tomcat-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From tobias.dittr...@t-online.de (Tobias Dittrich)
Subject Re: about singletons (ot)
Date Wed, 29 Jan 2003 20:17:16 GMT

The reason why you don't want to use synchronized methods is that a
synchronized block can only be executed by one thread at a time. Every other
thread wanting to access this method will be blocked during this time (well,
basically). So you want to try to keep the synchonized blocks as small as
possible.

Having said that I wonder weather performance is an issue in the singleton
vs only-static discussion. Is there a significant difference in execution
speed? After all one has to make one additional method call every time when
accessing a singleton method (the getInstance() which is  synchronized,
too). And since we're off topic anyway: is a call to a static method faster
than a "normal" one to an object (well, I mean the overhead from the method
call, not the execution speed of the method body ... )?


Cheers
Tobi



From: "Erik Price" <eprice@ptc.com>
To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
Sent: Wednesday, January 29, 2003 1:46 PM
Subject: Re: about singletons (ot)


>
>
> Mike Jackson wrote:
> > The difference is that if you use a singleton there's one instance.  If
> > everything
> > is static then you only have one copy.  Usually when you use a singleton
> > it's to
> > control access to some resource, the intent is that you use the
singleton
> > and some
> > synchronized calls (note I don't mean synchronized methods, but
synchronized
> > code
> > blocks) to control threads using that resource.
>
> Why could you not use synchronized methods?
>
>
>
> Erik


---------------------------------------------------------------------
To unsubscribe, e-mail: tomcat-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: tomcat-user-help@jakarta.apache.org


Mime
View raw message