March 2010 Archives

Spring Timer's are great if you need a job or task to run on a fixed interval.  For example, if you need a bean to wake up and run itself every 30-minutes.  But what if you need finer control over the scheduling of a timer?  Say you need a job to run every morning at 3AM, regardless of when the JVM is started.  Or, say you need a bean to run "every half hour between the hours of 8 AM and 10 AM on the 5th and 20th of every month."  You won't get that type of granular control with a straight-up Spring Timer.

Meet Quartz, a full-featured, open source job scheduling service that can be integrated with, or used along side virtually any Java EE or Java SE application.  Similar to a native UNIX Cron job, Quartz lets you define powerful CronExpression's that give you very precise control over when a job or task is started and on what interval.

Setting up Quartz with your Spring powered web-application is easy.

In 2008, my girlfriend bought me a Krups KM7000 Grind-and-Brew Coffee Maker for Christmas.  I love it, it grinds and brews an incredible pot of high quality coffee for me each morning.  This past weekend (about 15-months since I got it), my KM7000 unexpectedly stopped brewing mid-cycle.  And to make matters worse, the one-year manufacturers warranty period already expired.  Well, I wasn't about to let this one get away, so I decided to open it up and give it a look-see.  After all, shouldn't a high-end coffee maker last a little longer than just over a year?

With a little effort and some engineering know-how, I found the troublemaker part and repaired my coffee maker.  My KM7000 is as good as new.  Here's how I did it ...

Setting up your own SVN source control server is surprisingly easy.  At home, I recently setup an SVN server in a CentOS 5.4 virtual machine with Apache 2.2 and mod_dav_svn.  With a little work, I had a secure and fully functional SVN server up and running in about 20 minutes.

Note that this HOWTO is specific to CentOS/RHEL/Fedora.  The location of configuration files, and other tools, might be different depending on your Linux distro.  For the most part though, everything should be pretty similar and you should be able to figure it out.

This weekend I setup my own SVN source control server running inside of a CentOS 5.4 virtual machine (fun project, another blog post on this to come soon here's my how to setup your own SVN server post).  Once my new SVN server was setup and ready to roll, I tried checking out one of the repositories.  From the nearest command line, I started typing "svn co http://192.168.1." ... damn, what was the IP-address of my local SVN server again?  I just picked an IP-address about 15 minutes ago during my CentOS install, but already forgot it!  Ok, time to setup a decent local DNS server for my home network.  Since 2006, I've been limping along manually editing my /etc/hosts files on multiple machines and memorizing the IP-addresses of critical devices on my network.  Looking back, this was just plain silly.