Våra medarbetares bloggar

2010-07-05

Magnus K Karlsson

Your First Cup of Coffee

A friend of mine asked me to provide a simple getting started guide for a first time Java programmer and it so happened it were other people that also wanted the same thing, so all of you out there here it comes, a simple learning by example guide in Java.

The example is a simple Web application that do simple Create, Retrieve, Update and Delete (CRUD) operation against a MySQL database.

Before starting writing you need to install the following on your system.

• Java 1.6 SE (http://java.sun.com/javase/downloads/index.jsp)
• MySQL Server and Query Browser (http://dev.mysql.com/downloads/)
• Maven2 (http://maven.apache.org/download.html)
• Eclipse EE 3.5.2 (http://eclipse.org/downloads/)

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-07-05

2010-07-03

Magnus K Karlsson

Getting Starting with Google Web Toolkit, GWT, Development

To get started first install appropriate plug-in for your IDE, in this article we will use Eclipse, but there are other great plug-in for other IDE as well.

Eclipse GWT plugin
http://code.google.com/eclipse/docs/download.html

One of the biggest difference between GWT 1.* and 2.* is the ability to debug and run your GWT application without the need to render/compile it. Now you can directly run/debug your GWT Java code without the time consuming compile step. But to do this you first need to install a plug-in to your web browser.

GWT Development Mode plugin for Firefox, IE and Safari
http://groups.google.com/group/google-web-toolkit/msg/51c5a09630ac61dc

After restarting Eclipse and your Web browser you are now ready to start developing. Begin with creating a new project and select Google → Web Application Project.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-07-03

2010-07-01

Magnus K Karlsson

Getting Started with Apache Camel and Prepare for Apache ServiceMix Deployment

Apache Camel is dream framework for any developers that is confronting with any type of integration task. What makes Apache Camel so great is:

• Testability. It is design from the beginning to be a framework that going to support Test Driven Development. With this follows a fast development cycle, since all code can be debugged and executed from a simple JUnit test case.
• Solves the two foremost problem that an integrator faces:
• Seamless protocol crossing, i.e. no coding for fetching data from e.g. HTTP and forwarding it to JMS.
• Default implementation of Enterprise Integration Pattern (http://www.eaipatterns.com/toc.html) that is easy to extend and configure. If you are not familiar with EIP, I recommend you to take the time and read the EIP homepage or if you do not want to miss a thing read the complete book written by Hophe and Woolf (http://www.amazon.com/Enterprise-Integration-Patterns-Designing-Deploying/dp/0321200683).

• Standalone Java Application
• Web Container
• J2EE Container

• Management. The ESB platform is specially design to manage integration programs.
• Redundancy and Scalability. A good ESB platform is specifically design to handle these issues when the load and uptime requirements increases.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-07-01

2010-06-28

Magnus K Karlsson

Problem Running Eclipse on Ubuntu 10.04 (Lucid Lynx)

I have been using Ubuntu for some time and it is really a great OS, but it is amazing why it is always Eclipse that brings the most headache when upgrading Ubuntu. For a couple a days ago I upgraded to Ubuntu 10.04, and everything works smoothly until I started Eclipse 3.5 SR1, with bug fixes I have previously described.

http://magnus-k-karlsson.blogspot.com/2009/11/problem-running-eclipse-in-ubuntu-910.html

This time the solution was to upgrade to Eclipse 3.5 SR 2 (Galileo), without the above bug fix. But thereafter m2eclipse gave me some problem, but now it seams to work after reinstalling m2eclipse and following the guideline in

http://m2eclipse.sonatype.org/installing-m2eclipse.html

“Note about 0.9.8 Workspace Incompatibility: If you are using m2eclipse 0.10.0 with a workspace that contains projects created under m2eclipse 0.9.8, you must remove the workspaceState.ser file. The workspaceState.ser file is located within the workspace directory in $workspacedir/.metadata/.plugins/org.maven.ide.eclipse/workspaceState.ser. If you remove this file, m2eclipse 0.10.0 will regenerate it as needed.”

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-06-28

2010-04-28

Divine Programmer

Slides from seminar on Dynamic Languages

ASTA 1982
Cobol 1982
Simula 1983-1984
CS4 1983
Lisp 1983-1990, 2000-2003 *
Logo 1983-1984 *
Prolog 1984-1985
Pascal 1985-1986 *
C 1985-1999 *
Scheme 1987-1988
Smalltalk 1985-1989, 2003-2010 *
HyperTalk/SuperTalk 1997-1991 *
Lingo 1990-1994, 1997 *
C++ 1993-1999, 2006-2008 *
PowerBuilder 1995-1996 *
Visual Basic 1996 *
Java 1995-2010 *
JavaScript 1995-1999, 2009-2010 *
ToonTalk 1999-2006
PHP 2001-2010 *
Erlang 2002, 2004, 2008
Oz 2003-2005
Python 2003-2010 *
Ruby 2005, 2008
(* = paid work)

Concurrent Comics
Magic Words

C
Lisp
Smalltalk
Python
JavaScript (CoffeScript)

Factor

Morph subclass: #Drawing
 instanceVariableNames: ''
 classVariableNames: ''
 poolDictionaries: ''
 category: 'MyClasses'

initialize
    super initialize.
    self color: Color white.
    self borderColor: Color black.
    self borderWidth: 2.
    self extent: 600@400.
    self position: 50@50.
    self clipSubmorphs: true.
    self on: #mouseDown send: #createCircle: to: self.

createCircle: event
    | circle |
    circle := EllipseMorph new.
    circle color: Color red.
    circle borderColor: Color black.
    circle borderWidth: 2.
    circle extent: 100@100.
    circle center: event position.
    self addMorphFront: circle.

To: self-interest@self.smli.com
Subject: Sun buys Java compiler technology based upon Self!!!
From: keith@uniteq.com (Keith Hankin)
Date: Tue, 18 Feb 1997 17:38:17 -0800

Sun has just announced that they are buying Animorphic Systems, which for the 
last 2+ years has been developing JIT compiler technology for Java and 
Smalltalk.  And, guess what?  It's based upon the Self project!!!
---
Source: http://www.merlintec.com/old-self-interest/msg01011.html

From: Dave Griswold <David.Griswold....@gmail.com>
Date: Tue, 2 Sep 2008 12:14:32 -0700 (PDT)
Local: Tues, Sep 2 2008 9:14 pm
Subject: Chrome and V8

Hi everyone,

It's been a while, but now that Google has announced Chrome and V8, I
can finally make a little clearer a major reason why I haven't been
pushing Strongtalk development for quite a while: Chrome's new
JavaScript engine V8.

The V8 development team has multiple members of the original
Animorphic team; it is headed by Lars Bak, who was the technical lead
for both Strongtalk and the HotSpot Java VM (as well as a huge
contributor to the original Self VM).   I think that you will find
that V8 has a lot of the creamy goodness of the Strongtalk and Self
VMs, with many big architectural improvements
---
Source: http://groups.google.com/group/strongtalk-general/browse_thread/thread/40eb8f405fbd3041/0abb010f0eac18e9

square
    ^self * self

function square(x) {
    return x * x;
}

square: (x) -> 
    x * x

public int square(int x) {
    return x * x;
}

self on: #mouseDown send: #createCircle: to: self.

button on: #mouseDown send: #value to: [Object inform: 'You clicked me'].

button.setOnClickListener(function (view) {
    view.setText("You Clicked Me!"); 
});

button.setOnClickListener((view) -> view.setText("You Clicked Me!"))

button.setOnClickListener(new View.OnClickListener() {
    public void onClick(View view) {
        (Button) view).setText(""You Clicked Me!")
    }
});

mood: greatly_improved if singing

if happy and knows_it
  claps_hands()
  cha_cha_cha()

date: if friday then sue else jill

expensive: or do_the_math()

var date, expensive, mood;
if (singing) {
  mood = greatly_improved;
}
if (happy && knows_it) {
  claps_hands();
  cha_cha_cha();
}

date = friday ? sue : jill;
expensive = expensive || do_the_math();

public static final synchronized 
List<Map<String, Product>> getProductList() {
    List<Map<String, Product>> productList = 
        new ArrayList<Map<String, Product>>();
    ...
}

def getProductList():
    productList = []
    ...

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-04-28

2010-04-18

Magnus K Karlsson

Administrating JBoss MBean From the Command Line Using twiddle

In production environment you usually monitor and administrate the JBoss Application Server through ssh and command line and this is adequate when starting, stopping and reading logs, but when you want to inspect, see status and change MBean values, the command line alternative is quite limited and since the MBean architecture is central in JBoss one really wants to use the JMX-console. The JMX-console is not the most user friendly tool, but has improved with JBoss 5 and the Web Console.

But there is an alternative if you want (or must) stick with the command line alternative – twiddle. The twiddle tool is not new and has been around since JBoss 4.3. And here follows a short walk through by examples.

To print out help information use:



Here you see the most imported commands: info, get, invoke and setattrs.

To get attribute and operation info:



To get attribute value:



To invoke an operation:

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-04-18

2010-04-15

Divine Programmer

RhinoDroid - JavaScript for Android

RhinoDroid is an experimental JavaScript app that runs on Android. The app contains a tiny HTTP server that accepts PUT requests with JavaScript as content. The app is based on the Mozilla Rhino Engine and the Android port by Brice Lambson.

Update: RhinoDroid is now called DroidScript. Get it at GitHub: http://github.com/divineprog/droidscript

Check ut the browser-based editor for DroidScript: http://droidscript.se

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-04-15

2010-04-06

Divine Programmer

Y Combinator explained

I have spent some time to look into the Y Combinator, a function for defining recursive functions without using conventional recursion support.

The Y Combinator is quite legendary in functional programming, and appears in "The Little Schemer", by Daniel P. Friedman and Matthias Felleisen. The idea is to show how recursion can be expressed in a language that does not support recursion (but has support for higher-order functions). As implementation language I will use JavaScript, and I will also show how Y can be expressed in Smalltalk and in Erlang.

A good article on Y written by James Coglan can be found here: http://blog.jcoglan.com/2008/01/10/deriving-the-y-combinator/. Like James Coglan, I write this blog article to better understand Y, and I use a somewhat different approach to explain it. A tool you can use to interactively experiment with the functions below, is this live browser-based JavaScript editor: http://droidscript.se/jsedit.html

Typically a recursive function is said to "call itself", like this recursive definition of the factorial function in JavaScript:

function factorial(n) {
    if (n == 0) { return 1; }
    else { return n * factorial(n - 1); }
}

factorial(3)

3 * (2 * (1 * (1)))

function repeat() {
    if (confirm("Continue?")) { repeat(); }
}

function twice(n) { return n * 2; }
alert(twice(22));

fun = function(n) { return n * 2 };
alert(fun(22));

result = (function(n) { return n * 2 }) (22);
alert(result);

(function(fun) { fun(fun); }) 
(function(fun) { 
    if (confirm("Continue?")) { fun(fun); });

repeat = (function(fun) { 
    if (confirm("Continue?")) { fun(fun); });
repeat(repeat);

factorial = (function(fun) { return fun(fun); })
    (function(fun) {
        return function(n) {
            return n == 0 ? 1 : n * fun(fun)(n - 1); } } );
alter(factorial(9));

Y = function(fun) {
    return (function(recurse) { return recurse(recurse); })
       (function(recurse) { return function(x) { 
           return fun(recurse(recurse))(x); }; });
};

factorial = function(recurse) {
    return function(n) {
        return n == 0 ? 1 : n * recurse(n - 1); } };
};

alert(Y(factorial)(9));

y := [:fun | [:recurse | recurse value: recurse] value:
    [:recurse | [:x | (fun value: 
        (recurse value: recurse)) value: x]]].

factorial := [:recurse | [:n | n = 0 
    ifTrue: [1] 
    ifFalse: [n * (recurse value: n - 1)]]].
   
(y value: factorial) value: 5000.

Y = fun(Function) -> 
    (fun(Recurse) -> Recurse(Recurse) end)
    (fun(Recurse) -> fun(X) -> 
        (Function(Recurse(Recurse)))(X) end end) end.

Y = fun(Function) -> 
    Go = fun(Recurse) -> fun(X) -> 
        (Function(Recurse(Recurse)))(X) end end,
    Go(Go) end.

Factorial = fun(Recurse) -> 
    fun(0) -> 1; 
       (N) -> N * Recurse(N - 1) end end.

(Y(Factorial))(5000).

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-04-06

2010-04-05

Divine Programmer

New version of DroidScript - JavaScript on Android

There is a new version of DroidScript available, see the DroidScript blog:
http://droidscript.blogspot.com/2010/04/version-4-of-droidscript.html

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-04-05

2010-04-05

Android development in Scheme - How to build Kawa for Android SDK 2.0

If you are into languages like Lisp and Scheme, you will appreciate Kawa, a Scheme implementation written in Java. Thanks to the work of Per Bothner, Kawa is available for Android.

The following is a how-to for installing Kawa for Android SDK 2.0 and getting started to write Scheme programs for Android. The how-to is based on a blog entry by Per Bothner. Note that you need to install Android SDK 2.0 before you proceed.

First build Kawa:

1) Go to the directory where you want Kawa to be installed. On my machine, this is:
cd /home/miki/android

Then download the sources from the Kava svn-repository with the command:
svn -q checkout svn://sourceware.org/svn/kawa/trunk kawa

2) Configure and build Kawa for Android. Go to the kawa directory and run configure, then make. You need to supply the location of the android.jar file in the Android 2.0 SDK. On my machine, the command sequence is:
cd /home/miki/android/kawa
./configure --with-android=/home/miki/android/android-sdk-linux/platforms/android-2.0/android.jar --disable-xquery
make

Next, create a Scheme project:

3) We will start by creating a standard Android Java project, and then modify it.
This is how you create a project template:

android create project \
--target 1 \
--name HelloScheme \
--path /home/miki/android/projects/HelloScheme \
--activity HelloScheme \
--package miki.helloscheme

4) Now, we will modify the project so that it can compile Scheme files. First of all, delete the generated Java source file (I'm using the full path in these examples, for clarity):
rm /home/miki/android/projects/HelloScheme/src/miki/helloscheme/HelloScheme.java

Copy the Kawa jar-file to your project's lib-folder (this is where external libs are stored; alternatively you can create a soft link to the kawa-1.9.90.jar):
cp /home/miki/android/kawa/kawa-1.9.90.jar /home/miki/android/projects/HelloScheme/libs/kawa.jar

Then replace /home/miki/android/projects/HelloScheme/build.xml with this customised version of build.xml.

The project is now configured to build Scheme programs.

Finally, write the Scheme version of Hello World:

5) Open a text editor and create the file: /home/miki/android/projects/HelloScheme/src/miki/helloscheme/HelloScheme.scm

Enter the following code into the file:

(module-extends android.app.Activity)
(module-name miki.helloscheme.HelloScheme)
(define (onCreate (savedInstanceState :: android.os.Bundle)) :: void
   (invoke-special android.app.Activity (this) 'onCreate savedInstanceState)
   (let ((textview :: android.widget.TextView (make android.widget.TextView (this))))
     (textview:setText "Hello, Android from Kawa Scheme!")
     ((this):setContentView textview)))

There is a more compact version of this program on Per Bothner's blog, but I didn't get it to work at the time of writing this.

Build and install on the emulator with:
ant install

Note that eval does not seem to be supported yet. Hopefully the ability to dynamically compile to Dalvik bytecode will be included into Kawa in the future.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-04-05

2010-03-26

Divine Programmer

Sikuli - Python source code with pictures

I love Sikuli! What I like most is that the source code contains pictures! Since I have a background in visual programming and programming languages based on comic strips, one might have guessed that I would fall for Sikuli :-) Even better, the programming language is Python (Jython), which makes for really clean code.

Now, what is Sikuli? It is a tool for scripting user interfaces, and it is based on matching images (for example an image of a button in the ui). I introduced Sikuli to a client the other day, and now they are using it to create automated ui tests for a web application.

I have one hint, importing modules with Python's standard import statement does not work, instead use execfile to load your Python modules (see link below).

Links:
http://groups.csail.mit.edu/uid/sikuli/
https://answers.launchpad.net/sikuli/+question/102003

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-03-26

2010-03-24

Divine Programmer

Talk on dynamic Android apps at SWDC2010

I will be giving a talk on dynamic languages on Android at the Scandinavian Web Developer Conference 2010. It goes without saying that I am proud of being invited to speak at this high-profile conference. I am looking forward to Marcus Ahnve talking about TDD and Android, and to Nikolai Onken's talk on accessing hardware from the browser, to name a few.

It is interesting to note that after years of having a trend towards browser based applications, the popularity of iPhone and Android has shifted focus back to "fat clients" in the form of mobile apps. Obviously, native apps have the potential for a richer user interface experience than what is possible with today's browser based apps.

But mobile apps tend to be a bit heavy going. In the case of iPhone, this is especially noteworthy. Not only is there a substantial development cycle (edit, compile, run) for native apps, Apple's notorious process for accepting apps to the app store stretches the deployment cycle to the magnitude of weeks.

Android development and deployment is quite smooth, thanks to the Eclipse plugin for Android, and to the fact that one can easily and legally deploy the app on any web site (you are not restricted to Android Market). Still there is some effort involved in deploying and installing new versions of an app. And the development process is still based on the build centric edit-compile-run cycle.

When it comes to web development, there is no need to rebuild and redeploy the application on every edit-run cycle. Thanks to JavaScript being a dynamic language, you can edit and reload only the part that has been updated. A web application is also trivial to deploy and upgrade (ahem, well in theory that is ;-).

In my talk at SWDC2010, I will discuss how dynamic languages like JavaScript can be used as a basis for a platform where applications can be deployed and updated with the same ease as for browser based applications. Furthermore, I will discuss how to take advantage of the dynamic nature of JavaScript for incremental development of applications, and demo the interactive editor in DroidScript, which is a simplistic but illustrative example of a Smalltalk inspired programming tool for Android.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-03-24

2010-03-23

Magnus K Karlsson

How To Remove Automatically Started Programs in Ubuntu 9.10 Karmic Koala

I while ago I blogged about how to setup Apache mod_proxy as a reverse proxy and I installed Tomcat and Apache Web Server with Synaptic Package Manager. The Synaptic Package Manager worked flawless  as usual, but it left me with one problem. The Tomcat Server did start automatically every time I booted Ubuntu, this is typically not wanted on a developer laptop, since you probably also are using some other Java Container that is default using port 8080.

Before we dive into how to remove the auto start in Ubuntu, lets first see how things are configured to be automatically started. As you know the start scripts are located in the



And to make programs autostart then there are soft links in the



There are several /etc/rc catalogs, and here follows the extract from one of mine catalog.



So one obvious option would be to directly delete all the soft links in these catalogs, but this is error prone and not recommended, but also it exists a tool to do exactly this – update-rc.d.



Now is Tomcat no longer automatically started when booting Ubuntu.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-03-23

2010-03-21

Divine Programmer

More DroidScript

I have written a couple of code examples that illustrate how to create ListViews in JavaScript on Android. See the DroidScript blog: http://droidscript.blogspot.com

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-03-21

2010-03-03

Divine Programmer

Google Closure

These are notes for a talk on Google Closure I will give tomorrow at GTUG Stockholm.

Note that Google Closure is a JavaScript library and toolkit, not to be confused with the Lisp dialect Clojure (which happens to be pronounced as "closure").

Overview
The Closure toolkit consists of the following parts:

• Closure Compiler - JS to JS compiler; optimises and checks your JavaScript code.
• Closure Library - very comprehensive; UI widgets, graphics, modules, packaging, DOM manipulation, communication, test framework, and much more.
• Closure Templates - dynamic generation of HTML using a template language; "small components that you compose to form your user interface"; for both client side (JavaScript) and server side (Java).
• Closure is used by large-scale web applications; it is the foundation for Gmail, Calendar, Docs, Blogger, and other Google products.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-03-03

2010-02-28

Magnus K Karlsson

Using JAX-WS in a Web Archive, as a Servlet, Running on JBoss 5.1

In my previous blog I showed how to get started with JAX-WS in a EJB archieve, in this blog I will show you how to do the same thing, but in a web archive instead, as a Servlet. If you think about it, the two different approaches ends with the same result – a Servlet that answer HTTP request with SOAP content.

 

 

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-02-28

2010-02-25

Magnus K Karlsson

How To See Expiration Date and other Information of a p12 File (PKCS12).

Sooner or later your client or server certificate will expire and it will be nice to update that before it really happens, but to do that you need to know how to get that information. In this blog I will show you how to do that in a Linux environment with openssl, that is a typical scenario when the certificate is located on a remote Linux server that you access with ssh.

First thing to do is to convert the p12 file (PKCS12 format) to X509 format, to do so we use the openssl command.



When prompted enter the password. Now is the content printed out, find out which CN (Common Name) that is for the server, typically it is the dns name of the server. After located the certificate then copy everything between the below start and end tag,



Past the copied content into a file with prefix .crt. If you were on a Windows system you could now simple double click the crt-file and the information of the certification would be display, but here we will continue using openssl. To use openssl, use the below command using the file name of the file you pasted the certificate into.



Now is the expiration date printed among other information.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-02-25

2010-02-21

Magnus K Karlsson

Configure Apache Web Server as Reverse Proxy in front of a Tomcat or J2EE Container

One production like scenario when using SSL or load balancing is to use a Apache Web Server in front of a Java Web Container or J2EE Container. There are two ways to make the Apache Web Server and the behind Java container – mod_proxy or mod_jk. In this blog I will show you how to use the mod_proxy alternative, acting as a reverse proxy. I will also use Ubuntu to show you how easy there is to install software on Ubuntu with Synaptic Package Manager.

The first thing to do is to install Apache Web Server and the Tomcat Container.



After installing the above software you can use the apache2ctl command to view the active sites configuration



or you can also list the files in /etc/apache2/sites-enabled



Before continue you can also check that everything is working by open a web browser and open http://localhost/ (Apache Web Server) and http://localhost:8080/ (Tomcat)

Now we go ahead and creating a new virtual host that is going to act as reverse proxy.





After creating the new site we need to link it from sites-enabled, either use ln -s or you can use the apache tool – a2ensite.



With the configuration in place, you need to separate the virtual host in customapp and default. For a locale environment you can separate them by using different IP – 127.0.0.1 and your computer IP.



The last thing before restarting the Apache Web Server is to install proxy and proxy_http modules you can do that with the Apache tool a2enmod



And finally you need to restart the Apache Web Server.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-02-21

2010-02-20

Divine Programmer

DroidScript - JavaScript for Android

I have published a post at my DroidScript blog that describes a tool for programming Android devices interactively in a web browser using JavaScript.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-02-20

2010-02-18

Magnus K Karlsson

Getting Started with JBoss Web Serivce using JAX-WS on JBoss 5.1 using Maven, OpenEJB and eviware soapUI

The easiest way to get started with writing Web Service is using Java API for XML Web Service, JAX-WS. The downside with this is that the creation of the WSDL file is automatic, and that is not the preferred way of writing cross platform independent web service. If that is your design goal, you should handwrite the WSDL, i.e. contract first. But if you know that the only clients are going to be Java client, than automatically generating the WSDL could be fine.

A good practice when writing all kind of code, is to make the code testable and also make it testable outside the container. To achieve that I will use OpenEJB, if have never heard or used OpenEJB and you are writing EJB 3.0 applications, it is definitely worth the time to check it out.

Lets start with writing a standard Stateless EJB.





src/main/resources/META-INF/ejb-jar.xml


src/main/resources/META-INF/jboss.xml


pom.xml


Now lets test our EJB with OpenEJB. The first thing we need to do, is to add the OpenEJB dependency to our pom.xml



Then we write our JUnit test case.



After verifying that our Stateless Session Bean is working, we now continue to deploy it to the JBoss container.



We start our JBoss container and checks that the EJB is successfully deployed.

Now lets add Web Service support to our EJB.





Now lets write our JUnit test case, to test our web service outside the JBoss container.



Before running the testcase we need to update our pom.xml with a concrete web service implementation.



After running the testcase from withing Eclipse, we can now be confident that we our is executing as expected. Now lets deploy our EJB to the JBoss container.



If you have stopped the JBoss, then restarted and verify that everything is looking healthy in the server log. Verify that the web service is working by firing up a web browser and go to http://localhost:8080/jbossws-example/HelloServiceBean?wsdl, to verify that you see the wsdl file.

Instead of writing a web service client, we are going to use a good test tool for testing web service – eviware soapUI. Start the soapUI and then select new project.

 

  

 

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-02-18

2010-02-17

Magnus K Karlsson

Viewing/Monitoring your Log4j Generated Log File with Chainsaw

Chainsaw is a open source tool for viewing and/or monitoring Log4j generating system. But the documentation on the homepage lack some explanation how to get started. To begin with maybe the simplest scenario, to view a log4j generated log file. The first thing one might misunderstand is that you need to defines a new configuration file for Chainsaw, so just pointing to your log4j.xm configuration file is not enough. Lets start with a example.



And the configuration file for Chainsaw.



Before we open Chainsaw lets write a small test program, that generates some log post, so we have something to view.



Now lets open Chainsaw. When first starting Chainsaw you are prompted to define a Receiver. Here we select our configuration file.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-02-17

2010-02-14

Magnus K Karlsson

Sending Log Errors with Log4j and SMTPAppender

Log4j comes with several Appenders and if you like to send mail notification if severe errors occur the you will be pleased to see, that Log4j comes with a SMTPAppender, but there are some pitfalls when using the SMTP appender:

• The SMTP apppender does not out of the box support a different SMTP port.
• Using secure connection, such as SSL or TLS.
• The derived standardized method setThreshold is ignored, and replaced with TriggeringEventEvaluator class.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-02-14

2010-02-11

Divine Programmer

Book Review: "Beginning Android"

Book Review: "Beginning Android"
Mark L. Murphy
Apress, 2009
ISBN: 978-1-4302-2419-8

I got a review copy of this book from Apress. Here is the review.

This is a book for programmers who have a basic knowledge of Java and want to get an introduction to the elements of Android programming. The book should be useful for both professionals and hobbyists. It is easy to read and well structured, and not too extensive, which makes it comprehensible. The 350 pages do a good job at covering a fair amount of the Android API. One area that is not covered is development tools, here the book refers to the Android web site (www.android.com). Setting up a development environment for Android can be tricky if you are new to programming, so this is an area where less experienced readers are left on their own.

The book covers Android 1.5, which is an old version by now. I however found the text and the code examples useful also for Android 2.1 development. The back inside cover mentions that there is a companion eBook available. An updated eBook would be of great added value, but it should be provided for free to customers who have purchased the book, not at additional cost as seems to currently be the case.

The style of writing is clear and the text is easy to read. The book is structured into several short chapters, where each chapter covers an aspect of Android development and the related parts of the API. Each chapter begins with an introduction that explains the topics covered in the chapter. Then follows a complete, runnable, and often short and concise code example that illustrates the chapter topic. This makes the book useful as a cookbook.

One not-so-nice aspect of the text is the use of supposedly funny section titles. I find titles like “Mother, May I”, “Halt! Who Goes There?”, ”When IPC Attacks!”, and “Seeing Pestering in Action”, to be quite irritating and distracting. The subject is interesting on its own merits, and the silly section titles actually make it harder to find what you are looking for in the book. There may, however, be readers who will find the titles entertaining. Another less good aspect of the book is the code style used, with no blanks between the parts of an expression. The first chapters use the correctly spaced Java-code style, but the majority of the chapters do not, and this is bad since it can establish bad coding practices among readers (especially beginners).

It is quite common for programming books to list classes and methods in the APIs covered, something which I find superfluous since the most current API documentation is available online. This book does not provide API listings, which is positive because it makes the text more coherent and flowing. It also saves pages, and makes room for more code examples and explanatory texts, which are added values compared to the online API documentation, and a reason for buying a book.

For me, the major value of the book has been as a cookbook of code examples. The examples in the book are often short, clear, useful, and on the spot on what you want to do.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-02-11

2010-02-01

Magnus K Karlsson

Java Generics Example Strategy Pattern

With Java Generics Java has continued its path to make it's language more strong typed, with comparison to all new dynamic language where they have thrown out strong typing. But Java Generics can also be hard to understand and one of the best example to show the main benefit with it is the strategy pattern. Lets start to look of a example.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-02-01

2010-01-30

Magnus K Karlsson

Maven Reporting with Cobertura, Dashboard, Change Report, FindBugs and PMD

I have been using maven coberture plugin before but it has one unimplemented function, aggregate cobertura report from multiple module. This can be solved by sonar and dashboard maven plugin, but Sonar requires that is run on a server, i.e. that you have a continuous integration server, but in some cases you have not got there and still is building your application locally than you can use the maven Dashboard plugin.


The parent pom.xml




The jar module pom.xml

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2010-01-30

2010-01-19

Divine Programmer

Twitter and refactoring (totally unrelated!)

I am now on Twitter @divineprog - but don't expect frequent updates, I am not the Twitter type really ;-) But perhaps I will grow fond of it once I learn how to use the Twitter infrastructure.

A couple of days ago, when renaming a bunch of methods in Eclipse using the refactoring function, it struck me, why not make changing the name of something do an automatic refactoring by default? It seems reasoable that if I change the name of en existing object, I would like everyone using the name of that object to update their references, right? It would make sense to ditch source text files and go all the way and manage the source code in an presistent in-memory database (I guess Eclipse maintains some kind of database-like view of the source code). Smalltalk has of course had this since the 70:ies ;-)

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2010-01-19

2009-12-29

Divine Programmer

Interactive development with Clojure

Here is a very nice video demo that illustrates interactive servlet development with Clojure. Same thing could be done on Android using the techniques referred to in the previous post.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-12-29

2009-12-29

Clojure REPL on Android

Found this thread where George Jahad explains how he implemented dynamic evaluation of Clojure on Android. Very cool how he dexed the dexer!

Interactive development and experimentation using a Read-Eval-Print-Loop is a great feature of dynamic languages. Really nice to see that Clojure attracts attention, it would be sad if Lisp would be forgotten. Lisp is one of the most productive languages I have ever worked with, and actually the first programming languages I was paid to program in.

Speaking of REPL, the way you can evaluate text in any window in Smalltalk is truly cool - just select an expression and "doit". I take this feature so for granted that I forget that this is not widely known outside the Smalltalk community. It would be nice to see a programming environment on Android that supports such a style of development, and RhinoDroid is one step on the way. I am working on a web based development tool for interactive programming on Android using JavaScript, hope to have that up and running soon.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-12-29

2009-12-14

Magnus K Karlsson

How to handle XML Schema Version?

Use the Schema verison attribute.
Pros:

• Simple

• No XML Schema enforcement when stepping version and version number is concealed for user.

• Do no use.

• Good för maintaining backward compability. No depending XML files needs to be altered, simply upgrade implementing jar.

• Cannot tell from the XML file which implementing jar version is used.

• Use this technique to handle minor version upgrade.

• Forces the user to upgrade the client code, when stepping version. Hard versioning control, no chanse to make misstake.

• No seamless upgrade. Upgrade will cost.

• Use this when stepping major version.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-12-14

2009-12-14

XML Schema Design Pattern - Handling Versioning and Reuse

In my last project I have been working with service orientated integration and ESB, in such an architecture the domain model is represented with a canonical model of a XML schema. There several way you can design your schema which I will describe bellow, but what is more imported is the implication it has on:

• Level of possibility to reuse your canonical model in different service.
• Level of possibility to handle different version of same service.
• Level of possibility to split your canonical data model into bit of pieces and process them in parallel.

• One root element, good for encapsulation.
• All elements are local and encapsulated.

• No reuse of elements.
• Easier to get started with.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
     targetNamespace="http://ns.msc.se/examples/book-russiandoll/v1_0_0"
     xmlns:russ="http://ns.msc.se/examples/book-russiandoll/v1_0_0" 
     elementFormDefault="qualified">
 
 <xs:element name="book">
  <xs:complexType>
   <xs:sequence>
    <xs:element name="Title" type="xs:string" />
    <xs:choice>
     <xs:element name="AuthorList" minOccurs="0" maxOccurs="unbounded">
      <xs:complexType>
       <xs:sequence>
        <xs:element name="Author">
         <xs:complexType>
          <xs:sequence>
           <xs:element name="givenName" type="xs:string" />
          </xs:sequence>
         </xs:complexType> 
        </xs:element>
       </xs:sequence>
      </xs:complexType>
     </xs:element>
    </xs:choice>
   </xs:sequence>
  </xs:complexType>
 </xs:element> 
 
</xs:schema>

• Many root elements, the XML file can be sliced into numerous ways.
• All elements are global, which allows reuse in other Schemas.

• Does not encapsulate and hide the schema.
• Usage of namespaces are almost a most, which makes usage more complex.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
     targetNamespace="http://ns.msc.se/examples/book-salamislice/v1_0_0"
     xmlns:salv1_0_0="http://ns.msc.se/examples/book-salamislice/v1_0_0" 
     elementFormDefault="qualified">

 <xs:element name="book">
  <xs:complexType>
   <xs:sequence>
    <xs:element ref="salv1_0_0:Title" />
    <xs:element ref="salv1_0_0:AuthorList" />
   </xs:sequence>
  </xs:complexType>
 </xs:element>

 <xs:element name="Title" type="xs:string" />

 <xs:element name="AuthorList">
  <xs:complexType>
   <xs:sequence>
    <xs:element ref="salv1_0_0:Author" minOccurs="0" maxOccurs="unbounded" />
   </xs:sequence>
  </xs:complexType>
 </xs:element>

 <xs:element name="Author">
  <xs:complexType>
   <xs:sequence>
    <xs:element ref="salv1_0_0:GivenName" />
    <xs:element ref="salv1_0_0:Surname" />
   </xs:sequence>
  </xs:complexType>
 </xs:element>
 
 <xs:element name="GivenName" type="xs:string" />
 
 <xs:element name="Surname" type="xs:string" />
 
</xs:schema>

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
     targetNamespace="http://ns.msc.se/examples/book-salamislice/v1_0_1"
     xmlns:salv1_0_0="http://ns.msc.se/examples/book-salamislice/v1_0_0"
     xmlns:salv1_0_1="http://ns.msc.se/examples/book-salamislice/v1_0_1" 
     elementFormDefault="qualified">
 
 <xs:import namespace="http://ns.msc.se/examples/book-salamislice/v1_0_0" schemaLocation="Book-SalamiSlice-v1.0.0.xsd" />

 <xs:element name="book">
  <xs:complexType>
   <xs:sequence>
    <xs:element ref="salv1_0_1:Title" />
    <xs:element ref="salv1_0_1:Category" />
    <xs:element ref="salv1_0_0:AuthorList" />
   </xs:sequence>
  </xs:complexType>
 </xs:element>
 
 <xs:element name="Title">
  <xs:simpleType>
   <xs:restriction base="xs:string">
    <xs:minLength value="3" />
   </xs:restriction>
  </xs:simpleType>
 </xs:element>
 
 <xs:element name="Category" type="xs:string" />
 
</xs:schema>

• Only one root element, good for encapsulation.
• All element are global, which allows reuse in other Schemas.

• Usage of namespaces are almost a most, which makes usage more complex.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
     targetNamespace="http://ns.msc.se/examples/book-venetianblind/v1_0_0"
     xmlns:ven="http://ns.msc.se/examples/book-venetianblind/v1_0_0" 
     elementFormDefault="qualified">

 <xs:element name="Book">
  <xs:complexType>
   <xs:sequence>
    <xs:element name="Title" type="ven:TitleType" />
    <xs:element name="AuthorList" type="ven:AuthorListType" />
   </xs:sequence>
  </xs:complexType>
 </xs:element>
 
 <xs:simpleType name="TitleType">
  <xs:restriction base="xs:string">
  </xs:restriction>
 </xs:simpleType>

 <xs:complexType name="AuthorListType">
  <xs:sequence>
   <xs:element name="Author" type="ven:AuthorType" minOccurs="0" maxOccurs="unbounded" />
  </xs:sequence>
 </xs:complexType>
 
 <xs:complexType name="AuthorType">
  <xs:sequence>
   <xs:element name="GivenName" type="ven:GivenNameType" />
   <xs:element name="Surname" type="ven:SurnameType" />
  </xs:sequence>
 </xs:complexType>
 
 <xs:simpleType name="GivenNameType">
  <xs:restriction base="xs:string">
  </xs:restriction>
 </xs:simpleType>

 <xs:simpleType name="SurnameType">
  <xs:restriction base="xs:string">
  </xs:restriction>
 </xs:simpleType>
 
</xs:schema>

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
     targetNamespace="http://ns.msc.se/examples/book-venetianblind/v1_0_1"
     xmlns:ven1_0_0="http://ns.msc.se/examples/book-venetianblind/v1_0_0"
     xmlns:ven1_0_1="http://ns.msc.se/examples/book-venetianblind/v1_0_1" 
     elementFormDefault="qualified">

 <xs:import namespace="http://ns.msc.se/examples/book-venetianblind/v1_0_0" schemaLocation="Book-VenetianBlind-v1.0.0.xsd" />

 <xs:element name="Book">
  <xs:complexType>
   <xs:sequence>
    <xs:element name="Title" type="ven1_0_1:TitleType" nillable="true" />
    <xs:element name="Category" type="ven1_0_1:CategoryType" nillable="true" />
    <xs:element name="AuthorList" type="ven1_0_0:AuthorListType" />
   </xs:sequence>
  </xs:complexType>
 </xs:element>
 
 <xs:simpleType name="TitleType">
  <xs:restriction base="xs:string">
  </xs:restriction>
 </xs:simpleType>

 <xs:simpleType name="CategoryType">
  <xs:restriction base="xs:string">
   <xs:enumeration value="SPORT" />
   <xs:enumeration value="COOKING" />
   <xs:enumeration value="PROGRAMMING" />
  </xs:restriction>
 </xs:simpleType>
 
</xs:schema>

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-12-14

2009-12-09

Divine Programmer

Domain Specific Languages

Today, I made a presentation on Domain Specific Languages at the MSC Office in Stockholm. The slides are here: http://www.comikit.se/dsl/dsl_talk_20091209/DSLSlides.html Press S to enter slide show mode, use N for next slide and P for previous slide. Or just scroll the document!

The presentation is written in a Python Slide Show DSL I made for the presentation, here is the source for the slides: http://www.comikit.se/dsl/dsl_talk_20091209/DSLSlides.py

The source code for the DSL is here: http://www.comikit.se/dsl/dsl_talk_20091209/SlideShow.py

My next DSL-related project is an interactive Game Development DSL in JavaScript for Android.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-12-09

2009-11-30

Divine Programmer

Interactive JavaScript on Android

I now have working version of a remote JavaScript scripting app running on Android. The app runs a HTTP server that accepts incoming PUT requests with JavaScript code as content. The code is evaluated on the Android, and the result is sent back to the client. Also have a workspace in Squeak/Pharo that I use to evaluate JavaScript on the Android. It is kind of neat to be able to interactively create views, buttons and so on. Will demo this on the upcoming GTUG meeting in Stockholm on Thursday December 3.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-11-30

2009-11-21

Divine Programmer

JavaScript (Rhino) on Android

Finally I have found a great dynamic language for writing Android apps - Rhino, a JavaScript implementation in Java. Rhino can run in interpreted mode, which makes it suitable for running on Dalvik (since on-the-fly byte code generation on Dalvik isn't implemented by dynamic languages, yet).

I used the work by Brice Lambson as a starting point. He has created a version of Rhino for the Android Scripting Environment (ASE). With the new release of the ASE you can now write scripts using JavaScript.

Since I want to write applications for Android in a dynamic language, I decided to experiment with embedding Rhino in an Android app. I created a new Android Java project, grabbed the Rhino jar-file from the ASE web site and dropped it in the libs directory. By browsing the documentation at the Rhino web site, it was quite straightforward to write a working demo.

Here is the code:

package miki.jsapp;

import android.app.Activity;
import android.os.Bundle;

import org.mozilla.javascript.*;

public class JSApp extends Activity
{
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        doit(
             "var widgets = Packages.android.widget;\n" +
             "var view = new widgets.TextView(TheActivity);\n" +
             "TheActivity.setContentView(view);\n" +
             "var text = 'Hello Android!\\nThis is JavaScript in action!';\n" +
             "view.append(text);"
             );
    }
   
    void doit(String code)
    {
        // Create an execution environment.
        Context cx = Context.enter();

        // Turn compilation off.
        cx.setOptimizationLevel(-1);

        try
        {
            // Initialize a variable scope with bindnings for 
            // standard objects (Object, Function, etc.)
            Scriptable scope = cx.initStandardObjects();

            // Set a global variable that holds the activity instance.
            ScriptableObject.putProperty(
                scope, "TheActivity", Context.javaToJS(this, scope));

            // Evaluate the script.
            cx.evaluateString(scope, code, "doit:", 1, null);           
        }
        finally
        {
            Context.exit();
        }
    }   
}

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-11-21

2009-11-04

Divine Programmer

PyConcordion - Writing Concordion tests in Python

Concordion is an open source test framework that encourages writing tests in a specification driven style. A key aspect is that tests are integrated into the textual specification of the system. This makes it possible to write requirements and tests simultaneously, and from a maintainability point of view, it is a great advantage to have requirements and tests tightly integrated.

PyConcordion allows you to write tests in Python, rather than Java (a very nice feature from the perspective of this blog!).

Each PyConcordion test has two parts, and HTML-file and a Python file. Specifications and declarative definitions of the tests are written in HTML. The scripting parts of the test that connects to the system being tested and implements services for the declarative tests are written in Python. Note that the Python code can be written in a declarative DSL-driven fashion, see the discussion on this page. The principle is to write a specification of a scenario, rather than coding a test script.

To try out PyConcordion, I downloaded PyConcordion and made an example based on this tutorial.

The example defined a very simplictic bank account object, called Account. Here goes the HTML-part of the specification.

File: Account.html
<html xmlns:concordion="http://www.concordion.org/2007/concordion">
<body>

    <h1>Account</h1>
   
    <h2>Overview</h2>
   
    <p>The Account object supports the following operations:
        <ul>
            <li>Ask for the account balance</li>
            <li>Deposit an amount</li>
            <li>Withdraw an amount</li>
        </ul>
    </p>
   
    <h2>Examples</h2>
   
    <p>
        A new account object has a balance of
        <span concordion:assertEquals="getBalance()">0</span>.
    </p>
   
    <p>
        If I open a new account and deposit
        <span concordion:execute="deposit(#TEXT)">1200</span>,
        the balance is
        <span concordion:assertEquals="getBalance()">1200</span>.
    </p>
   
    <p>
        If I deposit another
        <span concordion:execute="deposit(#TEXT)">600</span>,
        the new balance is
        <span concordion:assertEquals="getBalance()">1800</span>.
    </p>
   
    <p>
        If I withdraw
        <span concordion:execute="withdraw(#TEXT)">100</span>,
        the balance is
        <span concordion:assertEquals="getBalance()">1700</span>.
    </p>
   
</body>
</html>

And here is the Python code that defined the Account class.

File: AccountTest.py
#! /usr/bin/python

class AccountTest:
   
    def __init__(self):
        self.balance = 0
       
    def getBalance(self):
        return str(self.balance)
       
    def deposit(self, amount):
        self.balance = self.balance + int(amount)
       
    def withdraw(self, amount):
        self.balance = self.balance - int(amount)

To run the test, go to the folder that contains these two files, and run the command:
concordion_folder_runner ./

There are straightforward instructions on the PyConcordion web site on how to install the system under Linux.

When writing Python methods, remember to use self rather than this, especially if you are new to Python, and come from languages like C++, C#, or Java rather than Python. (Actually you can name the self-parameter anything, as it is explictly declared, but the convention is to use self.)

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-11-04

2009-11-02

Magnus K Karlsson

Problem Running Eclipse in Ubuntu 9.10 Karmic Koala

After upgrading to Ubuntu 9.10, Eclipse started to behave strangely. Button seams to be non-responsive, so I googled for a solution and came up with this link.

http://www.norio.be/blog/2009/10/problems-eclipse-buttons-ubuntu-910

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-11-02

2009-11-01

Divine Programmer

How to install Android SDK 2.0

The following is the procedure I used to install the Android SDK 2.0. It applies to Mac OS X and Linux (in my case Ubuntu). Note that Java SDK 1.6 (1.5 should also work?) must to be installed, before installing the Android SDK.

First download the SDK (SDK = Software Development Kit):

1) Download the SDK for your platform at: http://developer.android.com/sdk/

2) Unzip the SDK and move it to the directory where you want it installed. On my Ubuntu machine, I installed it in my home folder:
/home/miki/android/android-sdk-linux/

3) Add the SDK tools directory to the path by adding the following line to .bashrc. On my machine, it is:
export PATH=${PATH}:/home/miki/android/android-sdk-linux/tools

Next download additional SDK components using the Android SDK and AVD Manager:

4) Open the terminal and start the Android SDK and AVD Manager with the command:
android

5) Now a window opens where you can configure the SDK and create virtual devices. I had to force the manager to use http: rather that https: by selecting "Force..." under Settings, to be able to download the SDK components.

6) Select and install SDK packages under Available Packages. I installed:

• SDK Platform Android 2.0, API 5, revision 1
• Google APIs by Google Inc., Android 2.0, API 5, revision 1

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-11-01

2009-10-31

Magnus K Karlsson

Effective Unit Testing EJB 3.0 with OpenEJB

In my latest project we used EJB 3.0 and Maven2. And as any good programmer I wanted to have good code quality, which means good unit test test coverage, but my expectation on how to achieve this in an efficient manner was quite low, since mine previous experience with EJB 2.1 did not include any good testing experience. Even if coding EJB 3.0 has been greatly simplified, the fact still remains that the enterprise bean has still to be deployed before it can be tested. Of course can one program such that the logic is in a POJO rather directly in the bean itself, but to really be sure it is working the enterprise bean has to be deployed in a container, to be testable. So I started looking at different Maven plugin such as, jboss-maven-plugin and cargo-maven2-plugin, but then came across OpenEJB, which is really the salvation if you are developing EJB 3.0 and want good testing possibility. OpenEJB enable unit testing of enterprise beans as any POJO class! Lets look at some examples.

public class UserServiceSLSBTest {
private static final String EXPECTED_USERNAME_1 = "fornamn.1.efternamn@domain.com";
private static final String EXPECTED_USERNAME_2 = "fornamn.2.efternamn@domain.com";
private static final String EXPECTED_USERNAME_3 = "fornamn.3.efternamn@domain.com";
private Context ctx;

@BeforeClass
public static void oneTimeSetUp() {
}

@AfterClass
public static void oneTimeTearDown() {
}

@Before
public void setUp() throws Exception {
Properties props = new Properties();
props.setProperty(Context.INITIAL_CONTEXT_FACTORY,
"org.apache.openejb.client.LocalInitialContextFactory");

props.put("blogUnmanaged", "new://Resource?type=DataSource");
props.put("blogUnmanaged.JtaManaged", "false");
props.put("blogUnmanaged.JdbcDriver", "com.mysql.jdbc.Driver");
props.put("blogUnmanaged.JdbcUrl", "jdbc:mysql://localhost:3306/blog");
props.put("blogUnmanaged.username", "root");
props.put("blogUnmanaged.password", "");
// TODO fix properties hibernate.hbm2ddl.auto=create-drop

ctx = new InitialContext(props);
}

@After
public void tearDown() {
}

private UserServiceLocal createUserService() throws Exception {
Object obj = ctx.lookup(UserServiceSLSB.class.getSimpleName() + "Local");

assertNotNull(obj);
assertTrue(obj instanceof UserServiceLocal);
return (UserServiceLocal) obj;
}

@Test
public void testCreateUser() throws Exception {
UserServiceLocal userService = createUserService();

User user = new User();
user.setUsername(EXPECTED_USERNAME_1);
user.setPassword(EXPECTED_USERNAME_1);
user.setRoles(Roles.ADMIN);

userService.storeUser(user);
}
}

@Stateless
public class UserServiceSLSB implements UserServiceLocal {
private static final Logger log = LoggerFactory.getLogger(UserServiceSLSB.class);
@PersistenceContext(name = "blog-ejb", unitName = "blog-ejb")
protected EntityManager em;
@Resource
private SessionContext context;

@Override
public User findUserByUsername(String username) {
log.info("findUserByUsername username='" + username + "'...");
Query q = em.createQuery("SELECT u from User as u where u.username=:username");
q.setParameter("username", username);
List list = q.getResultList();
return (list.size() > 0) ? (User) list.get(0) : null;
}

private void checkExistingUser(User user) throws DuplicateException {
User existingUser = findUserByUsername(user.getUsername());
if (existingUser != null)
throw new DuplicateException("Duplicate " + user);
}

@Override
public void storeUser(User user) throws CredentialException, DuplicateException {
log.info("storeUser " + user + "...");
checkExistingUser(user);
if (user.getUserId() == null)
em.persist(user);
else
em.merge(user);
}
}

@Local
public interface UserServiceLocal {

public User findUserByUsername(String username);

public void storeUser(User user) throws CredentialException, DuplicateException;
}

<dependency>
<groupId>org.apache.openejb</groupId>
<artifactId>openejb-core</artifactId>
<version>3.1.1</version>
<scope>test</scope>
</dependency>

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Installing Firefox 3.5 on Ubunut 9.04 – the Jaunty Jackalope

After several crashes with Firefox 3.0x I decided to install the new Firefox 3.5, since the new version is managed with Synaptic Package Manager everything went smoothly, but with one gotcha. Do not remove the old Firefox, otherwise will panel shortcut and menu item be removed and when clicking on html files will nothing happens. Instead do the following:

sudo apt-get install firefox-3.5 firefox-3.5-gnome-support

sudo rm /usr/bin/firefox
sudo ln -s /usr/bin/firefox-3.5 /usr/bin/firefox

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Bundle a Common Jar Into EJB Jar with Maven Plugin maven-ejb-plugin

Yesterday I had some problem with packing an EJB3 jar with Maven plugin maven-ejb-plugin. The problem seemed quite common. To bundle a common jar dependency into an EJB jar, but after reading the documentation for the maven-ejb-plugin at http://maven.apache.org/plugins/maven-ejb-plugin/, it seemed clear that the plugin lacked this capability. After several hour of failure I ran into a workaround . Instead of configure the maven-ejb-plugin I used the maven-dependency-plugin to copy the desired dependency jar into the target/classes directory and then configure maven-dependency-plugin to run before the package phase.

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-ejb-plugin</artifactId>
<configuration>
<generateClient>false</generateClient>
<ejbVersion>3.0</ejbVersion>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>process-classes</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<includeGroupIds>se.msc.development</includeGroupIds>
<includeArtifactIds>common</includeArtifactIds>
<outputDirectory>${project.build.outputDirectory}</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>

<archive>
<manifest>
<addclasspath>true</addclasspath>
</manifest>
<manifestfile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestfile>
</archive>

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Configure Log4J DailyRollingFileAppender with custom PatternLayout

For some time I haven been planning to learn the mystic configuration of the org.apache.log4j.PatternLayout for Log4j and finally I have taken the time to do so.

• c - The calling class name, if giving without precision is the fully qualified name returned.
• C - The fully qualified class name.
• d - The date of the logging request, can be formatted with java.text.SimpleDateFormat, i.e. %d{yyyy-MM-dd}
• F - The name of the calling File.
• l - The location information, same as %C%M(%F:%L). This can be slow.
• L - The calling class line number
• m - The logging message.
• M - The calling class method.
• n - The platform dependent line separator.
• p - The logging Level.
• r - The relative date in millisecond since application start.
• t - The invoking thread.
• [x|X] - the Message Diagnostic (MDC) information.

<dependency>

<groupId>org.slf4j</groupId>

<artifactId>slf4j-log4j12</artifactId>

<version>1.4.2</version>

</dependency>

[INFO] Scanning for projects...

[INFO] Searching repository for plugin with prefix: 'dependency'.

[INFO] ------------------------------------------------------------------------

[INFO] Building Log4J Test

[INFO]    task-segment: [dependency:tree]

[INFO] ------------------------------------------------------------------------

[INFO] [dependency:tree]

[INFO] se.msc.development:log4j-test:jar:1.0-SNAPSHOT

[INFO] +- org.slf4j:slf4j-log4j12:jar:1.4.2:compile

[INFO] |  +- org.slf4j:slf4j-api:jar:1.4.2:compile

[INFO] |  \- log4j:log4j:jar:1.2.13:compile

[INFO] +- javax.mail:mail:jar:1.4.1:compile

[INFO] |  \- javax.activation:activation:jar:1.1.1:compile

[INFO] \- junit:junit:jar:4.5:test

[INFO] ------------------------------------------------------------------------

[INFO] BUILD SUCCESSFUL

[INFO] ------------------------------------------------------------------------

[INFO] Total time: 4 seconds

[INFO] Finished at: Mon Aug 24 03:05:27 CEST 2009

[INFO] Final Memory: 12M/144M

[INFO] ------------------------------------------------------------------------

package se.msc.log4j;

import org.junit.Test;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Log4JTest {
//import org.slf4j.Logger;
//import org.slf4j.LoggerFactory;
private static final Logger log = LoggerFactory.getLogger(Log4JTest.class);

//import org.apache.log4j.Logger;
//private static final Logger log = Logger.getLogger(Log4JTest.class);

@Test
public void testFoo() throws Exception {
log.info("Info log message.");
log.error("Fatal log message.", new NullPointerException("Null pointer exceptopn."));
}

}

# configure the root logger
log4j.rootLogger=INFO, STDOUT, DAILY

# configure the console appender
log4j.appender.STDOUT=org.apache.log4j.ConsoleAppender
log4j.appender.STDOUT.Target=System.out
log4j.appender.STDOUT.layout=org.apache.log4j.PatternLayout
log4j.appender.STDOUT.layout.conversionPattern=%d{yyyy-MM-dd HH:mm:ss.SSS} [%p] %c:%L - %m%n

# configure the daily rolling file appender
log4j.appender.DAILY=org.apache.log4j.DailyRollingFileAppender
log4j.appender.DAILY.File=/tmp/log4j/log4jtest.log
log4j.appender.DAILY.DatePattern='.'yyyy-MM-dd
log4j.appender.DAILY.layout=org.apache.log4j.PatternLayout
log4j.appender.DAILY.layout.conversionPattern=%d{yyyy-MM-dd HH:mm:ss.SSS} [%p] %c:%L - %m%n

2009-08-24 03:00:47.775 [INFO] se.msc.log4j.Log4JTest:18 - Info log message.
2009-08-24 03:00:47.783 [ERROR] se.msc.log4j.Log4JTest:19 - Fatal log message.
java.lang.NullPointerException: Null pointer exceptopn.
at se.msc.log4j.Log4JTest.testFoo(Log4JTest.java:19)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:73)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)
at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:45)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)

log4j.appender.DAILY.DatePattern='.'yyyy-MM-dd-a

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Firefox 3.5 brakes Eclipse 3.4

In mine previous blog I was writing about how to install Firefox 3.5 on Ubuntu 9.04, but that also had some unwanted side effect - it broke the Eclipse 3.4 installation!! Read more about http://hello-world-2-0.blogspot.com/2009/08/firefox-upgrade-broke-eclipse.html.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Getting rid of notification “Network service discovery disabled” in Ubunut 9.04

After installing the latest Ubuntu I have haunted with the annoying notification “Network service discovery disabled. You current network has a .local domain, which is not recommended and incompatible with the Avahi network service discovery. The service has been disabled.”

First of all I have to google what Avahi is and found the following short summary here: https://help.ubuntu.com/community/HowToZeroconf

After that, I got rid of the notification message, by removing the below file and then starting the Avahi service, since some files where not properly auto-created during installation.

sudo rm /var/run/avahi-daemon/disabled-for-unicast-local
sudo /etc/ini.d/avahi-daemon start

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Presentation for "Integration solutions with agile framework and Enterprise Service Bus, ESB"

Here comes the presentation for the "Integration solutions with agile framework and Enterprise Service Bus, ESB" seminar I held for some time ago.

http://docs.google.com/fileview?id=0BxdWn5V3EudmY2U3MGYxNGMtMGE0NS00NzhiLTk2Y2QtMDI4OWI5YTA4YTlk&hl=en

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Presentation for "Efficient J2EE Development with JPA, EJB3, Wicket, Maven2 and JBoss 5"

For some ago I held a presentation for "Efficient J2EE Development with JPA, EJB3, Wicket, Maven2 and JBoss 5" and here comes the material:

http://docs.google.com/fileview?id=0BxdWn5V3EudmNmRiNGEyZGMtMDFjZC00Zjg4LWJiYWEtODJmNDE1MGI5OTM5&hl=en

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

How to Enable Code Completion and Syntax Control Against XML Schema with Eclipse

When I was writing Apache Camel configuration XML files, I was frustrated over that I had no code completion or XML syntax check against Apache Camel Schema, but of source is that doable in Eclipse. Simple download the Schema to your computer and then open Eclipe:

Window->Preferences->XML->XML Catalog

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Clearlook Theme for Ubuntu – Clearlooks OSX

In the beginning I found it quite hard to find new themes, that was compatible with the standard Ubuntu way to install theme, i.e. from System->Preferences->Appearance.

But yesterday I found a nice OSX look that is not so grey as Mac OSX, it is also packaged in the standard Ubuntu installation way.

http://www.gnome-look.org/content/show.php/ClearlooksOSX?content=69487

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

How to Install Swedish Dictionary and Thesaurus for Open Office Writer

If you have installed a English distribution of Ubuntu you have already Open Office installed, but with no Swedish dictionary or Thesaurus. Do this to install:

• Open Office Writer.
• Select Tools->Language->More Dictionaries Online...
• Download the two wanted files Dictionary and Thesaurus. Now you have to oxt-files on your computer.
• Select Tools->Extension Manager and click Add then select oxt-file.
• Restart Open Office and from Tools->Language->For All Text->More. In the window select installed language for selected document.

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Writing to Syslog with Log4J and Testing It on Ubuntu 9.04 Jaunty

The preferred way to log in Linux is to write to the Syslog. For you that comes from the Windows world, Syslog is the equivalent for the Windows NT Event Log. Before you can ran the example below you need to enable Syslog Facility LOCAL1 on Ubuntu. The Facility can be looked as a filter and if you are running multiple programs on the same server, you might want to consider to let each program write to different Facility LOCAL[0-7].

To enable Facility LOCAL1 on Ubuntu 9.04 you first need to edit /etc/syslog.conf

>sudo gedit /etc/syslog.conf &

local1.*   /var/log/local1.log

>sudo gedit /etc/default/syslogd &

SYSLOGD="-r"

>sudo /etc/init.d/sysklogd restart

# configure the root logger
log4j.rootLogger=INFO, STDOUT, DAILY, SYSLOG_LOCAL1

# configure Syslog facility LOCAL1 appender
log4j.appender.SYSLOG_LOCAL1=org.apache.log4j.net.SyslogAppender
log4j.appender.SYSLOG_LOCAL1.threshold=WARN
log4j.appender.SYSLOG_LOCAL1.syslogHost=localhost
log4j.appender.SYSLOG_LOCAL1.facility=LOCAL1
log4j.appender.SYSLOG_LOCAL1.facilityPrinting=false
log4j.appender.SYSLOG_LOCAL1.layout=org.apache.log4j.PatternLayout
log4j.appender.SYSLOG_LOCAL1.layout.conversionPattern=[%p] %c:%L - %m%n

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Maven2 Reference Literature

For some time the best book on Maven2 was “Better Builds with Maven” which can be downloaded from http://www.maestrodev.com/better-build-maven, but now there is finally a more updated book, “Maven: The Definitive Guide“. Which is available from

http://www.sonatype.com/books/maven-book/reference/public-book.html

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

The Promising Standardized JSR 303 Bean Validation and Example of Usage

For too long have the Java world lived without a standardized bean validation specification and soon will the final approval hopefully be approved (2 Nov 2009). What does this imply?

1. Better Domain Driven Design, by putting the shallow domain validation in the POJO where it belongs.
2. Hopefully we can finally get rid of Value Objects Pattern which is a dark heritage from the EJB 2.1 age and instead use domain POJO beans through out our architecture. There is of course exception to this rule, e.g. in service layer where the exposed model is totally different than the domain model or in a UI layer with heavy usage of line charts, there an OO model does not fit into a point orientation representation.

<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

<modelVersion>4.0.0</modelVersion>
<groupId>se.msc.examples</groupId>
<artifactId>validation-domain</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<name>Validation :: Domain</name>
<url>http://www.msc.se/examples/validation</url>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

<repositories>
<repository>
<id>repository.jboss.org</id>
<url>http://repository.jboss.org/maven2</url>
<releases>
<enabled>true</enabled>
</releases>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>

<dependencies>
<!-- common logging library -->
<!-- version is depended on hibernate-annotations v3.4.0.GA -->
<!--
http://repo1.maven.org/maven2/org/hibernate/hibernate-annotations/3.4.0.GA/hibernate-annotations-3.4.0.GA.pom
-->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.4.2</version>
</dependency>
<!-- sun bean validation api -->
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>1.0.0.GA</version>
</dependency>
<!-- hibernate bean validation impl -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
<version>4.0.0.GA</version>
</dependency>
<!-- test support -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.7</version>
<scope>test</scope>
</dependency>
</dependencies>

<build>
<defaultGoal>install</defaultGoal>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
</plugins>
</build>

</project>

package se.msc.examples.validation.domain;

import java.io.Serializable;

import javax.validation.constraints.NotNull;
import javax.validation.constraints.Pattern;
import javax.validation.constraints.Size;

public class Person implements Serializable {
private static final long serialVersionUID = 1L;
private Long personId;
private String firstName;
@NotNull
@Size(min=1)
private String surname;
@NotNull
@Pattern(regexp=".+@.+\\.[a-z]+")
private String mail;

public Long getPersonId() {
return personId;
}

protected void setPersonId(Long personId) {
this.personId = personId;
}

public String getFirstName() {
return firstName;
}

public void setFirstName(String firstName) {
this.firstName = firstName;
}

public String getSurname() {
return surname;
}

public void setSurname(String surname) {
this.surname = surname;
}

public String getMail() {
return mail;
}

public void setMail(String mail) {
this.mail = mail;
}

}

package se.msc.examples.validation.domain;

import static org.junit.Assert.*;

import java.util.Set;

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

public class PersonTest {
private Validator validator;
private Person person;

@BeforeClass
public static void oneTimeSetUp() throws Exception {  
}

@AfterClass
public static void oneTimeTearDown() throws Exception {
}

@Before
public void setUp() throws Exception {
validator = Validation.buildDefaultValidatorFactory().getValidator();
person = new Person();
person.setFirstName("Magnus K");
person.setSurname("Karlsson");
person.setMail("magnus.k.karlsson@domain.se");  
}

@After
public void tearDown() throws Exception {
}

private  void debugPrint(Set> violations) {
for (ConstraintViolation violation : violations) {
String propertyPath = violation.getPropertyPath().toString();
String message = violation.getMessage();
System.out.println("invalid value for: '" + propertyPath + "': " + message);
}  
}

@Test
public void testValidate_OK() throws Exception {
Set> violations = validator.validate(person);
assertTrue(violations.size() == 0);
debugPrint(violations);
}

@Test
public void testValidate_FAIL_MAIL() throws Exception {
person.setMail("magnus.k.karlsson@domain");
Set> violations = validator.validate(person);
assertTrue(violations.size() == 1);
debugPrint(violations);
}

@Test
public void testValidate_FAIL_SURNAME() throws Exception {
person.setSurname(null);
Set> violations1 = validator.validate(person);
assertTrue(violations1.size() == 1);
debugPrint(violations1);

person.setSurname("");
Set> violations2 = validator.validate(person);
assertTrue(violations2.size() == 1);
debugPrint(violations2);  
}

}

javax.validation.constraints.Null.message=must be null
javax.validation.constraints.NotNull.message=must not be null
javax.validation.constraints.AssertTrue.message=must be true
javax.validation.constraints.AssertFalse.message=must be false
javax.validation.constraints.Min.message=must be greater than or equal to {value}
javax.validation.constraints.Max.message=must be less than or equal to {value}
javax.validation.constraints.Size.message=size must be between {min} and {max}
javax.validation.constraints.Digits.message=numeric value out of bounds (<{integer} digits>.<{fraction} digits> expected)
javax.validation.constraints.Past.message=must be a past date
javax.validation.constraints.Future.message=must be a future date
javax.validation.constraints.Pattern.message=must match the following regular expression: {regexp}

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-31

Integrate JSR 303 Bean Validation And ApacheWicket

In my previous blog I was writing about the new promising standard JSR 303 Bean Validation. In this article I will write about JSR 303 Bean Validation and Apache Wicket. Let start with recapitulate the domain object Person and see how we used the Bean Validation annotation to annotate our property constraints.

package se.msc.examples.validation.domain;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Pattern;
import javax.validation.constraints.Size;

@Entity
public class Person implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long personId;
@NotNull
@Size(min = 1, max = 250)
@Column(length = 250)
private String givenName;
@NotNull
@Size(min = 1)
@Column(length = 250)
private String surname;
@NotNull
@Pattern(regexp = ".+@.+\\.[a-z]+")
@Column(length = 250)
private String mail;

public Long getPersonId() {
return personId;
}

protected void setPersonId(Long personId) {
this.personId = personId;
}

public String getGivenName() {
return givenName;
}

public void setGivenName(String givenName) {
this.givenName = givenName;
}

public String getSurname() {
return surname;
}

public void setSurname(String surname) {
this.surname = surname;
}

public String getMail() {
return mail;
}

public void setMail(String mail) {
this.mail = mail;
}

}

package se.msc.examples;

import org.apache.wicket.markup.html.form.Button;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.markup.html.form.TextField;
import org.apache.wicket.model.CompoundPropertyModel;
import org.apache.wicket.model.LoadableDetachableModel;

public class FormBuilder<T> extends Form<T> {
private static final long serialVersionUID = 1L;
public static final String SUBMIT = "submit";

public FormBuilder(final String id, final T modelObject) {
super(id, new CompoundPropertyModel<T>(new LoadableDetachableModel<T>(
modelObject) {
private static final long serialVersionUID = 1L;

protected T load() {
return modelObject;
}
}));
}

public void addTextField(final String propertyName) {
TextField<T> textField = new TextField<T>(propertyName);
textField.add(new BeanValidator<T>(getModelObject(), propertyName));
add(textField);
}

public void addSubmitButton(final FormButtonListener<T> listener) {
final FormBuilder<T> parent = this;
add(new Button(SUBMIT) {
private static final long serialVersionUID = 1L;

public void onSubmit() {
parent.execSubmit(listener);
}
});
}

public Form<T> create() {
return this;
}

public void execSubmit(final FormButtonListener<T> listener) {
listener.onSubmit(getModelObject());
}

}

package se.msc.examples;

import java.util.Set;

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;

import org.apache.log4j.Logger;
import org.apache.wicket.validation.INullAcceptingValidator;
import org.apache.wicket.validation.IValidatable;
import org.apache.wicket.validation.ValidationError;

public class BeanValidator<T> implements INullAcceptingValidator<T> {
private static final long serialVersionUID = 1L;
private static final Logger log = Logger.getLogger(BeanValidator.class);
private final Class<T> beanClass;
private final String propertyName;

@SuppressWarnings("unchecked")
public BeanValidator(final T beanObject, final String propertyName) {
this.beanClass = (Class<T>) beanObject.getClass();
this.propertyName = propertyName;
}

@Override
public void validate(IValidatable<T> validatable) {
log.info("validate... " + validatable.getValue());
ReflectionUtil<T> util = new ReflectionUtil<T>();
T beanObject = util.createInstance(beanClass);
util.setPropertyValue(beanObject, propertyName, validatable.getValue());
Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
Set<ConstraintViolation<T>> violations = validator.validateProperty(beanObject, propertyName);
for (ConstraintViolation<T> violation : violations) {
String propertyPath = violation.getPropertyPath().toString();
String message = violation.getMessage();
log.error("invalid value for: '" + propertyPath + "': " + message);

ValidationError validationError = new ValidationError();
validationError.setMessage(message);
validatable.error(validationError);
}  
}

@Override
public String toString() {
return "[BeanValidator beanObject='" + beanClass + "']";
}

}

package se.msc.examples;

import org.apache.log4j.Logger;
import org.apache.wicket.PageParameters;
import org.apache.wicket.markup.html.WebPage;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.markup.html.panel.FeedbackPanel;

import se.msc.examples.validation.domain.Person;

public class PersonEditPage extends WebPage implements FormButtonListener<Person> {
private static final long serialVersionUID = 1L;
private static final Logger log = Logger.getLogger(PersonEditPage.class);
protected static final String FEEDBACK_PANEL = "feedbackPanel";
protected static final String PERSON_FORM = "personForm";
protected static final String GIVEN_NAME = "givenName";

public PersonEditPage(final PageParameters parameters) {
log.info("PersonPage...");
add(new FeedbackPanel(FEEDBACK_PANEL));
add(createForm(new Person()));
}

private Form<Person> createForm(Person person) {
FormBuilder<Person> builder = new FormBuilder<Person>(PERSON_FORM, person);
builder.addTextField(GIVEN_NAME);
builder.addSubmitButton(this);
return builder.create();
}

@Override
public void onSubmit(Person modelObject) {
log.info("onSubmit " + modelObject);
info("Successfully created '" + modelObject.getGivenName() + "'.");
}

}

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:wicket="http://wicket.apache.org/dtds.data/wicket-xhtml1.4-strict.dtd"
xml:lang="en" lang="en">
<head>
<title>Person Edit Page</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>

<div id="feedbackPanel" wicket:id="feedbackPanel">Feedback Panel</div>
<form id="personForm" wicket:id="personForm">
<fieldset style="width: 30em">
<legend>Person Edit</legend>
<table border="1" style="width: 100%">
<tr>
<td align="right">Given Name:</td>
<td><input id="givenName" wicket:id="givenName" type="text" style="width: 98%" /></td>
</tr>
<tr>
<td colspan="2" align="right">
<button id="submit" wicket:id="submit" type="submit">Submit</button>
</td>
</tr>
</table>
</fieldset>
</form>

</body>
</html>

package se.msc.examples;



import junit.framework.TestCase;



import org.apache.wicket.markup.html.form.Form;

import org.apache.wicket.markup.html.panel.FeedbackPanel;

import org.apache.wicket.util.tester.FormTester;

import org.apache.wicket.util.tester.WicketTester;



public class PersonEditPageTest extends TestCase {

private WicketTester tester;



@Override

public void setUp() throws Exception {

tester = new WicketTester(new WicketApplication());

tester.startPage(PersonEditPage.class);

tester.assertRenderedPage(PersonEditPage.class);

}



public void testLayout() throws Exception {

tester.assertComponent(PersonEditPage.FEEDBACK_PANEL,

FeedbackPanel.class);

tester.assertComponent(PersonEditPage.PERSON_FORM, Form.class);

}



public void testCreate_OK() throws Exception {

FormTester form = tester.newFormTester(PersonEditPage.PERSON_FORM);

form.setValue(PersonEditPage.GIVEN_NAME, "Magnus");

form.submit(FormBuilder.SUBMIT);



tester.assertRenderedPage(PersonEditPage.class);

tester.assertNoErrorMessage();

}



public void testCreate_GIVENNAME_FAIL() throws Exception {

FormTester form = tester.newFormTester(PersonEditPage.PERSON_FORM);

form.setValue(PersonEditPage.GIVEN_NAME, "");

form.submit(FormBuilder.SUBMIT);



tester.assertRenderedPage(PersonEditPage.class);

tester.assertErrorMessages(new String[] { "Field givenName is required." });



form = tester.newFormTester(PersonEditPage.PERSON_FORM);

form.setValue(PersonEditPage.GIVEN_NAME, " ");

form.submit(FormBuilder.SUBMIT);



tester.assertRenderedPage(PersonEditPage.class);

tester.assertErrorMessages(new String[] { "Field givenName is required." });  

}

}

by Magnus K Karlsson (magnus.r.karlsson@gmail.com) at 2009-10-31

2009-10-30

Divine Programmer

Why Android will be a big hit

The more I research the Android market and look into Android technologies, the more convinced I am that Android will be the next major computing platform. I view the situation as somewhat similar to 1984, when we had Mac and PC. Mac was a work of art, but a bit closed, and PC was open but rough, and MS-DOS and Windows 1.0 were primitive.

Today we have iPhone, exclusive and masterfully designed, but closed in several ways (much more closed than the Mac ever was). And we have Android, open and available for everyone, with lots of new devices on the way, in different formats and price categories. The big difference compared to 1984 is that Android is not MS-DOS. It is the complete opposite; carefully designed, fun, and open source. People who speculate when Linux will take over the desktop may now have the answer - Android Linux will take over the mobile device market.

Android will be the platform of choice, because it is open for developers. The SDK is free, and serveral new languages and tools are on their way. Simple is a Basic for the Android, developed by Google. The languge seems similar to Visual Basic, and this of course sucks, but I can see the logic here. There are many many Visual Basic programmers, and attracting them to Android is a smart move. There will likely be lots of apps developed, both in-house development at companies and hobby projects. To hobbyists, publising an application on Android Market, might be less of a hazzle compared to hosting and providing support for a web app. Plus, some apps and games a better implemeted as native programs.

Languages like Python, Lua and Perl are running on the Android Scripting Environment. This is a very promising and exiting opportunity for developing mini-applications using small script hacks. There are lots of other efforts going on to port popular languages to Android. Kawa Scheme seems to be a nice choise if you (like me) are fond of the Lisp-family of languages. Scala is also available on Android (some people say Scala is the next big language on the Java platform). Here is a tutorial. Another interesting initiative is App Inventor, a visual programming language for Android developed in Kawa Scheme.

Best of all, my collegue Göran Krampe is looking into porting the Smalltalk dialect Squeak to Android ;-)

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-10-30

2009-10-21

Divine Programmer

My first Android project

I have stared to develop on the Android and my the first project is now on GitHub:
http://github.com/mikaelkindborg/ComiCard

This is the starting point of what might become something similar to HyperCard. It would be really cool to have an easy-to-use autoring tool on Android. I hope Squeak will be ported to Android, then MagicWords would be easy to port.

Meanwhile I experiment with making Java-programming more enjoyable by exploring the design of an internal DSL based on declarative functional Lisp-like style.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-10-21

2009-10-21

PhoneGap

Just found PhoneGap, a JavaScript library for programming Android and iPhone apps in JavaScript. Looks really cool! I'm working on a book about JavaScript game development for children and teenagers (and curious grown-ups!), and PhoneGap could be a good library to use for games on Android and iPhone.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-10-21

2009-10-21

Gwt Smalltalk and Clamato

Gwt Smalltalk runs in the web browser and interacts with the Google Wave protocol. It is a great thing that Smalltalk is avaliable in the browser! Clamato is another Smalltalk that runs in a web browser. And here is an article that discusses languages that compile to JavaScript.

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-10-21

2009-10-21

The Duct Tape Programmer

Just read this article from Joel Spolsky.

Memorable quote:
"Duct tape programmers don’t give a shit what you think about them. They stick to simple basic and easy to use tools and use the extra brainpower that these tools leave them to write more useful features for their customers."

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-10-21

2009-10-21

Scheme on Android

Using Kawa you can author Android apps in Scheme. This looks promising:

(require 'android-defs)
(activity hello
 (on-create-view
  (let ((view (android.widget.TextView (this))))
    (view:setText "Hello World!")
    view)))

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-10-21

2009-10-21

Ruby hash map arguments

Ruby is a language with divine qualities, and why the lucky stiff has shown that Ruby programming is a beatiful art.

In Ruby you can pass a hash map to a method using a simplified syntax. The cool GUI-framework Shoes is an example of how this programming technique can be used.

Plain parameter passing

def foo(a, b)
 puts a, b
end

foo(1, 2)

def foo(*args)
 puts args[0], args[1]
end

foo(1, 2)

def foo(a, b, *args)
 puts a, b, args[0], args[1]
end

foo(1, 2, 3, 4)

def foo(values)
 puts values[:a], values[:b]
end

foo(:a => 1, :b => 2)

def foo(a, b, values)
 puts a, b, values[:a], values[:b]
end

foo(1, 2,  :a => 1, :b => 2)

def foo(values, a, b)
 puts a, b, values[:a], values[:b]
end

def foo(values, a, b)
 puts a, b, values[:a], values[:b]
end

foo({:a => 1, :b => 2}, 1, 2)

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-10-21

2009-10-21

Tiny Erlang web server - parallel version

Here is a version of the tiny web server that spawns a new process for each request. This is where Erlang shines. Processes are very lightweight and efficient in Erlang.

% Filename: mserver3.erl
% Tiny webserver that restarts on error.
% Requests are processed in parallel.
% Author: mikael.kindborg@gmail.com
% Date: September 2008

-module(mserver3).
-export([start/0, stop/0, supervisor/0, start_server/0, server/1, process_client_request/2]).

% How to benchmark:
% apache benchmark ab -n 100 -c 10 http://1.1.1.84:4042/hello.html

start() ->
   spawn(?MODULE, supervisor, []).
  
supervisor() ->
   io:format("Starting server.~n"),
   Pid = spawn(?MODULE, start_server, []),
   link(Pid),
   process_flag(trap_exit, true),
   receive
       {'EXIT', Pid, normal} ->
           io:format("Server exited normally.~n");
       {'EXIT', Pid, stopped} ->
           io:format("Server stopped.~n");
       {'EXIT', Pid, Reason} ->
           io:format("Server exited with code: ~w~n", [Reason]),
           timer:sleep(1000),
           supervisor();
       stop ->
           io:format("Stoppning supervisor.~n");
       Unknown ->
           io:format("Supervisor got an unknown message: ~w~n", [Unknown]),
           supervisor()
   end.

start_server() ->
   {ok, ServerSocket} = gen_tcp:listen(
       4042, [binary, {packet, 0}, {active, false}, {reuseaddr, true}]),
   on_exit(
       self(),
       fun (Why) ->
           gen_tcp:close(ServerSocket),
           io:format("Exiting server, closing ServerSocket, Why = ~w~n", [Why])
       end),
   server(ServerSocket).

stop() ->
   ServerAddress = "localhost",
   {ok, Socket} = gen_tcp:connect(ServerAddress, 4042, [binary, {packet, 0}]),
   ok = gen_tcp:send(Socket, <<"stop">>),
   ok = gen_tcp:close(Socket).

server(ServerSocket) ->
   {ok, Socket} = gen_tcp:accept(ServerSocket),
   spawn(?MODULE, process_client_request, [Socket, self()]),
   server(ServerSocket).

process_client_request(Socket, ServerPid) ->
   on_exit(
       self(),
       fun (Why) ->
           gen_tcp:close(Socket)
           % io:format("Exiting client request process, closing Socket, Why = ~w~n", [Why])
       end),
   {ok, BinaryData} = gen_tcp:recv(Socket, 0),   
   case BinaryData of
       <<"stop">> ->
           exit(ServerPid, stopped),
           io:format("Server stopped~n"),
           ok;
       <<"GET /stop", _/binary>> ->
           ok = gen_tcp:send(Socket, http_reply("Server stopped")),
           exit(ServerPid, stopped),
           io:format("Server stopped~n"),
           ok;
       <<"GET /echo", _/binary>> ->
           ok = gen_tcp:send(
               Socket,
               http_reply(binary_to_list(BinaryData)));
       <<"GET /", Request/binary>> ->
           ok = gen_tcp:send(
               Socket,
               http_reply(
                   readfile(
                       parse_filename(Request))));
       _Unknown ->
           ok = gen_tcp:send(Socket, http_reply("Unknown request")),
           io:format("Unknown request, BinaryData = ~s~n", [BinaryData])
   end.

parse_filename(Request) ->
   RequestString = binary_to_list(Request),
   StopIndex = string:str(RequestString, " HTTP"),
   Filename = string:substr(RequestString, 1, StopIndex-1),
   Filename.
  
readfile(Filename) ->
       {ok, Binary} = file:read_file(Filename),
       binary_to_list(Binary).

http_reply(Data) ->
   DataLength = string:len(Data),
   list_to_binary(
       "HTTP/1.1 200 OK\r\n" ++
       "Date: " ++ mdate:date_now_string() ++ "\r\n" ++
       "Server: MServer/0.1\r\n" ++
       "Last-Modified: " ++ mdate:date_now_string() ++ "\r\n" ++
       % Accept-Ranges: bytes
       "Content-Length: " ++ integer_to_list(DataLength) ++ "\r\n" ++
       "Connection: close\r\n" ++
       "Content-Type: text/html; charset=UTF-8\r\n\r\n" ++
       Data).

% Create an exit handler, a process that traps exit messages
% from another process. This can be used for a try/catch style
% error handling between processes.   
on_exit(Pid, ExitFun) ->
   spawn(
       fun() ->
           process_flag(trap_exit, true),
           link(Pid),
           receive
               {'EXIT', Pid, Why} -> ExitFun(Why)
           end
       end
   ).

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-10-21

2009-10-21

Tiny Erlang web server - sequential version

This is a tiny web server written in Erlang. Requests are processed sequentially.

% Filename: mserver2.erl
% Tiny webserver that restarts on error.
% Requests are processed sequentially.
% Author: mikael.kindborg@gmail.com
% Date: September 2008

-module(mserver2).
-export([start/0, stop/0, supervisor/0, start_server/0, server/1]).

% How to benchmark:
% apache benchmark ab -n 100 -c 10 http://1.1.1.84:4042/hello.html

start() ->
   spawn(?MODULE, supervisor, []).
  
supervisor() ->
   io:format("Starting server.~n"),
   Pid = spawn(?MODULE, start_server, []),
   link(Pid),
   process_flag(trap_exit, true),
   receive
       {'EXIT', Pid, normal} ->
           io:format("Server exited normally.~n"),
           timer:sleep(1000);
       {'EXIT', Pid, Reason} ->
           io:format("Server exited with code: ~w~n", [Reason]),
           timer:sleep(1000),
           supervisor();
       stop ->
           io:format("Stoppning supervisor.~n");
       Unknown ->
           io:format("Supervisor got an unknown message: ~w~n", [Unknown]),
           supervisor()
   end.

start_server() ->
   {ok, ServerSocket} = gen_tcp:listen(
       4042, [binary, {packet, 0}, {active, false}, {reuseaddr, true}]),
   on_exit(
       self(),
       fun (Why) ->
           gen_tcp:close(ServerSocket),
           io:format("Exiting server, closing ServerSocket, Why = ~w~n", [Why])
       end),
   server(ServerSocket).

stop() ->
   ServerAddress = "localhost",
   {ok, Socket} = gen_tcp:connect(ServerAddress, 4042, [binary, {packet, 0}]),
   ok = gen_tcp:send(Socket, <<"stop">>),
   ok = gen_tcp:close(Socket).

server(ServerSocket) ->
   {ok, Socket} = gen_tcp:accept(ServerSocket),
   {ok, BinaryData} = gen_tcp:recv(Socket, 0),   
   case BinaryData of
       <<"stop">> ->
           ok = gen_tcp:close(Socket),
           io:format("Server stopped~n"),
           ok;
       <<"GET /stop", _/binary>> ->
           ok = gen_tcp:send(Socket, http_reply("Server stopped")),
           ok = gen_tcp:close(Socket),
           io:format("Server stopped~n"),
           ok;
       <<"GET /echo", _/binary>> ->
           ok = gen_tcp:send(
               Socket,
               http_reply(binary_to_list(BinaryData))),
           ok = gen_tcp:close(Socket),
           server(ServerSocket);
       <<"GET /", Request/binary>> ->
           ok = gen_tcp:send(
               Socket,
               http_reply(
                   readfile(
                       parse_filename(Request)))),
           ok = gen_tcp:close(Socket),
           server(ServerSocket);
       _Unknown ->
           ok = gen_tcp:send(Socket, http_reply("Unknown request")),
           ok = gen_tcp:close(Socket),
           io:format("BinaryData = ~s~n", [BinaryData]),
           server(ServerSocket)
   end.

parse_filename(Request) ->
   RequestString = binary_to_list(Request),
   StopIndex = string:str(RequestString, " HTTP"),
   Filename = string:substr(RequestString, 1, StopIndex-1),
   Filename.
  
readfile(Filename) ->
       {ok, Binary} = file:read_file(Filename),
       binary_to_list(Binary).

http_reply(Data) ->
   DataLength = string:len(Data),
   list_to_binary(
       "HTTP/1.1 200 OK\r\n" ++
       "Date: " ++ mdate:date_now_string() ++ "\r\n" ++
       "Server: MServer/0.1\r\n" ++
       "Last-Modified: " ++ mdate:date_now_string() ++ "\r\n" ++
       % Accept-Ranges: bytes
       "Content-Length: " ++ integer_to_list(DataLength) ++ "\r\n" ++
       "Connection: close\r\n" ++
       "Content-Type: text/html; charset=UTF-8\r\n\r\n" ++
       Data).

% Create an exit handler, a process that traps exit messages
% from another process. This can be used for a try/catch style
% error handling between processes.   
on_exit(Pid, ExitFun) ->
   spawn(
       fun() ->
           process_flag(trap_exit, true),
           link(Pid),
           receive
               {'EXIT', Pid, Why} -> ExitFun(Why)
           end
       end
   ).

by Mikael Kindborg (mikael.kindborg@gmail.com) at 2009-10-21

Last updated: 2010-07-31