DDevelopment & Design

4Developers 2010 Review

I’ve been to 4Developers in 2009 in Cracow, together with Tomasz Przybysz and we had very nice impressions, no wonder then I wanted to signed up for 2010 edition in Poznań as well. Tomasz was sick, but Jakub Kurlenda decided to come with me. This time…I’ve been to 4Developers in 2009 in Cracow, together with Tomasz Przybysz and we had very nice impressions, no wonder then I wanted to signed up for 2010 edition in Poznań as well. Tomasz was sick, but Jakub Kurlenda decided to come with me. This time…

I’ve been to 4Developers in 2009 in Cracow, together with Tomasz Przybysz and we had very nice impressions, no wonder then I wanted to signed up for 2010 edition in Poznań as well. Tomasz was sick, but Jakub Kurlenda decided to come with me. This time our company was sponsoring the conference so I had a stand-up banner to carry.

Getting up at 4am is annoying, and you need to get up so early to get to Poznań by car. Thanks god it was  Friday, I could be dangerous if woken up at this hour on Saturday.

After arrival we were invited by high-heels hostesses. Now I’ll be a bit stereotypical programmer for a while: what on earth are so lovely hostesses doing on an IT conference? Yeah, sure they look nice, but hey, I thought I’m paying my money for the knowledge. If I wanted to go for good looking girls, I’d visit a local Salsa club. The best high-heels can do is distract me. And I’d rather you spend my bucks on better food, more speakers or just lower the price instead of this.

Unless, of course, these were local IT students helping for free. I strongly doubt if Poznań has so many female IT students all together in all its higher education facilities, but if that is the case, I’m starting to regret I’ve not moved to Poznań.

While I am at the organizational part, lets say that the rest was quite flawless, with tasty sandwiches, drinks, cookies and console games in between lectures. Two exceptions were: a bad lunch, served at Orbis Polonez hotel (and a total rip-off at 50zł) and no place to sit down while outside of conference rooms.

Not that we had any time, mind you. All the presentations had a tendency to take more than scheduled, and while it’s quite fine with me (it actually means there are people who’d rather listen than go for a cookie and coffee), the host didn’t seem to like it much. I think there should be more buffer time for breaks or maybe even an open space in between, to make everyone happy.

Fighting for live

Let’s get back to the lectures. The conference had four tracks, and I’ve started with ‘Fighting for live – derivatives and successors of Java are taking over the world’ by Michael Hunger. That was a big disappointment. Michael was way too theoretical. I’m afraid nothing from his speech would be useful to anyone in the room. And he didn’t give us much more than what we can actually find on wikipedia: just a brief list of some from 400+ languages running on JVM. The only interesting parts were actually played from youtube. I’ve not been waking up at 4am to watch youtube in Poznań. I can do it back home, you know.  As I said, a total disappointment.

Microsoft Cloud: Windows Azure

Angry and sad at the same time, I’ve decided to switch rooms to see Maarten Balliauw talking about Windows Azure. I’ve been thinking about using Google App Engine for my next project, so I wanted to know what Microsoft has to offer in terms of cloud computing. And boy, they do have stuff in there.

Maarten gave us a quick overview of a few projects surrounding the M$ cloud, and after that showed us how to move a simple ASP.NET application to Azure. Jakub Kurlenda, who I believe never had a chance to work with .NET, was amazed. It can't be that simple – he said – There's got to be a lot of problems with complex solutions. Well my friend, remember that M$ has inherited all the good stuff from Borland togethere with Anders Hejlsberg. Sure it sometimes doesn’t work perfectly, but still their tools are quite sexy. And way easier than anything you can find in Java world.

The Microsoft Azure does look very interesting. You get an MS SQL, Storage Service for unstructured data, front end web servers, back end servers and a AppFabric Service Bus to connect different services in a via-VPN-like manner. You even get an information marketplace Codename “Dallas”, to sell and buy services and data. Now this sound like an App Store of cloud computing, doesn’t it?

I think the war between cloud computing providers is going to be quite a show soon. And no matter whoever wins, I think that Microsoft won’t lose.

Not so Funky It Management

For the third lecture I’ve visited the IT Management track, where Peter Horsten, a guy who moved from Netherlands to Poland to create his company (Goyello) in Gdańsk, gave a speech about Funky It Management, but after half an hour I’ve returned to Java track uninspired. Peter is a great speaker, but for the first thirty minutes I heard nothing I could actually use or didn’t know already, so I wasn’t going to risk the rest of the time.

TopLink Grid and Oracle Coherence

That made me see only half of presentation from Waldemar Kot about TopLink Grid and Oracle Coherence, and I really regret that. Waldi, as he is sometimes called by friends (and notoriously by Jacek Laskowski) works for BEA… errr… Oracle, and while I do not know whether he is only consulting or also building systems for his clients, he is sharp as a Gillette, precise as a laser and full of knowledge. I really enjoyed his talk, there was a nice mix of theory and practice, and finally, some stuff I could actually use at work. Thanks Waldi.

Flex 4 and iPhone news

After a horrible lunch, Piotr Walczyszyn gave us a tutorial in using Flex 4. Years ago, I had a chance to use AMF to communicate between a heavy Flash frontend and a PHP backend, and it worked quite well. I have to note that especially debugging was nice, something I wouldn’t expect from a binary and proprietary format. For the last two years, I’ve been hearing about how easy it is to have a Java backend and Flex rich frontend. A lot of people I’ve met at the last year’s GeeCON conference actually worked that way. I was very interested in the topic and after the show I can tell you this, Flex is a way to go if you want to have a rich (heavy?) Intranet client. I think though, that its use for public/Internet services should be considered carefully. Too much bells and whistles and you are going down on frontend complexity and throughput. But you already know that, don’t you?

If using Java, I’d go for Flex 4 if Wicket is not rich enough for the solution. If Wicket is fine, I’d stay away from anything more complex (and difficult to test). I don’t have a lot of love for GWT, after what I’ve seen at work. But that could be a GXT fault, not a Google failure.

One of the most interesting news Piotr spread, was that Flex is being implemented on Android and… wait for it… iPhone! How’s that possible, you ask? We all know Apple doesn’t want to loose its AppStore market to on-line flash applications. Well, they are building a native Flex to Objective-C compiler, that’s how. If they manage to implement a runtime on Symbian and Windows Mobile, it may be the only truly portable technology. Unless you call HTML 5 a programming language, of course.

Java SE 7

After that Marcin Katas was talking about Java SE 7, which is scheduled for the end of this year. There was a lot about new Garbage Collector, that I don’t really care about, a few thing about OSGi-like solutions to dependency hell,  support for dynamic languages, new concurrency classes, closures and  Project Coin (small changes/additions to the language).

The only thing I can say is: why so late? And why so little?

Especially for Project Coin.  This is actually quite sad. Java as a language is being left behind its competitors. Really, Automatic Resource Management is a concept implemented YEARS ago with using in C#. Come on people, I’d at least expect stuff like .NET LINQ in new version of JDK, not even mentioning some long needed fixes for stuff like collections and generics. It’s been four long years since Java SE 6, there should be a Java SE 8 already.

I really think they should release a new version in a fixed interval of time, like Ubuntu is doing, like it was before Java SE 6. And forget about the hardcore backward compatibility, like with fu…-up generics. Banks that are still using J2SE 1.4 are not updating anyway.

Sobótka on Craftsmanship

And finally, I’ve been waiting for this one, Sławomir Sobótka, owner of Bottega, guy whose blog I’m actively reading, shared his thoughts about software craftsmanship.

That was by far the best presentation at the conference. Absolutely brilliant. I would not be able to put more meaningful information in such a short time and accessible way even had I tried for months. And to be honest, that was also the most important subject, useful to everyone, touching the work of every software developer in the room (and in the other .NET room as well). Kudos to you Sławek.

Too bad, there wasn’t anything new to me then. But maybe I should be actually glad, maybe it means I’m keeping up with the front line. Maybe, or maybe we are just reading the same books, groups and feeds (or I’m reading his blog actually). Anyway, I’m very happy about this lecture. What a beautiful world would it be if everyone was as passionate for craftsmanship and quality as  Sławek is.

I didn’t make it for OSGi speech from Jacek Laskowski. Sorry Jacek, but waking up at 4am doesn’t leave you a lot of strength for the last lecture. I’ve seen Jacek in action a few times, and it’s always a pleasure as he is a great showman (in a positive sense). I hope I’ll see you again at Warsaw’s JUG meetings, but now I’d rather get back to bed before midnight than get sick after the conference like all my friends did. Yeah, I’ve heard that Jakub Kurlenda got down just like Tomasz Przybysz a week ago, after the Winter Agile Tunning.

The price of knowledge has always been high, I guess.

Alltogether it was a very interesting conference and definitely worth the money.

Reviews (in Polish) from others can be seen here and here and here and here.

Solution Architect @ TouK

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DDevelopment & Design

How to automate tests with Groovy 2.0, Spock and Gradle

This is the launch of the 1st blog in my life, so cheers and have a nice reading!

y u no test?

Couple of years ago I wasn't a big fan of unit testing. It was obvious to me that well prepared unit tests are crucial though. I didn't known why exactly crucial yet then. I just felt they are important. My disliking to write automation tests was mostly related to the effort necessary to prepare them. Also a spaghetti code was easily spotted in test sources.

Some goodies at hand

Now I know! Test are crucial to get a better design and a confidence. Confidence to improve without a hesitation. Moreover, now I have the tool to make test automation easy as Sunday morning... I'm talking about the Spock Framework. If you got here probably already know what the Spock is, so I won't introduce it. Enough to say that Spock is an awesome unit testing tool which, thanks to Groovy AST Transformation, simplifies creation of tests greatly.

An obstacle

The point is, since a new major version of Groovy has been released (2.0), there is no matching version of Spock available yet.

What now?

Well, in a matter of fact there is such a version. It's still under development though. It can be obtained from this Maven repository. We can of course use the Maven to build a project and run tests. But why not to go even more "groovy" way? XML is not for humans, is it? Lets use Gradle.

The build file

Update: at the end of the post is updated version of the build file.
apply plugin: 'groovy'

apply plugin: 'idea'


def langLevel = 1.7


sourceCompatibility = langLevel

targetCompatibility = langLevel


group = 'com.tamashumi.example.testwithspock'

version = '0.1'


repositories {

    mavenLocal()

    mavenCentral()

    maven { url 'http://oss.sonatype.org/content/repositories/snapshots/' }

}


dependencies {

    groovy 'org.codehaus.groovy:groovy-all:2.0.1'

    testCompile 'org.spockframework:spock-core:0.7-groovy-2.0-SNAPSHOT'

}


idea {

    project {

        jdkName = langLevel

        languageLevel = langLevel

    }

}
As you can see the build.gradle file is almost self-explanatory. Groovy plugin is applied to compile groovy code. It needs groovy-all.jar - declared in version 2.0 at dependencies block just next to Spock in version 0.7. What's most important, mentioned Maven repository URL is added at repositories block.

Project structure and execution

Gradle's default project directory structure is similar to Maven's one. Unfortunately there is no 'create project' task and you have to create it by hand. It's not a big obstacle though. The structure you will create will more or less look as follows: 
<project root>

│

├── build.gradle

└── src

    ├── main

    │   ├── groovy

    └── test

        └── groovy
To build a project now you can type command gradle build or gradle test to only run tests.

How about Java?

You can test native Java code with Spock. Just add src/main/java directory and a following line to the build.gradle: 
apply plugin: 'java'
This way if you don't want or just can't deploy Groovy compiled stuff into your production JVM for any reason, still whole goodness of testing with Spock and Groovy is at your hand.

A silly-simple example

Just to show that it works, here you go with a basic example.

Java simple example class:

public class SimpleJavaClass {


    public int sumAll(int... args) {


        int sum = 0;


        for (int arg : args){

            sum += arg;

        }


        return sum;

    }

}

Groovy simple example class:

class SimpleGroovyClass {


    String concatenateAll(char separator, String... args) {


        args.join(separator as String)

    }

}

The test, uhm... I mean the Specification:

class JustASpecification extends Specification {


    @Unroll('Sums integers #integers into: #expectedResult')

    def "Can sum different amount of integers"() {


        given:

            def instance = new SimpleJavaClass()


        when:

            def result = instance.sumAll(* integers)


        then:

            result == expectedResult


        where:

            expectedResult | integers

            11             | [3, 3, 5]

            8              | [3, 5]

            254            | [2, 4, 8, 16, 32, 64, 128]

            22             | [7, 5, 6, 2, 2]

    }


    @Unroll('Concatenates strings #strings with separator "#separator" into: #expectedResult')

    def "Can concatenate different amount of integers with a specified separator"() {


        given:

            def instance = new SimpleGroovyClass()


        when:

            def result = instance.concatenateAll(separator, * strings)


        then:

            result == expectedResult


        where:

            expectedResult     | separator   | strings

            'Whasup dude?'     | ' ' as char | ['Whasup', 'dude?']

            '2012/09/15'       | '/' as char | ['2012', '09', '15']

            'nice-to-meet-you' | '-' as char | ['nice', 'to', 'meet', 'you']

    }

}
To run tests with Gradle simply execute command gradle test. Test reports can be found at <project root>/build/reports/tests/index.html and look kind a like this.


Please note that, thanks to @Unroll annotation, test is executed once per each parameters row in the 'table' at specification's where: block. This isn't a Java label, but a AST transformation magic.

IDE integration

Gradle's plugin for Iintellij Idea

I've added also Intellij Idea plugin for IDE project generation and some configuration for it (IDE's JDK name). To generate Idea's project files just run command: gradle idea There are available Eclipse and Netbeans plugins too, however I haven't tested them. Idea's one works well.

Intellij Idea's plugins for Gradle

Idea itself has a light Gradle support built-in on its own. To not get confused: Gradle has plugin for Idea and Idea has plugin for Gradle. To get even more 'pluginated', there is also JetGradle plugin within Idea. However I haven't found good reason for it's existence - well, maybe excluding one. It shows dependency tree. There is a bug though - JetGradle work's fine only for lang level 1.6. Strangely all the plugins together do not conflict each other. They even give complementary, quite useful tool set.

Running tests under IDE

Jest to add something sweet this is how Specification looks when run with jUnit  runner under Intellij Idea (right mouse button on JustASpecification class or whole folder of specification extending classes and select "Run ...". You'll see a nice view like this.

Building web application

If you need to build Java web application and bundle it as war archive just add plugin by typing the line 
apply plugin: 'war'
in the build.gradle file and create a directory src/main/webapp.

Want to know more?

If you haven't heard about Spock or Gradle before or just curious, check the following links:

What next?

The last thing left is to write the real production code you are about to test. No matter will it be Groovy or Java, I leave this to your need and invention. Of course, you are welcome to post a comments here. I'll answer or even write some more posts about the subject.

Important update

Spock version 0.7 has been released, so the above build file doesn't work anymore. It's easy to fix it though. Just remove last dash and a word SNAPSHOT from Spock dependency declaration. Other important thing is that now spock-core depends on groovy-all-2.0.5, so to avoid dependency conflict groovy dependency should be changed from version 2.0.1 to 2.0.5.
Besides oss.sonata.org snapshots maven repository can be removed. No obstacles any more and the build file now looks as follows: 
apply plugin: 'groovy'

apply plugin: 'idea'


def langLevel = 1.7


sourceCompatibility = langLevel

targetCompatibility = langLevel


group = 'com.tamashumi.example.testwithspock'

version = '0.1'


repositories {

    mavenLocal()

    mavenCentral()

}


dependencies {

    groovy 'org.codehaus.groovy:groovy-all:2.0.5'

    testCompile 'org.spockframework:spock-core:0.7-groovy-2.0'

}


idea {

    project {

        jdkName = langLevel

        languageLevel = langLevel

    }

}
DDevelopment & Design

Distributed scans with HBase

HBase is by design a columnar store, that is optimized for random reads. You just ask for a row using rowId as an identifier and you get your data instantaneously. Performing a scan on part or whole table is a completely different thing. First of all, it is sequential. Meaning it is rather slow, because it doesn't use all the RegionServers at the same time. It is implemented that way to realize the contract of Scan command - which has to return results sorted by key. So, how to do this efficiently?HBase is by design a columnar store, that is optimized for random reads. You just ask for a row using rowId as an identifier and you get your data instantaneously. Performing a scan on part or whole table is a completely different thing. First of all, it is sequential. Meaning it is rather slow, because it doesn't use all the RegionServers at the same time. It is implemented that way to realize the contract of Scan command - which has to return results sorted by key. So, how to do this efficiently?