Wow! Has it been one year already? Yes! Today marks exactly one year since we first published a short introduction to the blog (Starting Up). Since then we’ve had more than 90,000 unique visitors. In this celebration post, I’d like to re-cap the year, and bring you a list of the three most successful articles we’ve written over this past year.

1. Why Gentoo Shouldn’t be on Your Server (~40,000 views)

Our by far most popular article during the course of the year was an article called “Why Gentoo Shouldn’t be on Your Server.” Not only did this article catch a great deal of attention on blogs and forums around the world, but it even made it to Slashdot. The reason why this article became so widely read was because it discussed something that apparently is a very sacred Open Source-topic: Gentoo Linux. This Linux-distribution is considered by many as the most elite and advanced distribution because of its endless abilities to customize for you own needs. Our article took a look at how that kind of flexibility fares in the server world, and how it worked out for us after a year of use. We wrote that while we liked the distribution, it didn’t seem like the best idea to run it on a production server. Gentoo could be a great distribution for the lab-machine where you would want to stay updated with the most recent versions of everything, but for our production servers we would rather have something more stable that requires less frequent updates (only security updates), such as FreeBSD or Ubuntu (LTS).

2. Building a modern IT infrastructure for a small company (10 clients) with a sub-$3,000 budget (~18,000 views)

Interestingly enough, this article made it to the top without being mentioned on any of the big blogs: instead the majority of our visitors found the article through Stumbleupon. The article is the first in a series of two articles about how to create a modern IT infrastructure from scratch with an extremely small budget. To achieve this, we heavily rely on Open Source software for all parts of the organization. Without going into details, we utilize a software suit called LTSP to turn a set of cheap old computers into modern thin clients.

In the first article, we talk about the entire concept of using LTSP and how everything fits together. In the second article (Deploying the sub-$3,000 IT-infrastructure), we actually deploy this concept in a real company. Not only do we discuss how we ended up setting everything up, but we also provide detailed information on the exact hardware used, how it was configured, and what the actual cost was.

3. Bye Bye Binders, I Won’t Miss You at All (~10,000 views)

This article was a bit different from the articles we usually write, but it turned out to draw quite a lot of attention and it made it all the way to Lifehacker. In this article we wrote about how your could turn those ugly binders in your bookshelf into something more useful and pretty — a set of PDF-files. If you do have a scanner with Automatic Document Feeder (ADF), this guide helps you organize all of those documents into conveniently accessible PDF-files.

So what did we learn over this past year?

• Digg is overrated. If none of the few power-diggers ‘diggs’ your post, you probably won’t receive any noticeable traffic.
• Stumbleupon is very sporadic and unpredictable. Even though no major blog wrote about our LTSP article, it’s still the second most visited article on our blog.
• Blogging takes time. Although we really enjoy writing most of the articles here, it does take a whole lot of time.
• You need quite a bit of traffic to make any money of a blog. Even though we’ve had over 100,000 visits this past year, the revenue we’ve made in advertisement doesn’t even cover our hosting costs.
• It takes time to establish a user-base. Nowadays we receive more traffic in a couple of days than we did in a month in the beginning.

We hope that you’ve enjoyed the first year of Playing With Wire, and that you will enjoy another year with our technology, internet and startup articles.

Parallels makes a virtual PC type of software for the Mac which allows you to run Windows on the Mac. Great software, but the company has a little bit of a history of quality control problems. Today the company launched a new design of their website. Unfortunately the company forgot about supporting the default Mac browser, Safari!

Nothing big: a drop down menu is showing out of place. The site actually seems to start working after you resize it for the first time, or click a single link. It’s likely to be fixed by the time many people read this, but it’s still a little bit ironic that a company with a major Mac market would not check their site in Safari.

           

We had a couple of hours of downtime this morning as a new diesel generator was installed at Playing With Wire’s hosting location. Sorry about that.

SwtCallback 0.1 was released only a little more than a week ago, but that’s not stopping us from releasing 0.2 today! In line with the original philosophy, SwtCallback has been extended to again reduce clutter and deep nesting in your Java code. This time SwtCallback attacks the Runnable interface.

As I wrote in my release post about SwtCallback, SwtCallback is a java library for SWT applications which adds an alternative way to handle events: callbacks. Instead of clunky listener interfaces or messy anonymous classes, SwtCallback enables one line solutions that make it easy to keep your event handling code in a single flat class – this while still being more readable and (surprisingly) improving encapsulation in some cases.

This latest release extends this functionality from just listeners to anything that takes a runnable. Prime examples in SWT are display.syncExec(), display.asyncExec() and timers.

For example, maybe you wish to refresh some UI components to reflect a change in data. But you’re not on the SWT thread so you have to use syncExec. Normally, you’d do something like,

display.syncExec(new Runnable() {
  public void run() {
    doUpdateSwtLabels();
  }
});

With a Callback you can turn this into one highly readable line:

display.syncExec(new Callback(this, "doUpdateSwtLabels"));

The most useful application may be for timers. In SWT, a timer needs to be reestablished at the end of timer execution if you wish it to recur. You may end up with unwieldy code such as,

void initWidgets() {
  /* ... */

  // Prime the timer.
  display.timerExec(INITIAL_DELAY, new Runnable() {
    public void run() {
      refresh();
    }
  }); 
}

void refresh() {
  /* ... update stuff ... */
  
  // Set the timer again.
  display.timerExec(TIMER_DELAY, new Runnable() {
    public void run() {
      refresh();
    }
  }); 
}

With a Callback you can now do this:

void initWidgets() {
  /* ... */

  // Prime the timer.
  display.timerExec(INITIAL_DELAY, 
    new Callback(this, "refresh")); 
}

void refresh() {
  /* ... update stuff ... */
  
  // Set the timer again.
  display.timerExec(TIMER_DELAY, 
    new Callback(this, "refresh")); 
}

This is much easier to read and follow, at least in my personal opinion. If you agree, go ahead and grab the download below – SwtCallback is released under the BSD license so you should be able to integrate it with whatever you’re working on.

Download the source and binary here:

Download SwtCallBack. More information is available here.

There’s some extra javadoc in this release to make it easier to get started. Still, there isn’t much in the way of documentation – we’ll go back and write some if there’s demand for it.

           

Today WireLoad is releasing SwtCallback, a Java library for SWT that enables callbacks for event handling. SwtCallback is inspired by the Swing enhancer Buoy by Peter Eastman.

If you know you want this, just skip to the bottom of this post for the download link. Otherwise, read on and I’ll explain the reason we wrote this library.

I’m a big fan of readable and concise code. Another thing I’m a big fan of is user interfaces that look and feel like what users expect. Given this, I’ve always had an aversion to UI programming in Java. Because I think it’s very telling, I’ll let this flash video illustrate: totally gridbag. Bottom line is that in Java, user interfaces look weird and often attempts to alleviate this weirdness result in enormous amounts of hard to read code.

One solution is to use the Standard Widget Toolkit (SWT) instead. SWT enables easier UI building with resulting UIs that are both faster and look and feel better for the end user. What’s more, the code is more concise thanks to FormLayouts, sane widget sizing and the availability of standard functionality.

There’s one thing I think can be improved on though: readability. SWT code has a tendency to, like Swing, become littered with hundreds of listener classes, or worse, faceless listener implementations. For example, your code may look like this:

public class Demo implements SelectionListener {

...
   void initialize() { 
      Button myButton = new Button(shell, SWT.NONE);
      myButton.setText("Click Me"); 
      myButton.addSelectionListener(this);
   }
...

   public void widgetDefaultSelected(SelectionEvent e) {
      // I don't care about this event but I have to 
      // have a handler to satisfy the interface.
   }

   public void widgetSelected(SelectionEvent e) {
      // Do something
   }
}

Notice how the method named ‘widgetSelected’ has a very generic name: it has to since that’s the name it was given in the SelectionListener interface. Also, if there are many widgets that listen for selection events, then this single method has to handle all of them with a big if statement or some such. Not very readable. We also had to thumb on conciseness by adding one method which we didn’t even want: widgetDefaultSelected.

A better method is to associate the handler with only a single widget by using an inner class, and to use an adapter to avoid having to add a dummy method. This would typically look like this:

Button myButton = new Button(shell, SWT.NONE);
myButton.setText("Click Me"); 
myButton.addSelectionListener(new SelectionAdapter() {
   public void widgetSelected(SelectionEvent e) {
      // Do something
   }			
});

Much better. Less code, easier to read and it’s clear what ‘do something’ is associated with. But now we end up with a bunch of anonymous classes and deeply nested code. It’s still not perfect.

Enter SwtCallback. With SwtCallback, our final version of the program may look like so:

void initialize() { 
   Button myButton = new Button(shell, SWT.NONE);
   myButton.setText("Click Me"); 
   Callback.add(myButton, SWT.Selection, this, 
      "myButtonSelected");
}

/**
 * Called when myButton is selected.
 */
@SuppressWarnings("unused")
private void myButtonSelected() {
   // Do something
}

This has everything we wanted: it’s clear what the ‘myButtonSelected’ method does because it’s well named. There are no listeners to implement and no inner class bloat. The definition of myButton is short without being complicated or hard to understand. As an added bonus SwtCallback allowed us to make the event handler method private – this makes sense since the method is only relevant for the corresponding UI class.

UI programmers with experience outside of Swing will hopefully immediately recognize and appreciate the idea of callbacks. If you still need more reasons though, I’ll suggest a couple:

• Less code means fewer bugs and easier maintenance. Callbacks allow you to handle events without lots of extra classes or big if-else statements.
• You can link many events to the same handler. For example, maybe you have a ‘Quit’ button in a window. This button can have the same handler as the standard close event for the window.
• No need for dummy methods. Since you’re not implementing listener interfaces you don’t have to implement handlers for events you don’t care about.
• Natural names for methods. You’re not constrained to some standard name for an event handler. You can name your method ‘handlePasswordFieldGainedFocus’ if you want to.
• Private or protected event handlers. With interfaces your event handling methods have to be public. Most of the time they’re very specific to some UI classes. It doesn’t make sense for other unrelated classes to call your handlePasswordFieldGainedFocus() method.

If you still need more, Peter Eastman, the author of Buoy, expresses the rationale for callbacks much better than I ever could here.

SwtCallback is released under the BSD license. Download the source and binary here:

Download SwtCallBack. More information is available here.

Patches and comments are welcome. Apologies for the lack of documentation – if there’s interest in this library we’ll revisit it. For now, if you find it useful, great!

Update 1: SwtCallback 0.2 has been released.