David Berlind has an interesting post about the potential of Derby as an offline storage mechanism for thin-client web-apps. I can see the potential and an awful lot of difficulties as well. Might I suggest the perfect integration point for this kind of thing is a really cool Java WYSIWYG editor?

Hey Andrew (CEO of Ephox and a big fan of offline editing), can I have some time to try and prototype this on Ephox’s internal wiki? You could edit your wiki pages offline easily…

Setting the system look and feel is a common task in applications and if you’re shooting for 100% test coverage, it’s problematic because it uses two static methods and has checked exceptions. Typically you have something like:

void setNativeLookAndFeel() {

    try {

        UIManager.setLookAndFeel(

        UIManager.getSystemLookAndFeelClassName());

    } catch (Exception e) {

        // Handle exception somehow.

    }

}

As far as I know, there’s no way to write a test that doesn’t also exercise UIManager, so we’ll have to live with that, but we can test that the UI is set and the exception handled.

When you work with legacy code, it’s easy to fall into the trap of thinking that because you can’t atomically test it that you should refactor it and add tests. This is a mistake. You should write integration tests, then refactor it, then write atomic tests. Even when the refactoring seems simple, it’s still possible to stuff it up.

Most code can have integration tests written for it, even when it wasn’t designed for testing. In some cases the tests may not be able to cover everything but should give you at least a foundation to work from. Just make sure that as you write the tests you note down the things you couldn’t write an automated test to cover and make sure you do add a test for them after your refactoring.

The basic principle of TDD is that you write the test first and then write the code required to make that test pass. There’s more to it though if you expect to see all the benefits. If you drive your development from integration tests instead of atomic tests, you’ll wind up with highly coupled code again and because it grows gradually without up-front planning, it’s often harder to understand.

If however, you drive your development by atomic tests, you are very strongly encouraged to decouple your code whenever possible because mocking out dependencies is so annoying and time consuming (plus the more you have to mock, the more brittle your tests tend to be).

I’ve finally gotten around to upgrading to WordPress 2. Mostly I held off because it was going to destroy my integration of EditLive! for Java (I didn’t bother learning about plugins, just edited the WordPress source code). This time around I’ve integrated ELJ via a plugin, but the plugin API doesn’t make it particularly simple. Why is there no action for generating the editor? Shouldn’t it have been reasonably obvious that people might want alternative editors?

There seems to be a great demand for HTML documents that don’t include white-space between paragraphs – similar to going into the paragraph formatting in Word and setting space before and space after to zero. This is very simple to achieve in HTML, but people just keep coming up with strange ways to attempt to achieve it.

The most common way people try to get around the problem is by putting their entire document in one P tag and using BRs. You can pick these people because they set their HTML editors to insert a BR on enter instead of inserting a new paragraph. The end result looks right in all browsers but destroys the semantic structure of the document. I imagine it would be much harder to navigate through the document using a screen reader too, since skipping paragraphs seems like a nice way to skim. The problem people most often run into with this approach is that their editor still treats the whole big block as a paragraph, so when they apply a heading style the entire document becomes a H1 tag with a bunch of BRs.

Useful tool for writing performance tests: Japex.  Must remember to use that when we do our next round of profiling. Doug’s suggestion is that once we identify a bottleneck in the code, we write a performance test for it with Japex then try to optimize it until we reach the desired performance level. I’m not sure that our codebase is likely to see performance regressions in the same area again (I can’t ever recall having to reoptimize the same section of code), however having the test would be able to quantify how much of a performance benefit we get which would be a useful metric to know.

As part of planning our wedding next year, the lovely Janet and I have begun looking into photographers. It seems that at least some photographers apply the same dodgy lock-in practices as software companies do by holding onto the copyright of the pictures they take at your wedding and forcing you to go back to them for reprints.

Apart from the fact that I’m somewhat uncomfortable with anyone owning the photographic memories of our wedding, the terms and conditions from one particular photographer are just ridiculous. This particular photographer will quite happily provide you with a DVD of all the photos they take in high resolution – you just have to wait two and a half years after your wedding and pay an extra $750. I’m not sure what happens if he happens to be hit by a bus in those two years or if for some other reason he goes out of business.  As we left our meeting with this photographer I felt quite uneasy about this terms – just feeling that something was wrong, however as I thought more about it, I thought of more and more situations where it would really come back to bite us.

There is one major problem with test driven development – it makes it easy to get lost. When you don’t use TDD, you tend to run your application a whole lot to see what effect your latest code has made. With test driven development, you run your atomic tests a whole lot instead. The trouble is, if your unit tests are taking you in the wrong direction, it can be a long time before you find out.

I’ve been developing some custom views (javax.swing.text.View subclasses) in the last few days. These are right up the alley of GUI code that people tend to find difficult to test but I’ve been pushing forward with test driven development with a fair bit of success. The main approach I’ve been using is to mock out pretty much everything the view interacts with and test it’s logic more than it’s actual rendering. In fact, this particular view doesn’t do any rendering of it’s own, but it does do a lot of layout of child views etc.

Note to self: I must read up on Andy Roberts’ Delta Web proposal and get involved. It looks decidedly useful.

Most code bases have some kind of code debt associated with them, legacy code bases tend to have lots of code debt. The good news is, paying back that code debt isn’t a complete time sink – it has definite advantages too. Obviously, reducing code debt tends to make the team go faster, but it also tends to fix bugs.

Quite often where there is debt, there is not just a lack of maintainability but actual bugs that are frustrating your users. By cleaning up the code, you will often fix those bugs without any special effort to do so – it just happens because of the simplified design.