A few evenings ago I looked out of my kitchen window and saw an airplane’s vapor trail in the sunset - a beautiful, bright, clean, orange line cutting through the clouds. At that moment I had brief but unmistakable feeling of optimism about the human race.
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Google’s Protocol Buffers offer lightweight, language-independent object serialization. I love the design, especially as I’m increasingly seeing enterprise networks clogged with hordes of oversized XML messages. Protocol buffer bindings are available for C++, Java, and Python, but not C# yet. Once there is support for .NET, I think this could be a really interesting technology for financial applications.
When developing applications using Eclipse or a similar IDE, you quickly get used to being able to test your software immediately after making a change. Plugins like MyEclipseIDE enable that kind of instant edit/compile/test cycle for web applications as well.
But if you’re building web applications with Maven, it’s not so easy. Maven is a fantastic tool for building applications and managing dependencies, but it lends itself to a more batch-oriented mode of operation in which you build and deploy war files from the command line. I found myself wishing I could have the best of both worlds; building my web applications using Maven, but with a seamless edit/compile/test cycle when using Eclipse. Then I discovered the WTP (Web Tools Platform) project. Hallelujah!
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I ran across the following comments on an El Reg article about virtualization: Comments about “Virtualization: Nothing New”.
He’s right, isn’t he? Having the same company offer both virtualization and grid solutions is a truly virtuous pairing. First you tell people they need a grid solution to make a huge pool of computers look like a single one, then after it’s all set up you sell them virtualization software. It’s beautiful. It’s like if, for example, Nestle and Jenny Craig got together to simultaneously offer chocolate products and dieting solutions. Oh wait, they did: Nestle to buy Jenny Craig.
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My new favorite web hosting provider is A Small Orange. Their pricing is competitive, and their tech support is unbelievably quick and clueful.
Good article on Java5 Generics by Martin Wolf:
http://blogs.infosupport.com/martinw/articles/generics.aspx
It seems many programmers are confused about generics, in particular the use of the ? extends ... notation. The question mark is called a type wildcard, and is typically used as the value of a type parameter in a generic method. It means that wherever the method is invoked in your code, the compiler infers a specific type to be substituted for the wildcard and enforces that at compile time. The notation ? extends X is a bounded wildcard, meaning that the deduced type must be a subtype of X. Here’s a variation on Wolf’s example which I think might help clarify the difference.
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The US airline industry is a national embarrassment. I’m writing from Tampa, Florida where I just spent the night because of a flight delay which caused me to miss the last connecting flight of the day. I’ve flown about a dozen times in the last two years, and I can’t remember a single domestic flight that got me to my destination on time. The delays are always due to “weather” which means the airline has no obligation to compensate the passengers. How’s this for an idea? Any time a passenger is delayed more than four hours arriving at their ultimate destination when the entire trip is booked through a single airline, the passenger is entitled to a refund of 40% of the price of the flight, with an additional 10% penalty for every hour beyond that. If the flight is more than 10 hours late, the flight is free.
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This post continues my ongoing theme: That networks are great as long as software doesn’t pretend they are perfect. (I can’t take credit for the title - it’s been floating around for a long time.)
Increasingly, software is being designed based on the idea of treating network resources as local. The practice of generating proxy objects to invoke remote services increases the tendency to think this way, as does the success of HTTP based remote invocation patterns like REST, SOAP, etc. (It’s tempting to think of HTTP services like function calls: Send request with parameters, wait until results come back, proceed.)
But this is a bad idea. The concept of a network as a means of instantaneous communication between software components anywhere on the globe is an incorrect abstraction. Software should be designed based on the notion that networks are unreliable and introduce unpredictable amounts of latency into communication.
When you start a project to build a custom application for an enterprise customer, there are always universal requirements the customer doesn’t tell you about. These are things you have to do in order to implement the stated requirements, so I call them meta-requirements.
It’s helpful to keep a checklist of these and review them at the beginning of any new project, especially if the project is in an unfamiliar IT environment. Here’s my checklist of ten.
SOA - for Service Oriented Architecture - is the buzzword du jour. Organizations in all industries want to realize its promises, which include sharing information more openly and coherently across the enterprise and increasing organizational agility by making it easier to assemble new applications from existing components. Although there are fierce debates about the details (SOAP vs REST, contract first vs schema first vs code first, etc.) there is little disagreement about the general principles. Software should be constructed in the form of loosely coupled, coarse-grained, stateless services which can be invoked remotely over a network, and which form the basis of enterprise code reuse. This is a huge topic about which volumes have been written, but for now I’m going to focus on one issue: The importance of designing your SOA services to be resilient against network failures.
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