Skip to main content


Threaded chat article and demo

While nothing major, managing threaded conversations in chat has bothered me for quite a while. Yesterday I had an idea on how to improve matters:
Works using existing chat infrastructure. Needs only augmented clients.Plays well even if other party uses a non-thread aware chat tool.Separates threads automatically based on interaction patterns.I've written an article and have created an online demo about it. Discussion welcome.

GMail diffs to find quoted text

GMail is really so cool. I think rather than just relying on quotation marks (> and such), it strips them and then diffs the message to its predecessors to find common chunks. I saw that in action when I sent an updated patch to a mailing list. In both versions, there were no quotation marks, but the second message, viewed in GMail, showed just what had changed versus the first message, the rest being hidden behind "--Show quoted text--" markers.

Using Throwable to trace the origin of an object

When using components decoupled by queues or other intermediate data stores, it can be a pain to trace the origin of faulty data in the queue. In languages with decent support for stack traces, however, it's easy. In Java, you just add a temporary field public final Throwable createdBy = new Throwable(); to the class in question. Or, if you need to know who enqueued it where, you vary the creation of the Throwable accordingly. (See example 8-5 of logging in the Red Hat Web Application Framework, too.)

Local Builder Pattern Broken in Java?

Time and again, when I want to break up a longish Java method into smaller parts, I find myself wishing back the by-reference parameters and access to surrounding local procedure variables of Pascal. Now, I know that the discipline of trying to always pass all required arguments explicitly, and to not rely on changes to by-ref params is often helpful. Nevertheless, sometimes it gets in the way. One fairly clutter free approach to get Pascal's features back goes like this:
public interface LocalBuilder {
T build();
and then:
public MyClass computeIt() {
new LocalBuilder() {
final int input1 = ...;
final int input2 = ...;
int state1 = ...;
int state2 = ...;

public MyClass build() {
return result();

private void stepOne() { ... }
private void stepTwo() { ... }
private MyClass result() { ... }

While this basically works, it has a few problems:
Exceptions thrown by build() must be declared already on the interface. This is a seriou…

Documentation Driven Development - Other Takes On The Theme

I googled for "Documentation Driven Development" and came up with a number of links (why the heck did I not do this sooner?).
SpliceIt seem to be doing it, but don't cite tests. There is no mention of integration with use-case-level tests.Vincent Massol had the experience when writing books about frameworks - always improved the underlying code. The message is: you have to be serious about writing good docs. Otherwise the effect is lost.Korby Parnell just thinks about it, but some comments point to people with experience doing it.IEEE has an article about DDD for real time systems. Also seems to take it as far as code-generation. I haven't read it.Miguel dos Santos has little to add, but there is a nice comment by someone called "Tania" about applying the idea of documenting the "why" more generally.In the groups, I got:
Ilja Preuss's take is a bit too limited for me. In my experience, good DDD docs focus on tasks, not classes and methods.Michel…