Monthly Archives: March 2007

Online Books

As my list of pointers to free books has started to grow I decided to put it on my web site so I could easily point my friends to it. Here it is, in no particular order for the time being. I have several additional titles that are not within easy reach (the bookmarks, that is). Please do share if you gathered similar pointers.

If I was a stock broker I wouldn’t buy shares in any traditional (i.e., dead-tree) publishing house right now.

Software Engineering Radio Interview

At JAOO 2006 I gave an interview for Software Engineering Radio. Markus Voelter asked me questions about architecture evaluation, the topic of the talk I gave in the architecture quality track. Here are some of the questions that we covered:

  • Why would you perform an architecture evaluation?
  • When should you perform an architecture evaluation?
  • What are the prerequisites for evaluating an architecture?
  • How does architecture evaluation fit with agile development?

The interview is now available as a podcast; you can also download the slides from the Talks section of this site.I am surprised with the quality of the recording: the bartender was removing clean dishes from the dishwasher clese by. I don’t know how much post-processing was done but all that noise is not distracting. It was distracting while we recorded the interview so I’m glad that it doesn’t interfere with the conversation.

Don’t Miss this QCon Keynote: Democratizing The Cloud

If you’re going to next week’s QCon in London do yourself a favor and attend Erik Meijer’s keynote Democratizing The Cloud. Here’s Erik’s abstract:

The web is rocking the world of developers. Our customers love consistency. They want to have the same rich experience, anywhere, any time, on any device. Our sales people love market share. They want no platform that cannot leverage their web services. We ourselves have embraced agile methods. We want to keep our options open as long as possible and create software incrementally by successive refactorings. This surely sounds like a contradiction, another impossible triangle. As the Dutch artist MC Escher once said “Only those who attempt the absurd will achieve the impossible”. Hence we are trying to stretch the .NET framework to cover the Cloud such that it will become possible to incrementally and seamlessly design, develop, and debug complex distributed applications using your favorite existing and unmodified .NET compiler and deploy these applications anywhere.

Erik will show what consistency means; he will demonstrate how agilty translates into what you do right after you go to the File menu; he will prove how you can keep your options open until just about the very end. So if you’re only planning on attending a single QCon keynote, I strongly recommend Democratizing The Cloud. A few hours ago Erik, Jeff Van Gogh and myself reviewed the demos that he’ll show next week in London. You won’t believe me if I’d tell you, so better see for yourself. Do trust me though that they’re cool–I did work on the one involving validation. Hint: you’ll see p&p’s Enterprise LIbrary like you’ve never seen it before.

The Real Inversion of Control

A recent conversation with my friend and colleague Erik Meijer provided the nudge to finally write about something has been bothering me for some time. So here it goes…The popular view about Inversion of Control (IOC) is that it represents a technique for removing dependencies in object-oriented programs. People immediately think of their favorite dependency injection framework, whatever that may be. That’s nice and well, but is that the real IOC?Consider the following:

  • XML was pitched as a language specifically designed to make parsing easy so developers would not have to write another parser. That has happened allright, very few worry about parsing XML today. However while computers spend less cycles parsing well-formed markup, people crippled their languages with angle brackets, end tags, and a verbose syntax. This in spite the fact that the number of language users > number of XML parsers.
  • Good SOA design recommends building stateless services. Service implementations that follow these guidelines retain nothing from one invocation to another. However while the services do almost nothing to maintain the state of the service conversation, the developers building service consumers picked up the tab. Again, the number of service consumers > the number of services.
  • Web browsers allow people to interact with applications through widgets such as text boxes, radio buttons, check boxes, buttons, and a few more. These widgets are so primitive that they easily map into the native widgets provided by the virtually all contemporary host environments. However while the browser happily renders widgets with consipcuous text UI era traits, developers jumped through many hoops to push the user experience closer to what the platforms have been providing for years. And you guessed it, the number of web applications > the number of browsers.

There are other examples but I’ll stop at 3. The commonality across them is that in each case the software is simpler somewhere because many developers picked up the tab somewhere else. Instead of localizing complexity and putting the machines to work so we could enjoy other, more interesting challenges, the opposite happened. We now have to write in a verbose, ugly-looking language that the software can easily process; manage the state of service conversations so the servers would not bother about it; use plugins and pull lots of strings to give the user experience a face lift so the browsers do minimal processing and rendering; and so on. So consider this other way to look at IOC: the software is in control, and we’re working for it. Darn did I take the blue pill?