Raible Designs

Hibernate Book Review

I started doing a book review for Manning this morning. It's called Object/Relational Persistence in Java, Practical O/R Mapping with Hibernate, by Christian Bauer and Gavin King. Once again, I find myself in a time crunch with a publisher - at least I'm not writing this time. The task: read/review and critique 105 pages by tomorrow. Shouldn't be too bad, I'd better get cracking! I'll let you know what I think when I'm done.

Update: Sweet - only 86 pages (the rest is just headings). I'm halfway done. Mostly O/R Mapping concepts and comparing database types (i.e. relational vs. object-oriented) to this point. Next is mapping strategies - I hope to learn something here.

This site's performance

This site crashes more than a 16-year old trying to pick up the ladies. You can check out all the errors in my catalina.out (3+ MB) file (snapshot from last night). Mostly OutOfMemory errors causing the issues. I'm going to try and configure jikes to run as my JSP compiler, we'll see if that helps. I'd like to try it locally first (on my Win2K machine), but it looks like I have to compile it with the -encoding option to make it work. Ughhh. Why don't they have an encoding-enabled download!?

New Certification Exam from Sun

I got this notification from the Denver JUG mailing list:

The Certification team is in the process of creating a NEW certification exam!

"Sun Certified Business Component Developer for the Java 2 Platform, Enterprise Edition"

This certification is for programmers specializing in leveraging the Java 2 Platform, Enterprise Edition (J2EEtm) technologies used to develop server-side components that encapsulate the business logic of an application. Prior to beginning the Sun Certified Business Component Developer program, you must be a Sun Certified Programmer for the Java Platform (any edition).

I'm wondering if a "Business Component Developer" is a fancy name for an EJB Developer? Remember the Web Component Developer (Servlets/JSPs)?

Struts + OJB Example at SourceForge

James Mitchell has contributed a modified version of Chuck Cavaness' Beer4All Shopping cart demo to the Struts' SourceForge Project. If you're looking for an example of using OJB with Struts, this is probably your best bet. From the struts-user mailing list:

Ok, just got off the phone with Chuck.  He said he doesn't mind, so here is
the version that I have:

  http://sourceforge.net/projects/struts/

Note - This is a simple webapp and not all the features have been
implemented.  I will continue to improve the codebase over the next few
months, but this is a "use at your own risk" sample application.

To deploy "as is", you will need to configure your database connection
(repository.xml) and create a database (or change the config) called 'ojb'
with a user 'ojb' and password 'ojb'.  Next execute the sql.sql against the
new database to create the necessary data and internal tables (OJB).

Use you best judgment to deploy on your container.  I can help if using
Tomcat, Resin, or JBoss/Tomcat.  Personally, I use JBoss/Tomcat so the
unzipped/exploded war should deploy if you extract it to
server/default/deploy.

Have fun!!!

--
James Mitchell
Software Developer/Struts Evangelist
http://www.open-tools.org

BTW, there are quite a few Hibernate example apps (appfuse, hibernate and struts-resume) at the Struts SF project as well.

Locking Records in Webapps

Our tester, Roberto, started working at my day job today. This means that I've been hacking and interacting with Bugzilla all day. It's great to have someone to validate our code meets the requirements (BTW, all our requirements are kept in Bugzilla - how's that for dynamic requirements?!) So, as far as satisfying my desire to be a productive American, today has been a good day. After I ride home (~20 miles) tonight, I'll feel on top of the world. Anyway, back to the point of this post.

One of the bugs that Roberto entered was that a user could login using two separate browser sessions (same user), and blah, blah, blah. I'm sure anyone who's worked with webapps has seen this. You open a page up in both browsers, click "Save" in the first, and then "Save" in the second. The second browser overwrites the first one's changes. I've seen this bug many times, but I've never solved it, nor even tried.

I'm curious to know if any of you have solved this? I think Hibernate has a way of locking an object - but will that solve this issue? I'm willing to implement a quick solution, otherwise, I'll argue the bugs validity until I'm blue in the face. Hmmm, I wonder if I can simply use Struts' Tokens feature to solve this problem? Please hook me up if you've solved this problem in your webapps.

[ANNOUNCE] Hibernate 2.0rc1

Hibernate2 is now functionally complete! Get it at the usual place. The release notes are below.

Hibernate Changelog
===================
Changes in version 2.0 beta 5 (21.4.2003)
-----------------------------------------
* Informix support (Steve Molitor)
* fixed a bug parsing "select new ... " queries
* deprecated "object" type in favor of  mappings
* added Session.contains()
* added extra DBCP config options (?)
* SessionFactory.close() now unbinds from JNDI
* added Session.evict()
* got rid of an unnecessary SQL DELETE issued when an empty collection was dereferenced
* where attribute of collection mappings no longer ignored for deletion
* improved logging
* support polymorphic associations to "embedded" composite id classes
* various bugfixes to collection filter parameter binding
* fixed some problems with proxies introduced in earlier beta versions
* fixed bug with self-reference in the case of identity column id generation
* added hibernate.cglib.use_reflection_optimizer property
* added nonstrict-read-write cache
* fixed an SQL-generation bug in new Criteria API
* added CompositeUserType
* sequence and table id generators now aware of default-schema
* added update and insert attributes to  element
* fixed a bug with expressions like elements(foo.bar.baz) in where clause
* more efficient Set initialization (two-phase load)
* removed support for hibernate.query.imports and added  mapping element
* fixed problem in DBCP connection validation and added new config properties

I'm proud to say that this blog is now Powered By Hibernate (thanks to Dave of course)!

Cool Java Certification Site

Are you thinking about getting your Java Programmer 1.4 Certification? I am. I found JavaCertificate.com today via java.blogs. Definitely looks like a great resource for strudying. I don't know when I'll do it - probably when I get a few days to cram. I took the beta without studying and almost passed, so the "real thing" shouldn't be too bad.

[ANNOUNCE] Ant 1.5.3 Released!

It looks like I was correct in assuming that Ant 1.5.2 had a bug in it's zipfileset task. How do I know? Because it's on the fixed list for Ant 1.5.3. Via Ammai.com:

The Apache Ant Project has released version 1.5.3 of this popular Java-based build tool. This release is mainly a bug-fix one that fixes the problem with Zip files; it will also be the last one before Ant 1.6. Read more for information.

Here are the bug fixes that have been incoroporated into this release:

* <zipfileset>'s filemode would get ignored and the dirmode was used for the included files as well. As a side effect, WinZIP was unable to extract or display the files, so they seemed to be missing from the archive.

* <ftp> could use the wrong path separator when trying to change the remote working directory.

* <jar update="true"> would loose all original files if you didn't specify any nested <(zip)fileset>s and the manifest had changed.

* If you used a value starting with \ on Windows for the appxml attribute of <ear> or the webxml attribute of <war>, it would be ignored.

* Ant will no longer implicitly add Sun's rt.jar in <javac> when you use jvc and don't specify a bootclasspath.

* The prefix attribute of <zipfileset> would not generate directory entries for the prefix itself.

* starteam checkout can now handle deleted labels.

* The Unix wrapper script failed if you invoked it as a relative symlink and ANT_HOME has not been set.

Click here to go to the download page.

Maven makes it easy

If I ever migrate a project to Maven, I should probably read this article first. It's interesting to note that Maven makes it easy for project management, but not necessarily (??) for building. I know, you'll fire back that it makes it easy to build too - but if you don't have a need to manage your project, maybe you don't have a need for Maven. I find it strange that Maven is a top-level Apache project, and it hasn't even released version 1.0 yet.

Abstract: Even though Ant acts as the de facto standard for building Java programs, in many ways the tool falls short for project management tasks. In contrast, Maven, a high-level project management tool from the Apache Jakarta project, provides everything that Ant offers plus more. Java developer Charles Chan introduces Maven's features and walks you through a complete Maven project setup. [source]

DJUG Tomorrow

If you're a Java-programming Denverite, you should probably make your way down to the Denver JUG meeting tomorrow. Mike Clark (a fellow Montanan) will be presenting Bitter EJB: Learning from Antipatterns. Sounds like a great presentation - too bad I won't be able to make it. My dad flies in at 5 and I have to pick him up from the airport. We'd much rather drink microbrews and play with Abbie than learn about EJBs. Sorry Mike - hope to meet you (in person) some other day.