Handy Servlet filter

One useful feature of the later Java Servlet specifications is support for filters. Essentially, a filter can be defined declaratively in a J2EE web application descriptor to intercept responses from the application to the client according to URL patterns. The filter can then do some work on the response, before allowing it to continue. A really useful example of this, which I have just started using in just about all of my J2EE webapps, is the trim filter. [continues...]

Paul Walk , October 31, 2004

Tagged with: ,

Laszlo goes open-source

Laszlo technology is an open source XML-native platform for building rich client applications that deliver a breakthrough online user experience. Laszlo's single-page Web experience increases customer conversion rates, improves brand loyalty and ultimately impacts the bottom line. Having a long history of developing web applications, my colleagues and I are aware of the gradual growth in interest in the paradigm of the Rich Internet Applications (RIA). Now that there is a serious open-source solution, it might be time to realise some of our aspirations in this area. [continues...]

Paul Walk , October 11, 2004

Tagged with:

Java Package Processes All RSS Formats

Several Java packages work with RSS. Some can read certain formats, while others can write them as well. The class this article features reads all known RSS formats and outputs the converted data in the 2.0 format. Vlad Patryshev on This looks useful - I haven't tried this out yet but I probably will in the near future. At the very least it could be deployed to sit between remote content and a local presentation layer, allowing the presentation technology to concern itself with a single format. [continues...]

Paul Walk , July 8, 2004

Tagged with: , ,

Aspect Oriented Programming without the buzzwords....?

After the AOP panel at the TSS Java Symposium had finished, Ted Neward threw out a challenge to some of the participants to come up with "an explanation of AOP without resorting to buzzwords." I've been mulling that around in my head for a few days now... What follows should be considered an early version of an attempt to explain what's at the heart of AOP (from my perspective), without resorting to any buzzwords. [continues...]

Paul Walk , June 8, 2004

Tagged with:

What Now for JDO?

The EJB 3.0 expert group seems to have handed JBoss the EJB application server market on a silver platter. Several weeks ago at TheServerSide Java Symposium in Las Vegas the EJB expert group announced its decision to shelve the current entity bean architecture and focus on the lightweight persistence of Plain Old Java Objects (POJOs). Specifically, it decided to use Hibernate as the persistence mechanism in EJB 3.0. Hibernate is an open source object/relational mapping solution that joined the JBoss Group last year. [continues...]

Paul Walk , June 3, 2004

Tagged with: ,

More on Using Open Office to convert MS documents

Viggo Navarsete made the following comment on my recent post about using to convert MS Word documents. ...I have a similar problem at my project, where we want to embed powerpoint presentations into an existing pdf-document. A solution could perhaps be to use openoffice to convert the powerpoint presentation into jpegs, and then embed these pictures into the pdf? How is it possible to convert powerpoint to jpegs using openoffice in java? [continues...]

Paul Walk , May 12, 2004

Pocket WIFI Rules!

I went out a couple of weeks ago and treated myself to a new palmtop - Sony's Clie TJ37 I must say I'm very pleased with it. Having had three PalmOS devices before, the main new feature I wanted was WIFI access. This is because my 3 month old son, Joe, seems to sense it when I open my laptop and has usually started crying before my Linux system has fully booted-up. [continues...]

Paul Walk , May 7, 2004

Tagged with: ,

Using Open Office to convert MS Word documents

Rickard Öberg recently posted a request for suggestions about using Java to convert MS word docs into HTML. I have been doing some work on this lately using the freely available, open-source to do the hard parts, making calls to a running OpenOffice server from within my Java code. It seems that there is some more interest in doing this from the Java community at large, so I am posting some source code here for anyone who is interested. [continues...]

Paul Walk , April 26, 2004

Tagged with:

Eclipse 3.0 Milestone build 8

I have been using Eclipse as my main Integrated Development Environment for about 18 months now, and have seen it go from strength to strength during this period. Initially, I was hooked by the idea of it more than it's functionality, although it's support for Java development and CVS integration has been reasonably usable. What really attracted me to it was: it is opensource and free for use it is being very actively developed it is extremely extensible With the last few releases of the new 3. [continues...]

Paul Walk , April 6, 2004

University hits PeopleSoft with 10M Lawsuit

"The lawsuit, filed Jan. 30 in an Ohio state court, claims that the student administration applications were 'vaporware' when the project began in 1997 and that the module for managing financial aid remains unusable even now. Through the attorney general, Cleveland State is charging PeopleSoft with fraud, breach of contract, negligent misrepresentation and four other counts." First time I have come across a lawsuit of this magnitude coming from the public sector. [continues...]

Paul Walk , March 30, 2004

Ad hoc integration of Web Services

"The Unix idea of piecing together solutions from reusable parts has morphed into XML-based, service-oriented architecture. This time around, though, it's all happening on the Web, in an environment where everybody can compose simple and popular tunes. When technologists forget that, I hope users will administer the dope slap we deserve." Jon Udell on This resonated with me. Recently, as part of my work at a London University, I re-engineered a legacy enterprise-wide web application called MISLine, moving it from a straightforward ColdFusion app into a set of Java Beans / servlets / JSPs and deploying it in a J2EE cluster. [continues...]

Paul Walk , March 19, 2004

Tagged with: , , ,

Web Services like Unix's Software Tools?

"...I saw a large division between the concept of software and service. But that's changed now, I think - the lines have blurred because the Internet has proven its reliability." Russell Beattie Notebook More on the potential for ad hoc use of Web Services, viewing Web Services as well-defined, small utilities in the UNIX model. This was previously published at and was retrieved from the Internet Archive. [continues...]

Paul Walk , March 19, 2004

Tagged with:

RSS meets BitTorrent - Syndicating Multimedia

"A demo publishing system launched Friday by a popular programmer and blogger merges two of this season's hottest tech fads -- RSS news syndication and BitTorrent file sharing -- to create a cheap publishing system for what its author calls "big media objects." The hybrid system is meant to eliminate both the publisher's need for fat bandwidth, and the consumer's need to wait through a grueling download." Wired News [continues...]

Paul Walk , March 17, 2004

Tagged with: ,

For JDO, the Time Is Now

"Without a dominant proprietary solution and with EJB in disarray, the software industry has a significant vacuum in the Java persistence solution market. Many are looking to the next best standard. With the Java Data Objects (JDO) 2.0 specification under way, the timing is right for JDO to seize this opportunity. " Bruce Tate on Bruce's conclusions are interesting. Despite developing J2EE apps for a couple of years now, I have not found a compelling case for developing Entity Beans, but would welcome a 'safe', standard, persistence solution. [continues...]

Paul Walk , March 15, 2004

Tagged with: ,

MySQL - Free and Open Source Software (FOSS)

"...a more flexible open source licensing program for the MySQL client libraries, which are used to access the MySQL database from within applications. Previously usable under either a commercial or a GPL open source license, MySQL has developed its Free and Open Source Software (FOSS) Exception policy enabling the libraries to be used under other open source licensing formats, such as Apache and Artistic." Infoworld This is an interesting development for MySQL, which now has both commercial and free offerings. [continues...]

Paul Walk , March 15, 2004

Tagged with:

Team Blogging

I've been asked to introduce blogging to my place of work for a team of myself and six colleagues. Our activities are wide-ranging within the sphere of web-based service delivery and development, so the team might be described as fairly loosely-coupled. The idea is that blogging will be a potential way of improving understanding of what colleagues are focussed on at any one time. The discussion about how to implement this was interesting, and the following was decided: [continues...]

Paul Walk , May 2, 2003

Tagged with: , ,

Easy News Topics

Easy News Topics (ENT) is a new specification for defining topic meta-data in RSS2.0 news feeds. As the authors explain: The goals of ENT are to: be as simple to implement as possible represent topics sufficiently that they be useful in enabling smart aggregators (e.g. filtering, recombining feeds, etc...) allow, via linking, use of more powerful and flexible standards where appropriate I have implemented some of the ENT specification into a new RSS2. [continues...]

Paul Walk , April 25, 2003

Tagged with: ,

Regular Expression Library

This is a useful, searchable resource of regular expression examples. It covers expressions for validating such formatted data as email addresses, UK postcodes, dates etc. Thanks to David Gammel's High Context for this. This was previously published at and was retrieved from the Internet Archive.

Paul Walk , April 4, 2003

Tagged with:


I've become a big fan of Channel 4 news - in terms of coverage of the war in Iraq they certainly don't take the Government/BBC line. I highly recommend a Channel 4 news service called Snowmail - John Snow's personal daily news roundup by email. It's personal tone is well suited to email delivery rather than, say, a syndicated RSS feed. Of course he could blog this stuff instead.... This was previously published at http://blog. [continues...]

Paul Walk , March 31, 2003

Waiting for the B52s to Arrive

The most disturbing news today has come from Al Jazeera, they said that nine B52 bombers have left the airfield in Britain and flying (presumably) towards Iraq, as if they would be doing a spin around the block. Anyway they have 6 hours to get here. [...] 2 more hours untill the B52's get to Iraq.... Salam Pax's blog This is compelling reading - a first hand account of daily life in Baghdad from a local blogger. [continues...]

Paul Walk , March 23, 2003