Jazoon 2009, Day One

23. June, 2009

It’s late, so only a very short summary of today.

James Gosling gave a broad overview what is currently happening at Sun. Nice video but little meat. I asked about what happened to closures but I’m not sure whether I can repeat his answer here. My feeling is that, behind the scenes, there’s a lot of emotions and that’s bad. Oh well, maybe some will simply implement something reasonable in the OpenJDK. Otherwise, Closures are probably dead in Java which is a bit of a pity.

Dirk König showed a the most common use cases for Groovy in a Java project. Nothing really new for anyone who had been in contact with Groovy for nicely packaged and showed some cool stuff you can do with this mature language.

After that, Neal Ford explained how Design Patterns started to disappear. We didn’t really notice but things like Iterators or Adapters have become features of the language itself. In Java, you still have to query a container for an iterator, in Groovy, you just container.each { … do something with each item … }. Really nice talk, as usual.

Missed most of the next talk because I talked to Dirk König but if you’re using Maven or Ant as a build system, you should have a look at Gradle. It fixes most of the issues with Ant and some of the ones with Maven. Later that day, Hans Dockter (a Gradle developer) and I tossed a couple of ideas back and forth how the build could be improved. If any of these could be implemented, we’ll see a new way to build software.

At 15:00, Jason van Zyl told us what is happening in and around Maven. His talk was so full of information, it was impossible to follow the slides and him. Maven 3.0 is due early 2010 and it will solve a lot of the issues in M2. One of the most important features: You get hooks to run stuff before and after a lifecycle phase. Ever wanted to calculate a build number? Now you can.

M3 is based on SAT4J, just like Eclipse p2. Now, if you followed my blog, you know that I hate p2. p2 is a piece of banana software, delivered green, ripes at the customer. Which is a pity. p2 solved a lot of the issues with the old installer and it could solve all the other issues but apparently, there are forced behind the scenes which make this almost impossible. So when you meet Pascal Rapicault next time, don’t blame him for all the misery he has caused you. He has to solve a mission impossible and that only works in movies.

Later that evening, Thomas Mueller talked about Testing Zen. Nothing really new but I’ll probably have a look at H2 next week or so. It could replace my favorite in-memory Java database HSQLDB.

The closing session was by Neal Ford again. I wish I could create slides that were only a fraction as great as his. *sigh* Anyway, he drew a large arc from how technologies can become obsolete within a few years (as we all know), how good intentions pave the road to hell, about our responsibilities as software developers which go beyond what’s in our contract and predicting the future. Well, Terminator is probably not a good example but everyone knows it. Still, I find it troubling that the military is deploying thousands of automated drones for surveillance. You don’t? How would you feel about a robot equiped with a working machine gun that is programmed to automatically fire on any human that isn’t wearing an RFID tag? Samsung installed a couple of them along the northern border of South Korea two years ago. Skynet, here we come!

What they don’t teach you about software at school: Be Smart!, the last talk of the day, was disappointing. I’ll give Ivar that he had to compete against Neal but … The topic was okay and what he said was correct and all but the presentation could use some improvement. ‘Nuff said.

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Posted by digulla

Printing Big Stuff On Linux

22. June, 2009

During the weekend, I tried to print my family tree. It was pretty simple to generate with GenealogyJ but frankly, the family tree view sucks. I was constantly shifting my “root” node to be able to see the parts I was interested in, etc. And printing this sucks even more. GJ will use lots of paper, printing huge empty boxes with lots of space around them. If I reduced the size of the parts which I don’t need, the layout fell apart. In short, I needed something better.

Graphviz to the rescue. A small Python program (100 lines) read the GED file and turned it into a graph with the layout of the persons just the way I wanted them to be. dot thought about the graph for a few seconds until it emitted a nice SVG which I could then print. Or so I thought.

I opened Inkscape and clicked on print. Yeah … that looks like the document … or rather a small part of it. Where is the poster print option? Ah, there is none. Great. Export as PNG with … oh … 150 DPI. Starting GIMP. No poster printing either. lpr tries to scale the image by .114537 which results in a 87 MB file. You gotta be kidding! kprinter? Nope … unless the command poster can be found.

A word of warning: The poster for openSUSE 11.1 (which you get with zypper) is broken. I tried it with both PostScript and Encapsulated PostScript and both resulting files were unusable in GhostView, GhostScript and Okular. Use this one instead.

After installing psutils, I could rotate the file to fit better on the page, too.

Conclusion: Most programs on Linux create PostScript files but printing them is still something for the command line. The recent print dialogs all look somewhat similar (but are different in tiny, annoying ways), each version is missing some important detail and most of them fail to simply print an oversized image on a single piece of paper or spread it over several. That Inkscape spits out an empty page after the document is just a minor issue.

What’s worse: The print preview either doesn’t work or doesn’t exist, printing to file is not implemented either or isn’t persistent. In the whole process, I ruined roughly 50 sheets of paper. *sigh*

In the end, I had a process which involved six different programs (GenealogyJ, Python, graphviz, Inkscape, pstops, poster) just for this standard task. Printing on Linux has some way to go, yet. On the positive side, I could script all these tasks and I could do it.

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Testing The Impossible: Inserting Into Database

5. June, 2009

Tests run slow when you need a database. An in-memory database like HSQLDB or Derby helps but at a cost: Your real database will accept some SQL which your test database won’t. So the question is: How can you write a performant test which uses the SQL of the real database?

My solution is to wrap the JDBC layer. Either use a mock JDBC interface like the one provided by mockrunner. Or write your own. With Java 5 and varargs, this is simple:

public int update (Connection conn, String sql, Object... params) throws SQLException {
    PreparedStatement stmt = null;
    try {
        stmt = conn.prepareStatement (sql);
        int i = 1;
        for (Object p: params) {
            stmt.setObject(i++, p);
        }
        return stmt.executeUpdate ();
    }
    finally {
        stmt.close ();
    }
}

Put all these methods into an object that you can pass around. In your tests, override this object with a mockup that simply collects the SQL strings and parameter arrays. You can even mix and match: By examining the SQL string, you can decide whether you want to run a query against the database or handle it internally.

This way, you can collect any newly created objects but still load some background data from the database (until you get bored and make the query methods return predefined results).

In the asserts, just collect all the results into a big String and compare them all at once.

Notes: The code above is a bit more complicated if you allow null values. In this case, you need to tell JDBC what the column type is. My solution is a NullParameter class which contains the type. If the loop encounters this class, then it calls setNull() instead of setObject().

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Posted by digulla

10K on StackOverflow

20. May, 2009

Just a little celebration that I finally reached 10K on SO 🙂

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Posted by digulla

Why New Technology is so Complicated

14. May, 2009

Ever wondered why the new cool thing is so complicated? There is a very good article which explains just that. In a nutshell: When the technology is invented, it’s invented by experts in the field. They have toyed with this idea for years, refined it, applied it in numerous projects and honed it until something new and useful came out.

Next come the early adoptors which are usually also experts in the field. They are always searching for a new, better solution and they are actively searching. The also have the background to understand what a new technology means for them, since they have the experience.

After that comes the normal user. The normal user has little idea what is going on, she just “wants to solve this simple problem.” The documentation (so far only written by experts for experts) mean little to her since she simply doesn’t have the background. She also doesn’t want to become an expert, this is usually going to be a single-strike project, so there is no intention to spend any time on learning the technology.

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Posted by digulla

env.js is Back

11. May, 2009

After quite some time of inactivity, env.js is back. There is a Google group and a git repository.

In case you’re wondering what env.js is: It emulates a web browser in pure JavaScript. What on earth could that be good for? This allows you to run your web application in a unit test. You can write your JavaScript, load env.js, your own code and then run it. You’ll have access to document, events, the DOM, everything. No browser bugs, yet, but that will probably come, too. With this gem, you can finally run your web app in a single process, with every bit of information readily available to your IDE’s debugger. No more messing with a remote or local web server, deploying your application and hoping that Tomcat could reload all classes, no more external browser process and guessing what might cause the odd behavior.

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Posted by digulla

Engineering SciFi

10. May, 2009

There are two types of people playing role playing games (RPGs), I call them the “story gamer” and  the “power gamer”. The story gamer likes a grand story while rules and dice rolls are a necessary evil. The power gamer enjoys the story but they relish in taking the rules to the limit. And they have their own definition of “limit”. While a story gamer likes to her “you switch on your personal force field and the bullets bounce off, sparking blue ripples that run over the surface of the field,” the power gamer asks “how does this screen work? Can I fry an eggs on it?”

In traditional SciFi, the inner workings of something are often a mystery. Space ships activate their force fields, protective screens, incoming fire gets deflected — or not, depending on what the author needs. But how do they work? Really? While this might sound like a silly question, it opens a whole new world: When you understand something, you can be creative with it. So how does a force field work? Can it be activated when something is blocking the space it will occupy in a moment? Is it a quantum effect or psionic? Magic? If it’s a personal shield, does it flow around the body or is it like a big bubble? If it’s a big bubble, how do you plan to charge through this door? If it can’t be activated when something is blocking it’s path, do you have to back away from any kind of cover to turn it on? Or if it can be activated, what happens when you lean against a wall? Are you stuck? Can you use the same effect to block a door, then? If nothing can pass through, how do your bullets get out? How about sound? Air?

Is the surface dull or slippery? If it’s slippery, how can you walk? If the field is guided through a mesh in the soles of your boots, how long does it take to rise after stumbling when you hands can’t get a hold? How do you plan to stand up when the enemy knows all this and tries anything to pin you down on the floor like a slippery fish? If it’s dull, what causes this? Is the field uneven? Is it static uneven or is there a ripple which sands off any surface you touch? Does it only stop solid matter? How about liquids? What happens when you’re pushed over a cliff? Get hit by a Molotow-cocktail? If the field stops bullets, how about light? If you can look out, can I blind you with a bright light? Cut you with a laser? If the laser is stopped, how can you see anything? And why is the field clear? Shouldn’t it be completely opaque in this case?

The answers to these questions tell us how a force field works and this gives us the basic blocks to build strategies. If the shield stops all matter, I must avoid lasers and heat weapons. And I need both an air supply and radio, so I can still talk to my team. If the air supply fails, that doesn’t render the screen unusable but I can only keep it up for a few seconds. Don’t forget that, in battle, you need much more oxygen than normal. If air can’t pass, I can use it as a space suit. It also means that the shield is rigid: It must create am opposing force to stop the matter trying to get through. So how can I move? How can the shield tell apart bending an arm from deflecting a baseball bat? Will it help when someone is bending my arm? How about being crushed under a tank? When something comes in, where does the energy go? In this universe, energy can’t be destroyed, it has to go somewhere. So when bullets come in, do I get pummeled? How is the shield projected? Can I put the projector in my pocket or do I have to wear a projector mesh that covers the whole body? Can this mesh have holes for your hands and head? Does that mean these parts are unprotected? That would allow to wear the shield as a flack vest. Or can I have projectors in the sleeves and around my neck which extend over my hands? Is the field perfectly clear or does it have a color? If there are holes, how about malfunction? Is there a chance to cut off my own head by switching it on? If the shield needs a lot of energy, how do I carry that along? How do I camouflage this? Or does a shield turn me into a beacon with a large sign “kill here”?

As you can see, all these questions have an impact on how I can use the shield during a game or in a story. It makes things more complicated, but it makes things more rich because I can start to work with these things. Story gamers expand the horizon but power gamers give it detail.

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Posted by digulla

Fighting Child Pr0n on the Net

8. May, 2009

Child abuse is something I keep an eye on and about which I have a strong opinion. In the last few weeks, German politicians discovered the topic. Foremost, our Minister for Family, Ursual von der Leyen, started a crusade to implement Internet filter technology at the ISP level to “fight” child pr0n. Note my subtle attempt to influence your opinion by using “crusade” which means to go to a foreign place, lay waste to the land, kill everyone there, in the name of all that is Good and Just.

Let’s see what the new law is trying to achieve. If you happen to click on a link that leads to a child pr0n site, you’ll see a stop page instead, explaining that you were about to see illegal content. While she insists that this will have no further consequences (especially, the time and IP will not be logged, the minister promised in a radio interview), there are already voices who want that data. Other voices already start crying “why don’t you block pirate sites, too?” We Germans know all too well how great censorship works, how easily it starts small, how fast it grows and what kind of persons it attracts. Not convinced? Let me give you some examples.

You’re browsing the web, follow an ad, and suddenly, you see the stop page. No harm done. Unless some clever guy at the ISP is making a private copy of the stop server’s log. And calls you the next day (since he can easily figure out who you are), threatening you to tell everyone about your disgusting character. Think about a moment how you would defend against such an attack. How would you explain to your wife/husband if it wasn’t you answering the phone?

Everyone knows how to secure a WLAN. Well, everyone, who knows more about WLAN other than how to buy one. So there are still many unprotected WLANs out there and guess who will go to jail after a criminal has used one of them to download lots of child pr0n. If it’s not a WLAN, then you’re better an expert in protecting your computer against viruses and remote control exploits. I mean, everyone is. There are no bot-nets out there, counting thousands of computers, where a criminal can do anything they damn well please, knowing full well that all the blame will go to the fool who owns the PC.

Or you’re like me and find child pr0n disgusting. Only, even downloading such an image is a criminal offense. So … when I would stumble upon something, I could not report that to the authorities because they would first arrest me, before considering going through to the tedious and probably futile process of trying to figure out who owns the domain where I found that stuff. If I would claim that a German domain contains child pr0n, the ISP would have to take down the site without being allowed to check whether my claims are true! If they did, the police would have to arrest them! Otherwise, the owner of the site could argue in court why he was being prosecuted and they were not. Before the law, all are equal, are they not?

To protect the people working at the German ISPs, the list of blocked sites must be secret. If that single sever is not working correctly (and how would you check that without going to jail?), this ISP is going to have a whole lot of very upset customers who suddenly see stop pages for legal sites. Or, the other way around, the server is not blocking something it should. How do you argue in court that a site which should have been on the list wasn’t blocked? It’s a secret list, you must not look at it!

So instead of spending money to create a help line for abused children, helping mothers and fathers to leave an abusive other, making the topic a non-taboo, so we could speak about it, politicians propose that we just don’t see the problem anymore. Sounds like a simple solution. We all know how good a simple solution sounds and how rarely they work out.

No criticism without a better proposal. If you don’t like thought-provoking ideas, this is not for you. Go away. Don’t read on. You’ve been warned.

All laws making temporary ownership of a small number of images must be revoked. Anyone on the planet must be allowed to report these findings without having to fear any kind of prosecution. No Internet censorship. Instead, we block access to domains which are run by registrars that boast not to comply to any law. That’s simple because we can block by IP (the list above would contain site names and as someone who knows what that means technically, that gives me nightmares). Anything left over must then come from a law-abiding registrar and those can and will take down such sites. Furthermore, they can quickly turn over the details about the person behind the offering, so they can be prosecuted like any other criminal. That doesn’t even need a lawyer or judge or court, anyone working for the ISP could check the site (because they won’t go to jail anymore), see what is going on and pull the plug within minutes. Before the police could hang up the phone, they’d have the name and address of the owner of the site and half an hour later, someone would have to answer some serious questions. And even if that person couldn’t be found, the site would be gone  forever, for anyone on the planet (instead of just for the 80 million Germans).

To find such sites, I’d turn to locked up, incurable offenders. Since they are incurable, they are effectively locked up forever. Why not use that as an advantage and, with their prior consent, give them a computer, a fat Internet connection and a well-loaded credit card? They could even locate material in closed user groups and fast-flux-networks, something a filter list will never be able to do. Everyone would get what they want. Cynical, but still true.

Radical? Maybe … but how would you call a “solution” which leaves the victims to suffer and the offenders free to cause more pain? Because that’s, in a nutshell, what the current proposal is all about. It’s probably a pure coincidence that such an important issue comes up close to the reelections.

Next time you see someone pointing and screaming at something, remember that they point at themselves with three fingers.

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Posted by digulla

Why aren’t IDEs intuitive?

8. May, 2009

Mark asked a simple question on stackoverflow.com:

This is stupid. Why can’t an IDE be intuitive enough that you can “good” at it immediately, and “great” after picking up a few shortcuts?

My answer is: Because computers aren’t powerful enough for this, today.

In the most simple case, the IDE would need several ways to layout the data on the screen, it would need several predefined keymaps with shortcuts (because different people do different work in the same IDE) and it would need a way to figure out who is using at right now to switch defaults. You would need to write two times the amount of code to implement all this because some thing are they way they are because the rest of the code is the way it is. IDEA can’t compile in the background, Eclipse can. To allow both ways of working, you would have to rewrite parts of the compiler API, the way the compiler talks to the UI, and in the IDEA case, you’d probably have to change the compiler itself.

Taking this one step further, the IDE would need to learn how the user works, what (s)he cares for, how (s)he thinks. The user is always resizing the console after starting the program? Let’s do it for her. It irritates the user that the IDE hangs for the fraction of a second when the IDE switches to the debug view? Let’s load the debug code in advance in the many spare seconds while we wait for anything to do.

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Posted by digulla

Trojan on ATMs

2. May, 2009

A few weeks ago, I stumbled over this: It appears that criminals have managed to install a Trojan on Russian ATMs. The Trojan would collect card data and pin numbers over the day and during the night, a “money mule” would collect a receipt with the numbers (which would look inconspicuous since a lot of people ask for a printout of their transaction). But this kind of attack is a new quality.

Home computers are administrated by … well … ignorants. People who want to use a computer, not understand it. For them, this box eats electricity and magically produces fancy graphics on the screen. They know how to email but they have no idea how mail works, they are oblivious to what actually happens when the computer sends an email. So it’s little wonder that most computers out there are infected with various kinds of viruses or Trojans and why “MAKE MONEY FAST” schemes still work so well.

The guys who build ATMs, on the other hand, are no ignorants. They ought to know exactly what they are doing and that someone can tap into the process is a new dimension. This is the difference between mugging innocent night owls and planned bank robbery. Computer crime has become as professional as the non-virtual counterpart. My guess is that we’ll need much more powerful computers in the near future which can store and access petabytes of data. Computers who can tell a legitimate operation from an illegal one and who can protect themselves against abuse. Computers who are powerful enough to watch every operation they are processing. Instead of only being able to crunch numbers, they need to understand what they do and how far reaching the consequences of an operation are.

It’s time for an immune system for computers. If we’re wiped out by Skynet in the not-so distant future, we’ll have to thank the mob.

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Posted by digulla

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