break; > - case Calendar.JUNE: month = "-06-"; break; > - case Calendar.JULY: month = "-07-"; break; > - case Calendar.AUGUST: month = "-08-"; break; > - case Calendar.SEPTEMBER: month = "-09-"; break; > - case Calendar.OCTOBER: month = "-10-"; break; > - case Calendar.NOVEMBER: month = "-11-"; break; > - case Calendar.DECEMBER: month = "-12-"; break; > - default: month = "-NA-"; break; > + synchronized (lastTimeLock) { > + if ((now - millis) != lastTime) { > + // 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 year = calendar.get(Calendar.YEAR); > + sbuf.append(year); > + > + String month; > + switch(calendar.get(Calendar.MONTH)) { > + case Calendar.JANUARY: month = "-01-"; break; > + case Calendar.FEBRUARY: month = "-02-"; break; > + case Calendar.MARCH: month = "-03-"; break; > + case Calendar.APRIL: month = "-04-"; break; > + case Calendar.MAY: month = "-05-"; break; > + case Calendar.JUNE: month = "-06-"; break; > + case Calendar.JULY: month = "-07-"; break; > + case Calendar.AUGUST: month = "-08-"; break; > + case Calendar.SEPTEMBER: month = "-09-"; break; > + case Calendar.OCTOBER: month = "-10-"; break; > + case Calendar.NOVEMBER: month = "-11-"; break; > + case Calendar.DECEMBER: month = "-12-"; break; > + default: month = "-NA-"; break; > + } > + sbuf.append(month); > + > + int day = calendar.get(Calendar.DAY_OF_MONTH); > + if(day < 10) > + sbuf.append('0'); > + sbuf.append(day); > + > + sbuf.append(' '); > + > + 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); > + > + // use current locale's decimal separator > + sbuf.append(new > java.text.DecimalFormatSymbols().getDecimalSeparator()); > + > + // store the time string for next time to avoid recomputation > + sbuf.getChars(start, sbuf.length(), lastTimeString, 0); > + lastTime = now - millis; > + } > + else { > + sbuf.append(lastTimeString); > + } > } > - sbuf.append(month); > - > - int day = calendar.get(Calendar.DAY_OF_MONTH); > - if(day < 10) > - sbuf.append('0'); > - sbuf.append(day); > - > - sbuf.append(' '); > - return super.format(date, sbuf, fieldPosition); > - } > + > + 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>. > @@ -92,3 +146,4 @@ > return null; > } > } > + > <font size="1">Confidentiality Warning: This e-mail contains information intended only for the use of the individual or entity named above. 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