[Building Sakai] Sakai Time locking

[Steve Swinsburg]

I would +1000 TimeService and Time to die as I have had issues with it as well.

The problem is that there are a lot of the older type tools that still use it, and that interconnect, so would need to be carefully updated.

cheers,
Steve


On 16/07/2013, at 1:11 AM, David Horwitz <David.Horwitz at uct.ac.za> wrote:

> Hi All,
> 
> Digging into some performance behaviour were seeing a number of blocked threads creating Time objects:
> 
> ajp-bio-8009-exec-2872" daemon prio=10 tid=0x00007fb79e6ff800 nid=0x744c waiting for monitor entry [0x00007fb771b32000] 
> java.lang.Thread.State: BLOCKED (on object monitor) 
> at org.sakaiproject.time.impl.MyTime.<init>(MyTime.java:67) 
> - waiting to lock <0x00000007cd4fed90> (a java.text.SimpleDateFormat) 
> at org.sakaiproject.time.impl.BasicTimeService.newTimeGmt(BasicTimeService.java:257) 
> at org.sakaiproject.message.impl.BaseMessageService$BaseMessageHeaderEdit.<init>(BaseMessageService.java:4067
> 
> 
> The code this relates to is the synchronize block:
> 
> public MyTime(BasicTimeService timeService, String str)
> {
> this.timeService = timeService;
> // use formatter A: yyyyMMddHHmmssSSS
> Date d = null;
> synchronized (timeService.M_fmtA)
> {
> ParsePosition pos = new ParsePosition(0);
> d = timeService.M_fmtA.parse(str, pos);
> }
> m_millisecondsSince = d.getTime();
> }
> 
> 
> Presumably this is synchonized as DateFormats are not thread safe. This seems to strengthen the case for a more aggressive removal of the Sakai Time object in favour or java.util.Date or joda-time, as we don't see how this could be have good performance characteristics.
> 
> Any differing views? ;-)
> 
> D
> UNIVERSITY OF CAPE TOWN 
> 
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