Welcome to my scratchpad

Eclipse Equinox ECF Unpack *pack.gz

2012-01-23T09:40:00.001+01:00

If you downloading Eclipse ECF as a ZIP file, the plugins folder in the ZIP contains pack200 compressed JAR files. The pack200 compressed files ends with *.pack.gz. The ECF ZIP distribution contains the same content like a normal Eclipse P2 update site.

If you like to use Eclipse Equinix ECF bundles without P2 or Eclipse you must unpack the pack200 OSGi bundels. For that eclipse provides a tool called "org.eclipse.equinox.p2.jarprocessor". Here a small bash script to show how to extract the OSGi bundles from the pack200 files.

Links

Eclipse Pack200 Documentation - http://wiki.eclipse.org/Pack200
Eclipse ECF Download Page - http://www.eclipse.org/ecf/downloads.php

Mockito the Java Standard Mocking Framework?

2011-12-10T13:46:00.001+01:00

I used a long time JMock and I really love it, I also used a lot EasyMock because of the answer and capture feature. About a year ago I found the mocking framework mockito. After that I was able to inspire a few work colleagues to use mockito in their projets. I play around with it again and my conclusion is: Mockito is at the moment the best mocking framework for Java and I'm not alone.

"We decided during the main conference that we should use JUnit 4 and Mockito because we think they are the future of TDD and mocking in Java" - Dan North, the originator of BDD

Mockito has a clean syntax and the patterns and ideas behind mockito make tests more maintainable. Mockito has the power of EasyMock but a smarter syntax. Today I build for my self a simple JUnit test as mockito cheat sheet. So you convince yourself with Mockito and the smart API see the demo test bellow.

Links

Mockito Project Site
http://code.google.com/p/mockito/
Documentation Mockito
http://docs.mockito.googlecode.com/hg/latest/org/mockito/Mockito.html
GitHub Project with the Cheat Sheet Test
https://github.com/tux2323/mockito-cheat-sheet

Test Doubles and Mocking Patterns

2011-11-23T09:49:00.001+01:00

Yesterday I refactored a unit test with over 2000 lines of code, now the test has around 900 lines of code. One pattern I found in the test was that for every kind of test double a mock object was used.

I prefer the following test design rule for mock objects and test doubles. Object which contains logic e.g. of type service, factory or repository should be mocked instead of DTOs, value objects or entities (plain Java Beans) with getters and setters e.g. configuration objects this kind of object should never be mocked.

Here small example, a test with to much mocking, please don't write such kind of tests:

This simple unit test above has to much mocking logic and should be refactored to this test:

If you like you could use the builder pattern for the simple objects like sale to get the test a little bit nicer (see the links for eclipse tooling). A smell is when you need to mock classes, in most cases then you should use another test double pattern for this kind of objects, or something with the design of the SUT is wrong.

What I like to say is you should not always use our preferred mocking framework to create a mock object as test double for everything. There are situations where mock object I believe are a test design anti pattern / smell. Think about stubs and dummy object before creating a mock object and read the great xUnit test pattern book “xUnit Test Patterns” from Gerard Meszaros. Then you are on the right way to get an agile tester ;-)

Links

xUnit Paterns - http://xunitpatterns.com/
Test Double - http://xunitpatterns.com/Test%20Double.html
Builder Eclipse Plugin - http://code.google.com/p/fluent-builders-generator-eclipse-plugin/

OSGi Users' Forum Germany Community Event 2011

2011-11-17T13:00:00.003+01:00

This year the OSGi UFG Event was based in Cologne. The event was great a lot of new input. My favorite topics were PojoSR and OBR (OSGi Bundle Repository). A great podiums discussion on OBR there was a great discussion about commercial bundle repositories "App Store for Bundles".

Richard Nicholson (OSGi Alliance President) could not make it to event, because he has an important meeting in UK . So we shortly changed the Keynote "OSGi Alliance Update" to "OSGi Community Update". In this session I tried to give an overview what happens in the OSGi World/Community in the year 2011. I believe I missed a lot of stuff, but when I prepared the session I become the feeling 2011 was a lot of work in OSGi Community done. I think OSGi was not much in the news but a lot of new open source projects and also a lot of progress in the OSGi specification was done. For example the enterprise specification was finished, the OSGi Core specification 4.3 was released in April, the package admin is now deprecated, we have now a much better API the Wire API. Also in the tooling area much happens in this year. I think BNDTools could become the standard tooling for OSGi. Hope Neil well release the BNDTools Version 1.0.0 this week ;-)

OSGi Community Update

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The first session on the UFG was about OSGI in Healthcare applications and smart cards. The talk covers the n-pad product which is used for the German "Gesundheitkarte". Stephan Hoffmann-Emden and Andreas Klotz shows in short live demo how there OSGi based smartcard reader works. They have built a PKI Service for their OSGi platform. Is there a standard for PKI / crypto handling in OSGi?

n-pat: Modulare Anwendungsplattform mit Smartcards

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In the next session Andreas Kraft cover the topic "OSGi in the Residential Market". Andreas gives a good overview which topics will be in the OSGi Residential specification. The talks give also a short introduction in the OSGi Alliance Processes e.g. what is an RFP and so on.

After a small coffee break Holger Hoffstätte gives a really nice overview on OBR. His statement the important thing about OBR is the model. I think OBR will fix a lot of problems in OSGi tooling and deployment. I think it will also play a rule in the SEITENBAU OSGi projects. OBR solves a lot of problems we have at SEITENBAU and we now have solved by custom solutions. So we need it right now.

Hilf mir, OBR - Du bist meine letzte Hoffnung!

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In the podiums discussion "OSGi Bundle Repository versus Apache Maven Repository" we have lot of good discussion. Okay the title was not perfect ;-).

First session in the second track after launch was PojoSR my favorite session. Karl Pauls explains why we need PojoSR and how to migrate Projects to OSGi by using PojoSR. He also covers very well the problems when migrating existing projects to OSGi. I think Pauls statement is absolute true PojoSR brings µServices to the rest of us.

PojoSR or OSGi (µ)Services For the Rest of Us

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Ralf Sternberg and Frank Appel shows with a great live demo how to use RAP with OSGi. They also explains how RAP application benefit by using OSGi. I didn’t know the actual RAP Version is based on OSGi services and do not use the eclipse plugin registry. I hope will have a little free time to try and play around with the actual RAP version. In the session Ralf and Frank shows also a RAP based smartphone client.

After the RAP session Stefan Kachel introduce the eclipse project Riena. Riena makes the SWT UI development much easier. There is also an eclipse toolbox provided by the Riena project, which makes the development of Riena based applications much easier. Stefan shows how to use Riena by a running example application.

Kai Hackbarth gives a session about "OSGi for In-Vehicle Systems". He explains how car sellers benefit by using OSGi as basic platform for the products. In the session Kai gives also a nice overview of the alternative platforms like android which are used in vehicle systems. Good news there are already OSGi deployments, Kai gives some examples where OSGi is already deployed.

OSGi for In-Vehicle Systems

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Last but not least a really cool session on the topic how normal web application could benefit by using OSGi from Jan Ehrhardt. Jan shows the reality, the problems and why in many cases normal web applications not benefit by using OSGi. In the second part of his session he shows in which situations and how web application could benefit by using OSGi. In the last part of his session he shows how OSGi could be used in different Java EE environments e.g. embedded in tomcat, next generation EE applications server or OSGi as standalone application e.g. by using Apache Karaf.

Erweiterbare Webanwendungen mit OSGi

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Was again a great Users Forum Germany community event with great sessions thanks to the audience and the speakers. Only the date was not perfect chosen there where parallel in London UK a face to face meeting. Next time we will make it better I believe ;-)

In next couple of day I will make the last slides available I hope via slideshare and I will also linkt the link to the slides from the UFG website.

Links
http://germany.osgiusers.org/Main/OSGiUFGTreffen2011
http://www.slideshare.net/OSGiUsers

Spring Dependencies Structure

2011-10-30T18:29:00.003+01:00

Based on the "Diagram of Spring 3.0 module dependencies" from Osvaldas Grigas and the spring poms I made a simple yUML diagram. The diagram gives a short overview of the spring components and there dependencies. The green marked component is the core functionality of spring. The blue marked components provides functions based on the spring core.

Here the source of the yUML diagram, if you like to add some aspects or change something feel free and reuse it.

Links

Osvaldas Grigas, Diagram of Spring 3.0 module dependencies - http://ogrigas.eu/spring/2009/12/diagram-of-spring-3-0-module-dependencies
yUML - http://yuml.me

Spring Customize Annotation Scanning

2011-10-27T20:45:00.000+02:00

A really nice feature in Spring 3.0 is to have custom annotation. Why do you like to have own annotations? Because you could provide some semantic details about the component types. For example when you have a spring bean which is facade, why not use a annotation with the name facade?

Here the spring wiring for beans with the annotation facade:

The facade annotation:

And here a demo facade spring bean:

Spring DI with Java Standard Annotations

2011-10-27T20:23:00.002+02:00

In Spring it is easy to use the Java annotations for dependency injection (JSR 330), the Java annotation for post construct and pre destroy (JSR 250) and the Java API and Annotations for validation (JSR 303).

Why should I use this standard APIs and annotation in a Spring based application? Because when using this standards, the code has only dependency on standard APIs (javax). And the code could also be used in another implementation e.g. of the JSR 330.

Here a simple code snippet, which shows how to use this three Java standards in a spring bean.

And here the spring context configuration.

You could also mix the Spring annotations with the JSR 330 annotation. I think a good strategy is to use the JSR 330 annotation when every its possible and makes sense. In some cases you would use the spring specific annotations.

Which annotations do you prefer to use in a Spring application?

For more details see the spring documentation:
http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/

OSGi - How to get the Bundle Context in a Java Object Instance

2011-10-25T22:41:00.002+02:00

In most cases I use DS components, when I need the bundle context instance, the DS Framework injects me the bundle context in the activation method of my component. In most components I don’t like to have a dependency on OSGi APIs in my DS components, but thats another topic.

But sometimes I need an OSGi service or the BundleContext also in non OSGi / DS controlled class. E.g. when I like to write a JAX-WS web service class. There are many ways to get the Bundle Context into this type of Objects. One is to get the Bundle Context from the ClassLoader (which should implements the BundleReference interface). Here a short demo code snippet how to get the bundle API and also the bundle context of a class.

Comment: "However, this requires the code to have the permission to access the class loader." OSGi Core Specification see section 3.8.9.

Better implementation (thanks at Holger for the hint) is by using the OSGi FrameworkUtil class. See the second code snippet:

Another solution could be a holder class with a static field, which holds the actual bundle context instance. This also works when the code does not have the permission to access the class loader.

OSGi RFC-0172 Declarative Services Annotations Runtime?

2011-10-17T11:21:00.000+02:00

I had with Peter Kriens and Neil Bartlett on Twitter an interesting discussion about "Why the DS annotations in the DRAFT RFC-0172 Declarative Services Annotations should be process at runtime or compile time".

Here in this post I like to show my opinion why to process annotations at runtime.

Runtime Annotations kills DS lazyness?
Peter says at twitter "One of the best things about DS is its lazyness, we do not want to kill this".

My option is that with runtime annotations we do not kill the DS lazyness.
I think we do not need to scan the bundles classes and load them all, to find the DS components in the system. The simplest solution is to have the components with the full qualified class name in the bundle MANIFEST.MF here a sample code snippet:

The next thing is we need a way to read the annotations without loading the class into the class loader to support bundles e.g. with "Bundle-ActivationPolicy: lazy". All information for the DS model is in the system in the byte code (when we use runtime annotations). Because of that, we can read the information for the DS components from the bytecode. Reading annotations from the bytecode is a simple way to provide all the lazyness we have with the XML model. To show this I create a very simple prototype which use the javassist library to process the annotation at runtime in a OSGi framework see https://github.com/tux2323/annotation.processing.osgi/.

Reading Annotations at Runtime is a Performance Issue?
Peter says: "So byte code scanning does not take any time?"

XML reading at runtime does also take time; do you think reading XML can be done faster than reading byte code? All information are in the byte code is reading the byte code really a performance issue? I believe we could make reading the information for the DS components from the byte code almost as fast as reading it from the XML files.

Detect errors early?
Another statement from Peter pro XML model for DS is "Detect errors early".

Yes when the annotation is process at runtime, we won’t also have a static testing tool like bnd which checks at compile time, if everything is okay with the model and shows the problems in the IDE. Why do we need the XML model for doing this?

Why runtime Annotation?
Neil asked me on Twitter "Why would you do at runtime what you can do better at build time?".

My statement is: I would like to process the annotations at runtime, because I don't like to have information in two places in my system, only when there are technical reasons, for doing this. Because of that I think it would be nice to have runtime annotations.

When we have runtime annotations then the SCR Implementation can also decide to support them at runtime or generate at build time the XML Model e.g. via bnd. The most Java frameworks (EJB3, JAXB, JAX-RS...) use runtime annotations for their components, why do OSGi like to go a different way?"

XML and Annotations
Neil asks me on twitter "Sorry I don't understand. You want the runtime to look at both the annotations *and* the XML?"

Short answer: yes.

Long answer: When we support runtime annotations to describe DS components, which should be process at runtime, we must also support the old XML way to be backward compatible. So I like to have both XML and annotations like in the Spring framework. In Spring you could describe a bean via XML and if you like you can describe the spring bean by annotations.

Thanks
Thanks at Neil and Peter for the great discussion. At this point again I would like to say when you use at the moment DS you should use the cool annotations from BND. This is at the moment the best way to develop DS components, I think.

Links

RFC-0172 Declarative Services Annotations - http://www.osgi.org/download/osgi-early-draft-2011-09.pdf
Neil Bartlett @twitter - http://twitter.com/#!/njbartlett
Peter Kriens @twitter - http://twitter.com/#!/pkriens
javassist - http://www.jboss.org/javassist
BND - http://www.aqute.biz/Bnd/Bnd
Simple OSGi Annotation Processing Prototype - https://github.com/tux2323/annotation.processing.osgi/tree/master/annotation.processing.osgi

JUnit > 4.10 Rules

2011-10-15T16:41:00.000+02:00

It's been a long time ago that I last wrote about JUnit. A number of improvements and releases have been made. There have been lot improvements around the topic JUnit rules added. Today I had little bit free time to look into this new JUnit features.

Class Rules
Now there are also class rules in JUnit. A class rule extends the idea of test method-level rules and can be used to add logic, which should be invoked for or after all test methods. A simple use-case could be, when you need a HTTP server in the test, you could have a class rule to start and stop the server. Here a simple code snippet that starts and stops a HTTP server.

Test Sequence

Start HTTP Server
Run Test : invokeServletWithRequestOne()
Run Test : invokeServletWithRequestTwo()
Stop HTTP Server

Composition of JUnit Rules with RuleChain Feature
In JUnit 4.10 now you can order rules via a rule chain. This is really nice to reuse rules and combine them. Here a simple RuleChain code snippet.

Test Sequence

Start new Jetty Server (rule = ServerRule)
Create new Servlet Instance and add it to the Server (rule = ServletRule)
Run Test : invokeServletWithRequestOne()
Remove Servlet from Server (rule = ServletRule)
Stop Jetty Server (rule = ServerRule)
Start new Jetty Server (rule = ServerRule)
Create new Servlet Instance and add it to the Server (rule = ServletRule)
Run Test : invokeServletWithRequestTwo()
Remove Servlet from Server (rule = ServletRule)
Stop Jetty Server (rule = ServerRule)

Interface MethodRule is deprecated
The type MethodRule is now deprecated because the name makes no sense anymore because now we have class and method-level rules. A rule now should be of the type TestRule.

Thanks
Thanks at David Saff and Kent Beck for the work on JUnit and the cool rule features we have now in JUnit.

Links

JUnit GitHub Project - https://github.com/KentBeck/junit
JUnit Portal - http://www.junit.org/
Blog Post about JUnit Rule and Logging - http://tux2323.blogspot.com/2011/06/test-logging-via-junit-rule.html

OSGi Declarative Service Naming and Implementation Patterns

2011-10-13T23:50:00.001+02:00

Here some simple OSGi declarative service (DS) naming and implementation patterns I prefer to use.

1. Naming Pattern - Component Name
A DS component name should end with Component e.g. RobotComponent.

public class RobotComponent implements Robot {}

2. Naming Pattern - Start and Stop Method
For methods, which should be called on, activate or deactivate a DS component the following names should be used:

start(…) and stop(…)
startup(…) and shutdown(…)
initialize(…) and deinitialize (…)
activate(…) and deactivate(…)

public class RobotComponent implements Robot {

public void activate(){...}

public void deactivate(){...}

}

3. Naming Pattern - Service Lifecycle Methods
For the service lifecycle method the following method name patterns should be uses:

bind${serviceName}(…) and unbind${serviceName}(…)
set${serviceName}(…) and unset${serviceName}(…)
add${serviceName}(…) and remove${serviceName}(…)

e.g. void bindRobot(Robot robot) and unbindRobot(Robot robot)

DS method name for bind more then one service instance 0..n or 1..n should become the name add* and remove*.

public class RobotComponent implements Robot {

public void setEngine(Engine engine){...}

public void unsetEngine(Engine engine){...}

public void addSensor(Sensor sensor){...}

public void removeSensor(Sensor sensor){...}

}

4. Implementation Pattern - Behavior Symmetry
When there is logic for start (activate) or set something there should always be logic for stopping or unset.

5. Implementation Pattern - Avoid Implicit Immediate Components
When a DS component not provide a Service then the component is immediate activate when all reference service are available. When the code is changed and the component know provide a service, then the component is activated when the first client component like to use the service. When a component should be activate immediate then I think avoid implicitly immediate components add always immediate=true.

6. Implementation Pattern - Use Annotations for DS Components
Use BND or Apache Felix SCR annotations to describe DS components.

Links

Apache Felix Maven SCR - http://felix.apache.org/site/apache-felix-maven-scr-plugin.html
BND Annotation - http://www.aqute.biz/Bnd/Components

10 min - Domain Driven Design (lightning talk )

2011-10-12T09:33:00.003+02:00

Here my slides from my lightning talk about Domain Driven Design. The slides I have not really needed in the lightning talk. Because my notebook crashed and I only could show slide number one. And because of that I only used the first slide. With the first slide I give a 10 minutes overview of domain driven design, keywords, patterns and core ideas. I think this basics ideas behind domain driven design every software developer should know.

Domain Driven Design - 10min

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I think the following patterns, keywords and ideas should be known by everyone how developed OO software:

Ubiquitous Language
Domain
Domain Layer
Entities
Value Object
Repository
Aggregate
Service
Factory (e.g. Dependency Injection, Spring, Google Guice...)
Assertion
...

For those who could not be in my lighting talk, should have a look at the domain driven demo application. Everyone should have read the book by Eric Evans about Domain Driven Design. Okay the book is not update at all, but I think the most stuff in the book is still correct.

Links and Ressources

Glossary of Domain-Driven Design Terms - http://domaindrivendesign.org/resources/ddd_terms
Eric Evans - Domain-Driven Design: Tackling Complexity in the Heart of Software -2003
Domain Driven Design Community - http://domaindrivendesign.org/
DDD Demo Application - http://dddsample.sourceforge.net/

Seitenbau Developer Convention 2011 - Getting started with Scala

2011-09-24T20:26:00.000+02:00

A week ends now the SDC = Seitenbau Developer Convention is over. Was a cool event again learned a lot about web development html5 with boilerplate, CouchDB, oAuth2, Android development, Gerrit and Skali.

Together with Dennis, I told a bit about the Scala language. Here are the slides of this Scala session

SDC - Einführung in Scala

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More about the SDC can be found here (there is also an android app in the android market)
https://www.seitenbau.com/sdc/timetable

Getting started with OSGi using a 3D OSGi Robot at OSGi Community Event 2011

2011-09-24T20:10:00.000+02:00

The OSGi Community Event 2011 in Darmstadt was a really cool OSGi conference at all. Thanks for the organizationof this nice Event and the lots of new ideas, comments and inputs from all the participants.

Here the slides of Jochen and my Mars Robot session.

Getting started with OSGi using a 3D OSGi Robot sample application - Christian Baranowski + Jochen Hiller

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And here the slides from the session about the Platform O.N.E.

Platform O.N.E. - Deutsche Telekom’s OSGi based Application Platform for Third Party Enabling - Elmar Brauch & Christian Baranowski

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More information’s about the sessions and also the slides can be found here
http://www.osgi.org/CommunityEvent2011/Agenda

JMock HasProperty Expectations

2011-07-31T12:07:00.000+02:00

Took me a while to define JMock expectations which verifies that a argument of mocked method has a defined set of properties with values.

Here my JMock based JUnit test:

Is there no better way to do this in JMock?

Top 10 Software Engineering Books – Must Read

2011-06-16T20:18:00.001+02:00

Today I gave a lighting talk at SEITENBAU, about my favorite top ten software engineering books. Here my top ten list of books, which every developer should read:

#1 - Andrew Hunt, David Thomas - The Pragmatic Programmer - From Journeyman to Master

#2 - Erich Gamma, Richard Helm, Ralph E. Johnson, John Vlissides - Design Patterns

#3 - Martin Fowler - Refactoring -Improving the Design of Existing Code

#4 - Eric Evans - Domain Driven Design

#5 - Kent Beck - Test Driven Development by Example

#6 - Alistair Cockburn - Writing Effective Use Cases

#7 - Scott Berkun - The Art of Project Management

#8 - Martin Fowler - Patterns of Enterprise Application Architecture

#9 - Joshua Bloch - Effective Java

#10 - Gerard Meszaros - xUnit Test Patterns

I think there are more books you should read as a professional developer, but this list is at the moment my top ten list of books I think should have read.

Top10- Software Engineering Books

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What are your favorite software engineering books? Send me comments or write me via Twitter.

Links

Stackoverflow recommended books for software engineering- http://stackoverflow.com/questions/131571/recommended-books-for-software-engineering
Top 100 Best Software Engineering Books- http://knol.google.com/k/top-100-best-software-engineering-books-ever

Sikuli – GUI Test Automation with Java Robot API and Images

2011-06-05T16:52:00.001+02:00

The Sikuli project provides a simple tool for automate and test graphical user interfaces (GUI) using images (screenshots). The idea is to find an element on the screen by a screenshot and not by XPath or ID. The tool can be used for all GUIs also web applications. It’s a nice idea below you can see a simple example.

The SIKULI project is based on the Java VM and also provides an API for writing the automation in Java here a JUnit sample test.

For real world web testing it is not the right tool I think, because it depends on the style of the elements. When the button style changed you need a new screenshot of the button. But it is a nice tool for simple automation tasks. Have also a look at screen casts on the project homepage.

Links:
- Project Home - http://sikuli.org/
- How to use Sikuli Script in your JAVA programs - http://sikuli.org/docx/faq/030-java-dev.html

Convert a simple CSV File with Groovy, Java, Scala, awk, Ruby, Python, PHP or Bash?

2011-06-05T14:12:00.005+02:00

Change Log:

05.06.2011 1:30 pm - Initial created Post with Groovy, Java, Scala, awk, Ruby, Python Implementation
05.06.2011 4:00 pm - Add PHP implementation and update voting (now you can vote for PHP).
06.06.2011 4:00 pm - Add Bash implementation and update voting (now you can also vote for Bash)

Which is the best programming language for converting a simple CSV into another format?

First I blogged three Java VM based solutions written in Groovy, Java and Scala to convert a simple CSV file into another format. Rainer sends me the Java based solution, yesterday Axel Knauf sends an awk based solution, Niko sends Ruby based solution, Hendrik sends a Python based solution, Sebastian sends me a PHP implementation and Julien sends a Bash version. Now there are a Groovy, Java, Scala, awk, Ruby, Python, PHP and Bash implementation.

Now here again a complete overview of the different implementations:

The Groovy Implementation:

The Java Implementation:

The Scala Implementation:

Here the shell command and awk script:

The pure Ruby Implementation:

The Python Implementation:

The pure PHP Implementation:

The Bash Implementation:

I'm curious whether there are other implementation proposals (Clojure, Perl, PHP, …), if you have one you could send me the script via Twitter or leave a comment here…

I am also curious which implementation Groovy, Java, Scala, awk or Ruby you like and why? I have create voting here:

Thanks Rainer, Axel Knauf, Niko Dittmann, Hendrik Heimbuerger S.Barthenheier and Julien Guitton for the Java, awk, Ruby Python, PHP and Bash implementation.

Links:

Java (Rainer) - https://gist.github.com/1006757
awk (Axel Knauf) - https://twitter.com/#!/kopfkind/status/77288701725638656
Ruby (Niko) - https://gist.github.com/1008877
Python (Hendrik) - https://gist.github.com/1008881
PHP (Sebastian) - https://gist.github.com/1008966
Bash (Julien) - https://gist.github.com/1009420
old blog post: Convert a CSV File with awk - http://goo.gl/U7onj
old blog post: Convert a CSV File in Groovy, Java or Scala? - http://goo.gl/AAE17

Convert a CSV File with awk

2011-06-05T12:00:00.005+02:00

Yesterday I post three Java VM based solutions written in Groovy, Java and Scala to convert a simple CSV file into another format. Today kopfkind sends me via Twitter a awk based solution.

Here the shell command and awk script to convert the CSV file:

Thanks a lot @kopfkind for this simple solution. I'm curious whether there are other implementation proposals (Python, Clojure, Perl, Bash, PHP, …), if you have one you could send me the solution via Twitter or leave a comment here.

I am also curious which implementation Groovy, Java, Scala or awk you like and why?

See also: Convert a CSV File in Groovy, Java or Scala?

Convert a CSV File in Groovy, Java or Scala?

2011-06-04T21:26:00.001+02:00

Last week I have simple task I must convert a simple CSV file into another CSV format. My first solution was a simple Groovy script. Then inforw sends me a Java solution, to show me that with Java it is no much more code then the Groovy implementation is. Today I wrote just for fun a solution in Scala, to see how the code looks in Scala. My favorite of the three implementations is at the moment the Groovy one. But I think the Scala implementation has the best readability. Below you see the three implementations.

I'm curious what you like, feel free for comments? And I would be glad if someone contributes even further implementation in Clojure, Python, Perl,… or even a better Scala, Java or Groovy implementation.

The Groovy Implementation:

The Java Implementation:

The Scala Implementation:

Thanks @inforw for the discussion and the Java implementation.

Test Logging via JUnit Rule

2011-06-03T09:10:00.002+02:00

In most cases it is not necessary to test logging, but in some situations you wont to check in a JUnit test that a log statement will be written, e.g in special error cases. When you use logback as logging framework the test can setup a ListAppender for a Logger and can implement a assert method which checks that the expected log statement is in the ListAppender list. But then the test is logback specific and has dependency on logback! When you use this approache in many JUnit test classes the test source has a hard dependency on logback and when you wont to change the logging framework all tests must also be changed. To remove this hard dependency you can use a JUnit rule, which capsulate the logback framework from the test source. The example here shows how a test and such a JUnit rule can look like.

Here the sample test for verify logging:

And here the logback specific rule:

Logging in JUnit Tests

2011-06-02T11:36:00.001+02:00

With a JUnit 4.7 rules it is easy to add logging support in JUnit tests. The example test bellow shows how to add simple logging for each test method and the result of the test.

For more details about logging in JUnit tests see the blog post "JUnit 4 Test Logging Tips using SLF4J".

Slides Agiles Lernen und Software Entwicklung das OSGi Code Camp

2010-11-06T15:33:00.000+01:00

Here the slides from the talk "Agiles Lernen und Software Entwicklung das OSGi Code Camp" which we have at OSGi Users Forum Meeting 2010.

Links

OSGi Users Forum Meeting Programm - http://germany.osgiusers.org/Main/OSGiUFGTreffen2010
Summer OCC 2010 Website - http://germany.osgiusers.org/Main/SummerOCC2010
Gource is a version control visualization tool. - http://code.google.com/p/gource/

Sonatype Maven Shell and Parallel builds in Maven 3

2010-10-16T17:38:00.001+02:00

Today I played around with the parallel build feature from Maven 3 and with the sonatype maven shell. The sonatype maven shell is based (required) on Maven 3. Here my first build performance results.

	Maven 3	Maven 3 (mvn -T 10)	Maven 3 (mvn -T 1.5C)	Maven Shell
mvn clean compile	ca. 5 sec	ca. 3 sec	ca. 4 sec	ca. 2 sec
mvn clean package	ca. 12 sec	ca. 10 sec	ca. 10 sec	ca. 7 sec
mvn package	ca. 7 sec	ca. 6 sec	ca. 6 sec	ca. 3 sec
mvn clean site	ca. 4 min	ca. 4 min	ca. 4 min	crashed
mvn javadoc:javadoc	ca. 56 sec	ca. 29 sec	ca. 29 sec	ca. 27 sec

More about parallel builds in Maven 3 here:
https://cwiki.apache.org/confluence/display/MAVEN/Parallel+builds+in+Maven+3

More about the maven shell from sonatype here:
http://shell.sonatype.org/index.html

Apache Maven 3 and the Maven Site Plugin

2010-10-16T16:57:00.000+02:00

Today I have a look on maven 3 features, when I start to build the maven site of my project it always failed. Because the configuration for the maven site was changed in the maven version 3.X. Here my first maven site configuration that worked for my project:

More about the maven site plugin configuration version for maven version 3.X here:
https://cwiki.apache.org/MAVEN/maven-3x-and-site-plugin.html

MS Paint Design Process

2010-09-12T22:25:00.000+02:00

Nice video how MS Paint was build.

OSGi Bundle Quality or Bundle Information Repository

2010-08-24T12:45:00.002+02:00

A lot of projects build their JARs as OSGi bundles e.g. Jersey. The quality varies from very good bundles up to the bundles they do not work they only generate a MANIFEST file. Often you spend a lot of time until you have your frameworks running in an OSGi environment. Even if these frameworks JARs are offered as OSGi bundles already. So Neil Bartlett came up at Twitter with the idea to build a portal where you can find information about the quality of OSGi bundles.

After the twitter post from Neil, I think about such a portal and here are my first ideas about such a information portal. I think first we need a small command line tool which implements a set of static and dynamic tests for OSGi bundles. Nice would be a set of plugins which integrate the tool into your build tool (e.g. maven, ant) or favorite IDE.

What kind of static tests should this bundle test tool support?

Check if the to test JAR (bundle) have a valid MANIFEST e.g. to check via Peter Kriens BND lib.
Check some MANIFEST pattern e.g. do the bundle import the exported packages, which is a OSGi best practice.
Do the bundle describe e.g. via extra configuration where to get the runtime dependencies e.g. via maven pom.xml? Provide this dependencies (JARs) all of the imported packages.
Use the bundle a framework for declarative services? E.g. do the bundle use DS, Blue Print, iPOJO, Pearbeary...
Which OSGi services does the bundle use e.g. configuration service, logging service etc.

What kind of dynamic test should the test tool provided?

Check if the bundle can be deployed in an OSGi container (equinox, felix,… therefore the pax runner can be used for implementation). The bundle should ship a reference set of runtime dependencies or provided a configuration file which describes where to get these dependencies e.g. via maven or ivy. The order in which the runtime dependencies will be started can be determined via a static test on each bundle (for implementation the BND lib can be used, or pax runner do this already?). In addition to the runtime dependencies it should be a possibility that a bundle can describe a set of system properties.
Test that the exported packages can be used from a bundle. There for a test bundle can be generated which use the exported package resources of the bundle under test.
Check that if a started OSGi bundle provides OSGi services.
When a bundle use a framework for declarative services e.g. DS, verify that the decelerated services are up and running in the service registry.
Check that a bundle restart works. Service is down and will be started again etc.

When we have such a tool to automatically verify the quality of an OSGi bundle and get a set of information about the bundle. A central information portal/repository would be very nice where you can submit your bundles and the checks will be run on your bundle and published. Where you can search for bundles and you get information where to download the bundle and a set of information of the quality of the bundle. I think such an information repository about OSGi bundles and there quality should be hosted under www.osgi.org.

Here some ideas how to submit a bundle into such an information repository/portal? I think the portal should provide a REST service and web form to submit bundles to check and to add to the repository. The runtime dependencies can submit as ZIP or as maven pom.xml or ivy configuration. For the REST service plugins for build tools and IDEs would be nice. E.g. a plugin for maven which will be bind to the deploy phase of maven, could automatically deploy the bundle to check also to the bundle information repository.

Is anyone interested to build the testing tool with me as an open source project? Or is there a cool tool out there which can do such tests? Please contact me or write a comment to the post?

Links:

OSGi Compliance Levels - Neil Bartlett
http://njbartlett.name/2010/08/24/osgi-compliance-levels.html

Eclipse Tipp Reloaded - Disable STS Dashboard On Startup

2010-08-15T13:43:00.001+02:00

Last year I wrote a blog entry how to disable the STS (Spring Tool Suite) dashboard on eclipse startup see here. In newer version of STS the option is now in the preference dialog of STS see the screenshot bellow.

Links

http://tux2323.blogspot.com/2009/11/eclipse-tipp-disable-sts-dashboard-on.html
http://www.springsource.com/developer/sts

Import a Clojure Leiningen Project into Eclipse

2010-08-15T11:45:00.001+02:00

To import a leiningen project in the Eclipse IDE add the eclipse leiningen plugin in the project.clj as dev-dependency.

When you now invoke the command "lein help" there is a new task called eclipse. Invoke the leiningen task eclipse via "lein eclipse". The eclipse leiningen tasks creates the eclipse projects files ".project" and ".classpath".

Now you can import the project in the eclipse IDE, therefore you can use the import eclipse wizard. Therefore select "File->Import->Existing Project into Workspace" then click the next button and select the leiningen project as root directory now you can import the project via click on the finish button.

When you have installed the eclipse plugin counterclockwise you can know develop with syntax highlighting, run the project and debug the project from the eclipse IDE.

Links

My first Clojure Web Application

2010-08-14T17:16:00.001+02:00

I’m a fan of LISP, so I'm known a fan of Clojure, because Clojure brings LISP features to the Java platform. I don’t know if Clojure is good programming language for production use or for my daily work, but it makes a lot of fun to develop in Clojure, just try it. My first step was to write in clojure a simple hello world web application.

I choose leinigen as build and dependency management tool and the clojure web framework Compojure to develop a super simple hello world web application.

Here are the steps how I create my first hello world web application in clojure in 3 minutes:

1.) Download Leiningen
Download the lein bash script from:

http://github.com/technomancy/leiningen/raw/stable/bin/lein

2.) Install Leiningen
Invoke the bash script with the follow command:

lein self-install

3.) Create a New Clojure Project
Creating a new project with leinigen, therefore invoke the follow command:

lein new helloworld-webapp

4.) Add Compojure Dependency
Add the compojure dependency to the project, therefore add the follow dependecies to the project.clj file.

5.) Create the Hello World Application
Add the follow lines of code in "src/helloworld_webapp/core.clj"

6.) Run the Web Application
To start the hello world web application invoke the follow command:

lein test

7.) Invoke the Application
Now you can use the simple web application in your favorite browser open the URL:

http://localhost:8080/

Source Code
The source code of this simple demo can be found on GitHub:
http://github.com/tux2323/clojure-helloworld-webapp

Links

http://github.com/technomancy/leiningen

http://github.com/weavejester/compojure

http://weavejester.github.com/compojure/docs/getting-started.html

Gource - SCM Visualization

2010-07-19T23:55:00.001+02:00

Gource is a cool open source tool under GPL v3 for version control visualization. With Gource you can visualize the commit history of the project as an animated tree. Its cool to see how a project grows over the time and which people are involved in the project. Here a sample video of the SVN log of the OSGi sample project mars robot from the Summer OSGi Code Camp 2010.

Links:

Gource Project site - http://code.google.com/p/gource/
SVN Visualization with Gource - http://code.google.com/p/gource/wiki/SVN
MAC Gource Support

Mars Robot OSGi Sample Project - http://code.google.com/a/eclipselabs.org/p/occ2010/

Summer OSGi Code Camp 2010 Konstanz

2010-07-18T00:15:00.002+02:00

Very nice code camp about OSGi topics with real craftsmanship, thanks to all participants.

More Information about the Campe here:
http://germany.osgiusers.org/Main/SummerOCC2010

Eclipse Key Scheme Version 0.0.1

2010-07-08T22:36:00.003+02:00

The Version 0.0.1 Plugin can be downloaded here:
http://github.com/tux2323/com.github.tux2323.eclipse.keyscheme/downloads

The Key scheme extends the default eclipse key scheme and adds the follow shortcuts:

STRG+SHIFT+P Show Perspective dialog
STRG+SHIFT+S G Generate Getter and Setter
STRG+SHIFT+S T Generate toString()
STRG+SHIFT+S D Generate Delegate methods
STRG+SHIFT+S C Generate Constructor using fields
STRG+SHIFT+S H Generate hashCode() and equals()
STRG+ALT+X+R Run...
STRG+ALT+X+D Debug...

Activate the key scheme in the eclipse preferences:

STRG+SHIFT+S

STRG+ALT+X

See also my post call for shortcuts here:
http://tux2323.blogspot.com/2010/07/eclipse-key-scheme-call-for-shortcuts.html

Eclipse Key Scheme – Call for Shortcuts

2010-07-06T15:13:00.002+02:00

In order to work efficiently in a development environment, I think you need an environment, which allows you to work exclusive with the keyboard. And you are rarely forced by the environment to switch back to mouse. Therefore in eclipse a cool set of keyboard shortcuts exists e.g. CTRL+1 for quick fix or refactoring rename CRTL+ALT+R. But some functions in eclipse have no default shortcut, for this function I defined always my own shortcuts. But often I forget to share these settings between my different eclipse installations and eclipse workspaces. Since I have some time I would now like to create my own key scheme plugin (see github).

To create a key scheme in eclipse, you must create a new eclipse plugin and use the extension point "org.eclipse.ui.bindings", see the sample plugin.xml below.

If you have any good ideas of missing eclipse shortcuts, feel free to write a comment with the idea thx...

Drawing and Creativity (German Post)

2010-06-27T11:00:00.004+02:00

Just reading slide:ology by Nancy Duarte and I come across with a nice quote from Bill McDonough. Unfortunately, I have the German edition of the book slide:ology, because of that the post is written in German.

Was machen wir in unserem Bildungssystem nur mit der Kreativität unserer Kinder?

„Wenn ich in einem Raum voller Sechsjähriger betrete und frage: „Wer kann hier zeichnen?“, heben alle die Hand und schreien: „Ich kann’s“. „Ich kann alles mögliche Zeichnen“. Und wenn ich in einem Raum voller diplomierter Akademiker komme und frage: „Wer kann hier zeichnen?“, findet sich kein Einziger. Was ist das nur für eine Art von Bildungssystem?“ - Bill McDonough

Ich kann das Zitat nur unterschreiben, meine Tochter kann eigentlich alles zeichnen, ich hingegen tue mir schwer mal schnell etwas zu skizzieren um einen Sachverhalt in einer Besprechung durch eine Grafik besser darlegen zu können. Aber ich arbeite so oft wie möglich dran damit ich wieder an die Leistungen meiner vierjährigen Tochter anschließen kann.

Die große Frage für mich ist wie kommt es dass viele die Begeisterung am zeichnen verlieren, die wir als Kind hatten? Und oft eine menge Text einer kleinen Skizze in einer Besprechung oder in einem Dokument vorziehen?

Ich glaube oft ist nur Angst, dass ein Dokument nicht professionell aussehen könnte. Meine Meinung ist, Inhalte müssen wieder im Vordergrund stehen, anstatt geschleckter Präsentation und Dokumente ohne Aussagekraft. Ich kenne sehr gute Dokumente die im Wesentlichen aus etwas Text und abfotografierten Zeichnungen aus einem Meeting bestehen die wesentlich mehr Inhalt haben als manch lange Spezifikation.

Dieser Post ist ein JA für mehr handgemachte Zeichnungen, Grafiken und weiniger Text, Bla Bla in Meetings und Dokumenten. Auch wenn die Zeichnungen keinen Künstlerischenwert haben, wenn Sie helfen Inhalte effizient zu vermitteln war es nie ein Fehler den Stift in einer Besprechung in die Hand zu nehmen egal wie die Zeichnung danach aussieht.

Regular Expression with Comments Java

2010-06-14T23:44:00.001+02:00

Here a simple RegEx in Java with embedded comments.

Review Eclipse Helios RC4

2010-06-13T01:46:00.013+02:00

Change Log

2010-06-14 - Add section about drag drop files as link in package explorer
2010-06-14 - Add screen shot to JDT open implementation section
2010-06-14 - Add a new section about the JDT code formatter on/off via comment tag.
2010-06-13 - Initial create the review post

Eclipse Helios is the annual release of Eclipse projects in 2010; this year 39 projects are part of the release. And here is my first contribution to the Helios Blogathon, more details on the Blogathon can be found here. Helios is the code name for this year collecting Eclipse release. The idea of such a release is to be simultaneously release a large quantity of eclipse sub projects at the same time. This gives the user an Eclipse platform with well-coordinated projects, which works together.

My blog entry should only gives an overview of my favorite Eclipse projects and what new feature I really liked in the Helios release of Eclipse. The projects in my post are only a very small sub set of the Helios release, see here all projects.

Preliminary first a big praise to the Eclipse developers and the community, Helios is again another great milestone and the best development environment we ever had. Ok I know there are other great IDE’s out there (Netbeans and IntelliJ) but how? I am in love with Eclipse, so please no flame war here. And also Eclipse is more then a IDE.

The Helios RC3 was for me already so stable, that I've had it in my daily work. E.g. I have used the RC3 coding in a workshop with customers and I can tell Helios runs on my Mac Book as stable as any Eclipse version has before. First important point Helios seems to run very stable! Initial tests on Windows 7 also showed significant improvements have been made for SWT and Windows 7. But on Windows7 and Eclipse I will not actually talk here because I’m a Mac user!

1. Eclipse Workbench
First a look at the basic Eclipse platform and what is new and what what pleases me.

Drag and Drop Files
In Helios you can drag and drop files and folders from the operating system in the Package Explorer, Project Explorer or Navigator view then a dialog popup where you can choose to copy the files or import the files as link.

Resource Filter
File system resources can now be filtered for each project.

Linked Resources
Linked resources can now be defined their locations relative to users defined variables.

Virtual folders
Virtual folders are a very cool new feature in Helios. A virtual folders is a new type of resource that exist only in the workspace and not in the backed directory in your file system. The function can be found in the advanced menu in the eclipse new folder wizard.

UNIX file permissions
Nice feature for Linux and Mac users. The full set of UNIX file permissions are now supported in the eclipse properties dialog of a resource.

Key bindings in Quick Access
The eclipse quick access (E.g. CMD+3 or CTRL+3) shows now the key bindings.

Comparing configurations in the Installation History
Now it is possible to compare the installation history, to see which plug-ins are installed and which are removed.

2. Eclipse Workbench Team
The eclipse runtime comes with a basic set of views, editors and wizards for SCM they will be used for CVS, SVN and GIT integration or other SCM systems.

Open With in Compare editor
Now there is a Menu Item open with in the context menu in the compare editor.

3. Eclipse Workbench Debug

Breakpoint Properties
The breakpoints view now provides detail panel to display and edit the breakpoint properties.

4. Eclipse JDT
The Java Development Tools are a very cool set of views and editors for java development, refactoring, debug and testing. Here the new feature I love in Helios version of JDT.

A nice overview off the new JDT features gives the eclipse Live screen cast here.

Open Implementation
Was a new feature in the eclipse Galileo release, now the function is also in the navigation menu and a key binding can be assigned.

Code Style On/Off Tags
Now there is new tab in the code formatter options of your code style. The tab is called “On/off Tags”, when you enable this feature you can specify regions in your code, which should not be touch, by the auto formatter.

Content assist for getter and setter
Now the getter and setter for field can be create via the content assist a good alternative to quick assist via CMD+1 (CTRL +1).

New Refactoring Pattern - Move type to new file
Now a private class can be moved to a file see the example in screen shot. A pattern I not often need but some times it is cool you can develop all in a file and then use this pattern.

Java Compiler Report missing @Override
When you have a Java 1.6 project the java compiler now reports missing override annotations that’s very cool. The feature must be activated in the compiler settings.

Compiler Setting Import / Export
The settings of the Java compiler can now be exported and imported. That’s a cool feature when you work with more then one workspace and on different machines.

New Build Path Error Decorator
Build Path error is now shown by an extra icon as decorator. That’s very cool when I for got to set the Maven Classpath Variable in my Eclipse I see its not a compile problem something with my build path do not work great feature.

Type Hierarchy
The Type Hierarchy has now the option that can be sent to the background.

Debugging Instance Counts
The Variables view has now a new column displaying the number of instances of a variable.

JUnit Result Import form URL
JUnit results can be import form a URL e.g. form a build server that’s cool.

JUnit Launcher Test Method
Now the test method can be set in the JUnit launcher. That’s cool when you like to run one test, in eclipse Galileo this works also but not over the launch configuration.

5. Eclipse PDE
PDE is the eclipse plug-in development tool suite. Because every eclipse plug-in is also an OSGi bundle PDE provides also a great tool suite for development of OSGi based applications.

Eclipse OSGi console
An OSGi console is now available for the running eclipse framework.

Export Target Content
It's now possible to export the contents of the target platform into a directory.
Cool feature to share a platform.

6. Eclipse Modeling (EMF, GMF…)
Eclipse Helios comes with a big suite of tools for model driven development. An overview of the cool tools is not scope of this post. Here the new feature in the eclipse modeling project I love.

Text Editor for EMF
Now in Helios there is really cool text based editor for EMF models.

EMF Tree Editor
There is new generic EMF Tree based editor in Helios with a integrated properties view.

EMF Compare
I cannot remember what I commemorated it there since Galileo, but a played around with the EMF generic model comparing tools and it looks great. You can use the EMF compare tool for all EMF based models also your own models which are based on EMF Ecore.

Eclipse GMF
Cool project I worked a longtime ago with it, when you like to create a graphical DSL this model driven tool is your fist choice I think. GMF provides a model driven approaches to create graphical editors for eclipse, which are based on EMF and GEF.

I don’t have the really review the Helios version, I created a small editor all works but I don’t find new feature compared to Galileo version. But I don’t spend much time in the review. What I can say that the basic functions works fine in RC4. And you can use the new EMF modeling editors to create the models but this not a GMF feature.

7. Eclipse Mylyn
Mylyn is a great eclipse tool for management tasks.

Mylyn WikiText
Mylyn provides now a cool WikiText editor, the editor can be used in Mylyn but also standalone or in any eclipse based application.

8. Eclipse Memory Analyzer
This is cool eclipse plug-in for memory analyzes to find memory bugs.

When you like to use the Eclipse Memory Analyzer the first step is to create a Java heap dump. This can be done when you have a server application over JMX see the screen shot, or over the default Java VM options to create a heap dump (therefore see the Java VM documentation).

When you have a heap dump you open it and then you can analyze the dump with the Eclipse Memory Analyzer. More details see the Memory Analyzer tutorial in eclipse help.

9. EGit
First time in simultaneous release of eclipse a EGit. EGit is GIT SCM integration in eclipse. The basic features are implemented. What is not in EGit 0.8.1 is a team synchronization view, but I hope in version 1.0.0 which comes at the end of the year I think, this is also implemented. I think the EGit developers do a very good job in such a short time such a cool integration respect and thanks.

10. Eclipse WTP
The WTP project provides a huge set of tools for web development specially tools for J2EE web development.

Web Modules 3.0 and JSF 2.0
WTP now supports web modules version 3.0, JSF 2.0 and for e.g. apache tomcat 7.0

Web Deployment Assembly
In the Helios WTP version is now a preference dialog to configure the mappings of the project folder to the deployment structure. That’s a very import feature in Galileo I do this in the project settings files by hand or mvn eclipse does it for me, but there was no dialog for it. This new dialog replaced also the buggy Java EE module dependencies from Galileo dialog.

JSF Facelet Support
The HTML editor supports know JSF Facelet, which are also part of the JSF 2.0 specification. Now the content assist in the HTML can be used to select the JSF components.

XPath 1.0 and 2.0 Processor
Now there is a XPath 1.0 and 2.0 processor in WTP.

11. Remote System Explorer

The remote system explorer brings an eclipse integration for SCP, SSH and other cool tools to manage remote systems. I use the remote system explorer to edit configuration file on remote systems e.g. on the testing environment with my favorite eclipse editors e.g. for XML configuration files. The remote system explorer brings also a set of cool tools to work with your local system.

Local Console Integration
Now there is integration of the local console e.g. bash in the Helios release. In Galieo I need to use for a local consol SSH now I use the bash native cool.

An alternative is to use the local shell feature see the screen shout bellow from the RSE project, but in this shell the TAB feature from the bash do not work. So I'm very happy about the new integration of my local bash in eclipse.

OSGi Console Services and Filter

2010-06-07T20:58:00.001+02:00

In the Equinox OSGi Console with the command services all running services will be listed. When you like to filter you can use the OSGi Filter Syntax. The filter I use often is services (objectClass=com.github.tux2323*) then all services which starts with the Java package com.github.tux2323 will be listed.

Example:

osgi> services (objectClass=com.github.tux2323*)
{com.github.tux2323.demo.chat.server.ChatServer}={service.id=26}
  Registered by bundle: com.github.tux2323.demo.chat.server_1.0.0.qualifier [1]
  No bundles using service.

A nice german article from Heiko Seeberger about OSGi filter can be found here.

My first op4j code

2010-04-21T21:51:00.001+02:00

I play around with op4j makes a lot of fun. Here my first op4j code:

// Create a array with out null and 0 values
Integer[] integers = Op.onArrayFor(1, 2, 3, null, 4, null, 0).removeAllNull().removeAllEqual(0).get();
  
// Assert
for (Integer value : integers) {
   assertNotNull(value);
   assertNotSame(0, value);
}

Link:

UML Talk Infos and Links

2010-04-19T19:39:00.003+02:00

Here some Infos around my german UML "Einführung in die UML" talk. More details about SDC see http://www.seitenbau.com/sdc/.

Here my slides:

2010 - Einführung in die UML - Seitenbau Developer Convention

View more presentations from tux2323.

Here some Links to the topics from the talk:

jSonde – Generate a UML Sequence Diagram

2010-04-11T19:37:00.004+02:00

The eclipse TPTP profiler has a very cool feature, create a UML sequence diagram from a profiling session. But the problem the TPTP profiling agent doesn’t run on my MacBook. So I looked for other free tools and I found jSonde an open source Java profiler (GPL).

jSonde can be used to generate a UML sequence diagram from a java application by profiling the app e.g. this can be used to document the actual implementation of a use case. How a this can be done, I will show step by step here in this post:

Step 1.) Get jSonde from http://www.jsonde.com/

Step 2.) Create a JUnit test case for the use case / function which you want to document, or when you do TDD look for an existing test...

Here the example code of my test:

@Test
 public void testPurchase() {

  Seller sellerOne = kasse.getSeller(100);
  Seller sellerTwo = kasse.getSeller(101);

  Position hose = new Position();
  hose.setDescription("Hose");
  hose.setPrice(2150);
  hose.setSeller(sellerOne);

  Position kleid = new Position();
  kleid.setDescription("Kleid");
  kleid.setPrice(2150);
  kleid.setSeller(sellerTwo);

  Sale sale = new Sale();
  sale.addPosition(hose);
  sale.addPosition(kleid);

  kasse.purchase(sale);

Step 3.) Run the test e.g. in eclipse (or in other IDE) with the follow VM parameter: “-javaagent${JSONE_PATH}/lib/jsonde.agent-1.0.0.beta7.jar=60001”

Step 4.) Start jSonde and click File -> New Project

Step 5.) Enter a project name and the namespace of the application then click Connect

Step 6.) After the test is pass, click sequence diagram and select the test method in the tree view

Here the full UML sequence diagram for the "Purchase" test implementation:

Links:

TwiP JUnit Test with more then one Parameter

2010-03-18T08:58:00.000+01:00

Here a example, how a JUnit test which use TwiP, can use more then one test parameter.

See also my previous contribution on TwiP here.

Links:

http://twip.sourceforge.net/

proposal SnakeYAML - Annotation YAML Loader

2010-03-09T22:52:00.000+01:00

Andrey posts a comment on my blog post "YAML with snakeyaml" with the following question: "But I recognize a need to help pure Java<->YAML transformations.
Do you have an idea how the API may look like ? (to say just 'as in XStream' does not help much...)"

So here a first shot how a annotation based framework can look like:

here the YAML code:

and here a proposal for the API client code:

Feel free for comments ...

TwiP for Parameterized JUnit Tests

2010-03-02T20:31:00.000+01:00

The native parameterized JUnit 4.X tests allows only one data set per test. With TwiP you can define one data set per test method, thats cool. Here a example parameterized JUnit test with TwiP:

What not works in TwiP is the tree navigation (tested only in eclipse), because the mapping between the test tree result and the test methods is done by the name in the result tree. But TwiP add the paramter of the run in the name and then the mapping don't work :-( see the screenshot bellow, when you click on a test method you become a error dialog:

Links:

YAML with snakeyaml

2010-03-01T22:43:00.005+01:00

I played a bit around with YAML, here my results. I have used the Java implementation snakeyaml. Unfortunately I have not found a implementation that use Java annotation for mapping between YAML and Java Bean Objects.

The Java bean code, for the configuration:

And here a small test which use snakeyaml to load the YML file:

There is also a cool plugin for YAML editor support in eclipse called yedit, here a screenshot:

Links:

zxing - 2D barcode image processing library

2010-02-19T09:08:00.000+01:00

zxing is library under Apache License for decode and encode 1d and 2d barcodes. I played with the online demo (not with the Library it self) “QR Code Generation” (this a application that encodes 2d barcodes) and with my mobile phone Nokia N95, which comes with an application to decode 2d barcodes with the mobile phone camera. It’s very cool decode barcodes with the mobile phone works very fast... Try it with the images bellow :-) and your mobile phones …

Here some screenshot what I have done, first I encode a 2d Barcode with QR Code Generation.

Then I can decode the barcode with my mobil phone.

And here the result of the decoded barcode

There is also another zxing demo application called Online Decoder, for decode a barcode when you have no mobile phone with a barcode decode application.

When I have time at weekend I will have a look at the Java library to get demos running local in my eclipse…

Links:
- zxing
- Online Decoder
- QR Code Generation

My First Eclipse ZEST Demo Application

2010-02-17T21:01:00.002+01:00

Eclipse ZEST is a very cool Framework based on Eclipse GEF, for creating graph based software visualization tools for eclipse, with a few lines of code. The PDE Dependency Visualization Plugin for example is based on ZEST, see also my pervious post here.

Good ZEST starting points are the nice examples apps in the Eclipse ZEST CVS.

Here a screenshot of my first ZEST demo application.

Links:
http://www.eclipse.org/gef/zest/
http://github.com/tux2323/bundleviewer
http://www.eclipse.org/gef/zest/snippets.php

Design by Contract in Spring Roo

2010-02-09T23:39:00.020+01:00

In Spring Roo they use a simple approach for Design by Contract (ok not real DBC only preconditions), looks nice for me here a code snippet from Spring Roo source code:

public MailProtocol(String protocolLabel, String protocol) {
 Assert.notNull(protocolLabel, "Protocol label required");
 Assert.notNull(protocol, "protocol required");
...
public AbstractInvocableMemberMetadata(String declaredByMetadataId, int modifier, List parameters, List parameterNames, List annotations, String body) {
 Assert.hasText(declaredByMetadataId, "Declared by metadata ID required");
...

I think the Spring Roo way is a good hint for Design by Contract / Preconditions as tests in Java, which is not support native in the Java language. The Java asserts can be disabled the spring roo Asserts throws RuntimeExceptions...

Other Java Framework for Design by Contract:

Oval - http://oval.sourceforge.net/
Design by Contract Framework for Spring Applications - http://springcontracts.sourceforge.net/home.html

Links:

Spring Roo Assert API - see Spring Roo GIT http://git.springsource.org/roo/roo/blobs/master/support/src/main/java/org/springframework/roo/support/util/Assert.java
Spring Roo - http://www.springsource.org/roo
Eiffel and Design by Contract http://www.eiffel.com/developers/design_by_contract_in_detail.html

Languages, which support real Design by Contract:

Eiffel - http://www.eiffel.com/
D
Spec# - http://research.microsoft.com/specsharp/

VisualVM Plugins for Visual GC and OSGi Management

2010-01-30T22:13:00.005+01:00

VisualVm is a management console based on the netbeans platform. For VisualVM exists a nice plugin called Visual GC for visualization of the Java GC.

The Visual GC Plugin for VisualVM

Also a Plugin for OSGi management exists which provides basic management function for an OSGi container e.g. equinox. To use the plugin a bundle, which exports the management functions, must also installed in the OSGi container.

OSGi Managment Plugin for Visual VM

For more info’s about VisualVM and the plugins look on the VisualVM page.

Links:

VisualVM Project Site:
https://visualvm.dev.java.net/
OSGi Managment Plugin Project Site:
http://wiki.chameleon.ow2.org/xwiki/bin/view/Main/AdminTools
Blog about VisualVM and OSGi:
http://ordinaryjava.blogspot.com/2009/06/visualvm-osgi-plugin.html
Blog about VisualVM and the standard plugins
http://pietrowski.info/2009/06/visualvm-performance-tuning-tool/

GWT Events and DeferredCommand - setFocus

2010-01-30T17:10:00.001+01:00

To run code after all event handler in GWT are invoked the class DeferredCommand can be used. A example for such a command could be to set a focus for a text field ...

Example code for set a focus:

DeferredCommand.addCommand(new Command() {
 public void execute() {
           testField.setFocus(true);
 }
});

Links:

Eclipse Hot Deployment Mode For Spring DM Web Bundle

2010-01-30T14:04:00.003+01:00

For developing web application in eclipse with spring dynamic modules (spring OSGi) there is no mode in which the web resource like JSP etc. will be refresh automatically in the tomcat container.

At the moment I must restart a war bundle when a resource changed and the war bundle will be redeployed by spring web bundle. The restart (redeploy) can be done in eclipse automatic when a resource in the eclipse project change with the STS features, see my previous post about STS (Spring Tool Suite). This is nice for Java classes but not for web resources like JSPs, CSS, etc.

How does the spring web bundle work? The bundle deploys (unzip) the war in a temp directory (can be specifiy by the system property java.io.tmpdir) and then start the deployment method of the container (context) e.g. tomcat in my case.

Example eclipse development project structure of a webapp for running in a OSGi container with spring web bundle.

At the development time e.g. in eclipse, normally we have no archive war or jar, we have a eclipse projects, with a war directory structure (see screenshot). So my idea was to patch the TomcatWarDeployer from the Spring Web bundle and put a hot deployment mode into it (Next step could be a own HotTomcatWarDeployer bundle). In the hot deployment mode the war must installed from a directory (not as jar or war archive) in the OSGi container (in my case the eclipse project folder). The TomcatWarDeploy then do not deploy the files in temp folder the deployer runs the webapp in the project folder e.g. in the eclipse project.

Here is the original spring code (class org.springframework.osgi.web.deployer.tomcat.TomcatWarDeployer )for the base directory:

private String createDocBase(Bundle bundle, String contextPath) throws IOException {
        File tmpFile = File.createTempFile("tomcat-" + contextPath.substring(1), ".osgi");
 tmpFile.delete();
 tmpFile.mkdir();

 String path = tmpFile.getCanonicalPath();
 if (log.isDebugEnabled())
  log.debug("Unpacking bundle [" + OsgiStringUtils.nullSafeNameAndSymName(bundle) + "] to folder [" + path
    + "]...");

 Utils.unpackBundle(bundle, tmpFile);

 return path;
}

And here the patched code (method createDocBase from the class org.springframework.osgi.web.deployer.tomcat.TomcatWarDeployer) with the hot deployment mode for tomcat:

private String createDocBase(Bundle bundle, String contextPath) throws IOException {
 try
 {
  String hotdeployMode = System.getProperty(TOMCAT_HOTDEPLOY);
  if(hotdeployMode != null && hotdeployMode.toLowerCase().equals("true")){
   if (log.isDebugEnabled())
    log.debug("HOT Deployment mode is active. Use this feature only for developing!");
   String workspace = System.getProperty(TOMCAT_WORKSPACE);
   if(workspace != null){
    if (log.isDebugEnabled())
     log.debug("HOT Deployment workspace is set to: " + workspace);
    File workspaceFile = new File(workspace);
    if(workspaceFile.exists()){
     String projectName = bundle.getSymbolicName();
     if (log.isDebugEnabled())
      log.debug("HOT Deployment project name is: " + projectName);
     File projectFile = new File(workspaceFile, projectName);
     if(projectFile.exists() && projectFile.isDirectory()){
      if (log.isDebugEnabled())
       log.debug("HOT Deployment project path is: " + projectFile.getCanonicalPath());
      return projectFile.getCanonicalPath();
     }else{
      if (log.isDebugEnabled())
       log.debug("HOT Deployment project does not exists!");
     }
    }
    else{
     if (log.isDebugEnabled())
      log.debug("HOT Deployment workspace does not exists!");
    }
   }
   else{
    if (log.isDebugEnabled())
     log.debug("HOT Deployment workspace path is not set, please set system property " + TOMCAT_WORKSPACE);
   }
  }
 } catch(Exception exp) {
  if (log.isDebugEnabled()){
   log.debug("Error initializing HOT Deployment!");
   log.debug(exp);
  }
 }
  
 if (log.isDebugEnabled())
  log.debug("Use the normal spring deploymode with temp directory.");
  
 File tmpFile = File.createTempFile("tomcat-" + contextPath.substring(1), ".osgi");
 tmpFile.delete();
 tmpFile.mkdir();

 String path = tmpFile.getCanonicalPath();
 if (log.isDebugEnabled())
  log.debug("Unpacking bundle [" + OsgiStringUtils.nullSafeNameAndSymName(bundle) + "] to folder [" + path
    + "]...");

 Utils.unpackBundle(bundle, tmpFile);

 return path;
}

That means you can change our web resources like JSPs etc. and the changes take directly effect. I think that’s the mode how I like to develop webapps no redeployment or file synch.

To use my patched spring web bundle you must install the patched bundle instead the normal spring web bundle (Version 1.2.1) in your OSGi container. Also the two system properties “org.springframework.osgi.web.deployer.tomcat.hotdeploy” and “org.springframework.osgi.web.deployer.tomcat.workspace” must be set see the screenshot.

So the solution is not very nice with the two system properties but at the moment it works for me. When you have ideas feel free for comments. I have also committed this idea in the spring dynamic modules (spring osgi) project JIRA see ticket http://jira.springframework.org/browse/OSGI-800.

Here you can get my example patched spring web bundle http://dl.dropbox.com/u/532968/spring-osgi-web-1.2.1-patched.jar

Have fun with the patch

Christian

Workshop – Building OSGi based applications - Darmstadt 15.04.2010

2010-01-26T22:04:00.002+01:00

Jochen Hiller and I are organizing for the OSGi User Forum Germany a workshop with the title “Building OSGi based applications”. The workshop location is Darmstadt and the date is 15.04.2010. You can now submit talks by sending a short abstract as email at workshop-germany@osgiusers.org, deadline for submit a talk is 01.03.2010.

More Information about the workshop see the workshop website: (German)
http://germany.osgiusers.org/Main/WorkshopBuildingOSGiApplication

For the workshop we provide an OSGi sample application, which is provided on GitHub: http://github.com/tux2323/osgi-kasse-example/

The follow YouTube Video (German) shows how-to import and run the sample application in eclipse.

So we will be happy to see you at the workshop in Darmstadt...

Christian

Eclipse Tipp - SpringSource Tool Suite - Auto Restart an OSGi Bundle in Eclipse

2010-01-19T21:04:00.002+01:00

SpringSource Tool Suite TM (STS) is a free (not open source) set of developing tools for spring based applications, it is eclipse based (an eclipse distribution, but can also installed as plugins in your eclipse instance).

The Spring Tool Suite comes with a very cool feature for developing OSGi based applications, the STS adds a listener to your eclipse project resource and when something changed (saved) the effected bundle will be automatic restarted. This is very cool for developing OSGi based application. To activate the feature you must enable the „Spring Dynamic Modules OSGi Bundle Updater“ see the screenshot.

The Option can be found under the project setting of your bundle. After activating the Bundle Updater in the project setting, add the follow argument “-console ${osgi.console.port}” to the command line arguments of your launch configuration.

Links:
http://www.springsource.com/products/sts

Painting by Hand with Bamboo

2010-01-16T22:12:00.007+01:00

I played around with BAMBOO, I tryed to draw a class diagram by hand. The idea to have a alternative to a Flip Chart in a meeting or workshop. But I think drawing on paper is much faster :-( ...

Here my first drawing with ArtRage (Demo Version) and Bamboo:

Do not Paint Work with Textual DSL instead

A better option can be to use a DSL instead of hand drawing stuff, e.g. in a brainstorming meeting. Here a example DSL for the picture bellow made with yUML:

[Seller]+1-0..*[Position]
[Sale]+->1..*[Position]
[Position]->1[PositionKey]

[Seller Repository]->[Seller]
[Position Repository]->[Position]
[Sale Service]->[Sale]

[Basar Kasse Service]->[Seller Repository]
[Basar Kasse Service]->[Position Repository]
[Basar Kasse Service]->[Sale Service]

And here the diagramm made by yUML from the DSL:

But I will work on my drawing skills, with BAMBOO, so maybe it will be come a alternative for me to get things fast on a screen ...

Links:
- yUML - http://yuml.me
- ArtRage - http://www.artrage.com/
- BAMBOO - http://www.wacom.eu/

Eclipse - PDE Incubator Dependency Visualization Plugin

2010-01-05T21:55:00.010+01:00

The PDE „Dependency Visualization“ plugin for eclipse is a very cool plugin to get a overview of the dependencies of a OSGi application. I think the plugin give a much clearer overview of the direct and indirect dependencies of an OSGi bundle then the old tree based PDE plugin does.

Example: Old PDE Dependency Plugin Tree Based:

Example: New PDE Dependency Visualization Plugin - Dependencies as Visualization:

Here the project website of the PDE Incubator Dependency Visualization plugin.

Eclipse - 3D Software Visualization

2010-01-05T09:27:00.001+01:00

Codstruction is a 3D software visualization tool more information on the project website.

Screenshot - Eclipse Equinox DS Implementation:

Eclipse - Software Visualization

2010-01-04T09:37:00.001+01:00

XRay is a nice eclipse plugin which does software visualization. It is not free for commerical use see the XRay page for more details.

Example: Package Dependency of eclipse equinox ds implementation

Example: Class Dependency of eclipse equinox ds implementation

For more information about software visualization in general have a look at the SE-Radio episode 130: Code Visualization with Michele Lanza.

Example - JMockContext - JUnit 4.7 Rule Support

2010-01-02T12:41:00.003+01:00

JMock now contains in the SVN trunk (http://svn.codehaus.org/jmock/trunk/jmock2) a class org.jmock.integration.junit4.JMockContext, the class is a JUnit 4.7 rule. With this new JUnit rule for JMock no JUnit runner is needed to use JMock in JUnit tests.

Here a small example test which use the new JMockContext rule:

import java.util.Observer;

import org.jmock.Expectations;
import org.jmock.auto.Mock;
import org.jmock.integration.junit4.JMockContext;
import org.junit.Rule;
import org.junit.Test;

// JUH @RunWith is not needed 
public class ExampleJMockContextTest {
    
    @Rule public JMockContext context = new JMockContext();
    
    @Mock Observer mockObserver;
    
    @Test public void expectNoException(){
        context.checking(new Expectations(){{
            oneOf(mockObserver).update(null, null);
        }});
        
        mockObserver.update(null, null);
    }
    
    @Test(expected=RuntimeException.class)  
    public void expectExceptionInSUT() throws Exception {
        
        context.checking(new Expectations(){{
            oneOf(mockObserver).update(null, null);
        }});
        
        mockObserver.update(null, null);
        
        throw new RuntimeException("Exception in SUT");
    }
    
    @Test(expected=RuntimeException.class) 
    public void expectExceptionInMockObjectTest(){
        
        context.checking(new Expectations(){{
            oneOf(mockObserver).update(null, null);
            will(throwException(new RuntimeException("Observer unavailable")));
        }});
        
        mockObserver.update(null, null);
    }
    
}

Manifesto for Software Craftsmanship

2009-12-23T21:06:00.001+01:00

http://manifesto.softwarecraftsmanship.org/

And here a very nice SE Radio episode about software craftsmanship with Bob Martin. http://www.se-radio.net/podcast/2009-11/episode-150-software-craftsmanship-bob-martin

JUnit 4.8 is released

2009-12-02T22:40:00.006+01:00

JUnit News

http://www.junit.org/node/581

and here a the release notes

http://kentbeck.github.com/junit/doc/ReleaseNotes4.8.html

Example JUnit Test With Test Steps

2009-12-02T22:23:00.002+01:00

Some times in a tests we want to have separate test steps that means to ensure the run of more then one statement e.g. assert statements.

Here a simple JUnit test, this tests show how such tests steps can look in a JUnit 4.X tests:

public class StackTest {

 Stack stack;

 @Before public void createStack() {
  stack = new Stack();
 }

 @Test public void push() {
  new Steps() {
   
   @Step public void setupPushElementsInStack() {
    stack.push("Element One");
    stack.push("Element Three");
    stack.push("Element X");
   }
   
   @Step public void verifyStackSizeIsThree() {
    assertEquals(2, stack.size());
   }
   
   @Step public void verifyStackElementOne() {
    assertElementIs(0, "Element One");
   }
   
   @Step public void verifyStackElementTwo() {
    assertElementIs(1, "XY");
   }
   
  };
 }

 private void assertElementIs(int position, String expected) {
  String element = stack.get(position);
  assertEquals(expected, element);
 }
}

And here the test result:

And here the code of the Steps class:

public class Steps {

 private List testStepFailures = new ArrayList();
 
 {
  run();
 }
 
 public final void run() {
  Method[] methods = getClass().getMethods();
  for (Method method : methods) {
   try 
   {
    Step step = method.getAnnotation(Step.class);
    if(step != null){
     method.invoke(this);
    }
   } 
   catch (Exception e) 
   {
    TestFailure failure = new TestFailure();
    failure.method = method;
    failure.exception = e;
    testStepFailures.add(failure);
   } 
  }
  if(testStepFailures.size() > 0){
   throw new TestStepsFailureException(testStepFailures);
  }
 }

}

Eclipse Tipp - Disable STS Dashboard On Startup

2009-11-30T23:22:00.002+01:00

Juh - I found the checkbox to disable the STS (SpringSource Tool Suite) in the Eclipse IDE:

Create a EMF Model Instance with JAVA internal DSL

2009-11-29T21:55:00.001+01:00

Sometimes a Java internal DSL is engough for creating a model instance (ok Eclipse xText is a cool tool :-)) a good example for Java DSL is the JMock DSL for creating mock objects. Here in my Blog I will show a small example for a Java internal DSL to get a EMF model instance. Here is the EMF ECore model (meta model) for my running example:

A small example model to describe components of an application and which services this components provides, only example stuff not a good model anyway.

Here a model instance with plain EMF Java code:

ComponentFactory factory = ComponentFactory.eINSTANCE;
   
Interface orderServiceInterface = factory.createInterface();
orderServiceInterface.setName("dsl.OrderService");

Port orderServicePort = factory.createPort();
orderServicePort.setProvides(orderServiceInterface);
  
Component order = factory.createComponent();
order.setName("order");
order.getPorts().add(orderServicePort);
  
Interface loggerServiceInterface = factory.createInterface();
loggerServiceInterface.setName("dsl.LoggerService");
 
Port loggerServicePort = factory.createPort();
loggerServicePort.setProvides(loggerServiceInterface);
  
Component logger = factory.createComponent();
logger.setName("logger");
logger.getPorts().add(loggerServicePort);
 
Application shop = factory.createApplication();
shop.setName("shop");
shop.getComponents().add(order);
shop.getComponents().add(logger);

And here the same model instance created with a Java internal DSL (Gof Builder Pattern):

Application shop = ApplicationBuilder.create("shop", new Components() {{

 component("order", new Ports() {{

  provides( OrderService.class );

 }});
 
 component("logger", new Ports() {{
  
  provides( LoggerService.class );
  
 }});

}});

Links:

In one of my next posts I will show the results of a Eclipse xText generated text DSL for the example model.

yUML - cool UML tool

2009-11-24T23:19:00.001+01:00

yUML is a web based small UML tool and it makes a lot of fun to create diagrams with it, here my first use case example diagram made with yUML

No real use cases only a diagram for test yUML...

Links:

JUnit Rule for jMock instead of the JMock Runner

2009-11-22T20:05:00.002+01:00

In JUnit 4.7 there is new feature called "Rules" see my previous posts...

The jMock framework comes with a JUnit 4.X runner for verifying the mock object states after each test run. Now with rules all the stuff of the runner can be done in one rule. I have implemented an example rule based on the JMock runner (see also jMock JIRA http://jira.codehaus.org/browse/JMOCK-237), here is the code of my example implementation:

import org.jmock.Mockery;
import org.jmock.lib.AssertionErrorTranslator;
import org.junit.Test;
import org.junit.rules.MethodRule;
import org.junit.runners.model.FrameworkMethod;
import org.junit.runners.model.Statement;

public class JUnitRuleMockery extends Mockery implements MethodRule {

 public JUnitRuleMockery() {
    setExpectationErrorTranslator(AssertionErrorTranslator.INSTANCE);
 }
 
 public Statement apply(final Statement base, final FrameworkMethod method,
   Object target) {
  return new Statement() {
   @Override
   public void evaluate() throws Throwable {
    try {
     base.evaluate();
    } catch(Throwable exp) {
     if(!isExceptionExpectedByTestMethod(exp, method)) {
      throw exp;
     }
    }
    assertIsSatisfied();
   }
  };
 }

 protected boolean isExceptionExpectedByTestMethod(Throwable exp, FrameworkMethod method) {
  Test test = method.getAnnotation(Test.class);
  return test.expected().equals(exp.getClass());
 }

}

Example Test which use the rule:

import org.eclipse.osgi.framework.console.CommandInterpreter;
import org.jmock.Expectations;
import org.jmock.Mockery;
import org.jmock.integration.junit4.JUnit4Mockery;
import org.jmock.lib.legacy.ClassImposteriser;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;

// No jMock specific Runner needed only the default JUnit runner
public class FrameworkCommandProviderTest {

@Rule
    public JUnitRuleMockery context = new JUnitRuleMockery() {{
       setImposteriser(ClassImposteriser.INSTANCE);
    }};
  
 InternalSystemBundle mockInternalSystemBundle;
 
 Framework mockFramework;
 
 CommandInterpreter mockCommandInterpreter;
 
 FrameworkCommandProvider mockFrameworkCommandProvider;
 
 FrameworkCommandProvider frameworkCommandProvider;
 
 @Before 
 public void setUp(){
  
  // Create mock object for system bundle
  mockInternalSystemBundle = context.mock(InternalSystemBundle.class);
  // Mocking the getContext Method, returns always null
  context.checking(new Expectations() {{
   allowing (mockInternalSystemBundle).getContext(); will(returnValue(null));
  }});
  
  // Create mock object for framework
  mockFramework = context.mock(Framework.class);
  // Set the mock object system bundle into the framework mock
  mockFramework.systemBundle = mockInternalSystemBundle;
  
  // Create mock object for command interpreter
  mockCommandInterpreter = context.mock(CommandInterpreter.class);
  
  // Create mock object for the SUT class, this mock will be used to mock methods in the SUT
  mockFrameworkCommandProvider = context.mock(FrameworkCommandProvider.class);
  
  // Create the SUT object of type FrameworkCommandProvider
  frameworkCommandProvider = new FrameworkCommandProvider(mockFramework) {
   
   /** 
    * Mock the SUT Method getBundleFromToken(...)
    * All method calls will delegate to a mock 
    * of the same type then the SUT object 
    */
   @Override
   protected AbstractBundle getBundleFromToken(CommandInterpreter intp, String token, boolean error) {
    // delegate the call to a mock object.
    return mockFrameworkCommandProvider.getBundleFromToken(intp, token, error);
   }
  };
  
 }
 
 @Test(expected=RuntimeException.class) 
 public void _bundle_OneArgumentsAndBundleNotFoundByToken() throws Exception { 
  final String firstToken = "myBundleName[1.0.0]";
  // Setup mock context
  context.checking(new Expectations() {{
   // one argument
   one (mockCommandInterpreter).nextArgument(); will(returnValue(firstToken));
   // next calles return null
   allowing (mockCommandInterpreter).nextArgument(); will(returnValue(null));
   
   // getBundleFromToken returns null
   one (mockFrameworkCommandProvider).getBundleFromToken(mockCommandInterpreter, firstToken, true);
   will(returnValue(null));
   
  }});
  
  // invoke the _bundle() method
  frameworkCommandProvider._bundle(mockCommandInterpreter);
  
  throw new RuntimeException();
 }

}

xUnit test implementation pattern for mocking methods in a SUT object

2009-11-22T16:58:00.001+01:00

Simple test implementation pattern for mock a method in the SUT object. The pattern is interesting when you would refactor a method in legacy system. Before you can start with the refactoring stuff you must write a test for the method with a high coverage (Refactoring details see Martin Fowlers great book "Refactoring - Improving the Design of Existing Code").

The idea is to test only the legacy method you would like to refactor (to get quick a high coverage), there for we want mock all method calls which will be invoked from this method. Normal mocking frameworks like EasyMock or JMock for Java can create mock objects for interfaces and classes. This pattern shows how this tools can be used for mock an internal method in the SUT object.

The idea, overwrite all method which should be mocked in the SUT object and delegate the calls to a mock object of the same type as the SUT object.

Example setup code with JMock as mocking framework:
...

@Before 
public void setUp(){
   ...
   // Create mock object for the SUT class, this mock will be used to mock methods in the SUT
   mockFrameworkCommandProvider = context.mock(FrameworkCommandProvider.class);
  
   // Create the SUT object of type FrameworkCommandProvider
   frameworkCommandProvider = new FrameworkCommandProvider(mockFramework) {
   
    /** 
     * Mock the SUT Method getBundleFromToken(...)
     * All method calls will delegate to a mock 
     * of the same type then the SUT object 
     */
     @Override
     protected AbstractBundle getBundleFromToken(CommandInterpreter intp, String token, boolean error) {
         // delegate the call to a mock object.
         return mockFrameworkCommandProvider.getBundleFromToken(intp, token, error);
     }
   };
}
...

The code with a example test which expected a mock method call:
...

@Test 
public void _bundle_OneArgumentsAndBundleNotFoundByToken() throws Exception { 
 final String firstToken = "myBundleName[1.0.0]";
 // Setup mock context
 context.checking(new Expectations() {{
  // one argument
  one (mockCommandInterpreter).nextArgument(); will(returnValue(firstToken));
  // next calles return null
  allowing (mockCommandInterpreter).nextArgument(); will(returnValue(null));
   
  // getBundleFromToken returns null
  one (mockFrameworkCommandProvider).getBundleFromToken(mockCommandInterpreter, firstToken, true);
  will(returnValue(null));
 }});
 
 // invoke the _bundle() method
 frameworkCommandProvider._bundle(mockCommandInterpreter);
}
...

Downsides:

Much code for the test setup to overwrite all the methods which should be mocked in the SUT object
Only protected, package and public methods can be mocked by this approach
Private methods can't be mock with this pattern
In the test code it's not clear which SUT methods are mocked and which not

Here the whole example test code:

package org.eclipse.osgi.framework.internal.core;

import static org.junit.Assert.*;

import org.eclipse.osgi.framework.console.CommandInterpreter;
import org.jmock.Expectations;
import org.jmock.Mockery;
import org.jmock.integration.junit4.JMock;
import org.jmock.integration.junit4.JUnit4Mockery;
import org.jmock.lib.legacy.ClassImposteriser;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(JMock.class)
public class FrameworkCommandProviderTest {

 // Create mock context and activate mocking for java classes.
 Mockery context = new JUnit4Mockery() {{
     setImposteriser(ClassImposteriser.INSTANCE);
    }};
 
    InternalSystemBundle mockInternalSystemBundle;
 
 Framework mockFramework;
 
 CommandInterpreter mockCommandInterpreter;
 
 FrameworkCommandProvider mockFrameworkCommandProvider;
 
 FrameworkCommandProvider frameworkCommandProvider;
 
 @Before 
 public void setUp(){
  
  // Create mock object for system bundle
  mockInternalSystemBundle = context.mock(InternalSystemBundle.class);
  // Mocking the getContext Method, returns always null
  context.checking(new Expectations() {{
   allowing (mockInternalSystemBundle).getContext(); will(returnValue(null));
  }});
  
  // Create mock object for framework
  mockFramework = context.mock(Framework.class);
  // Set the mock object system bundle into the framework mock
  mockFramework.systemBundle = mockInternalSystemBundle;
  
  // Create mock object for command interpreter
  mockCommandInterpreter = context.mock(CommandInterpreter.class);
  
  // Create mock object for the SUT class, this mock will be used to mock methods in the SUT
  mockFrameworkCommandProvider = context.mock(FrameworkCommandProvider.class);
  
  // Create the SUT object of type FrameworkCommandProvider
  frameworkCommandProvider = new FrameworkCommandProvider(mockFramework) {
   
   /** 
    * Mock the SUT Method getBundleFromToken(...)
    * All method calls will delegate to a mock 
    * of the same type then the SUT object 
    */
   @Override
   protected AbstractBundle getBundleFromToken(CommandInterpreter intp, String token, boolean error) {
    // delegate the call to a mock object.
    return mockFrameworkCommandProvider.getBundleFromToken(intp, token, error);
   }
  };
  
 }
 
 @Test 
 public void _bundle_OneArgumentsAndBundleNotFoundByToken() throws Exception { 
  final String firstToken = "myBundleName[1.0.0]";
  // Setup mock context
  context.checking(new Expectations() {{
   // one argument
   one (mockCommandInterpreter).nextArgument(); will(returnValue(firstToken));
   // next calles return null
   allowing (mockCommandInterpreter).nextArgument(); will(returnValue(null));
   
   // getBundleFromToken returns null
   one (mockFrameworkCommandProvider).getBundleFromToken(mockCommandInterpreter, firstToken, true);
   will(returnValue(null));
  }});
  
  // invoke the _bundle() method
  frameworkCommandProvider._bundle(mockCommandInterpreter);
 }

}

Run the Example Test:

To run the test you need the equinox osgi implementation as SUT, you can get the equinox source from the eclipse CVS ("pserver:dev.eclipse.org/cvsroot/rt/org.eclipse.equinox/framework/bundles/org.eclipse.osgi/").

Links:

Tipp Eclipse JDT Java Editor - Option Escape text when pasting into a string ...

2009-11-22T14:47:00.001+01:00

Cool option in Eclipse java editor "Escape text when pasting into a string literal".

EMF - Create a Dynamic Model Instance

2009-11-09T23:52:00.001+01:00

For developing EMF models the option "Create Dynamic Instance" can be very usefull. When you have a EMF meta model and you want to create a first test instance of the meta model the option "Create Dynamic Instance"can be used see the screenshot...

For create Dynamic Instance do a right click on the RootObject of your model that you would want to instantiate. The screen shot bellow shows the editor for editing a EMF based model dynamic in eclipse as XMI.

More details on dynamic instantiation in EMF:
http://wiki.eclipse.org/Dynamic_Browsing_and_Instantiation_Capabilites_in_EMF

Eclipse Tipp - Java Type Labels on Java Files

2009-11-01T23:42:00.000+01:00

To see the type of a java file by an label in eclipse activate the option

Eclipse Preferences -> General -> Appearance -> Label Decorations -> Java Type Indicator

The result:

The Preference Page:

Link - comparison of the GIT and SVN commands

2009-10-20T08:55:00.000+02:00

Nice page with a comparison of the GIT and SVN commands. Good starting point for SVN users which switch to GIT.

http://git.or.cz/course/svn.html

PAX cool OSGi Utils

2009-10-18T10:46:00.000+02:00

PAX provides a set of cool tools for building OSGi based applications here the Link to the overview page of the PAX projects:

http://wiki.ops4j.org/display/ops4j/Pax

Maven Archetype Overview

2009-10-18T09:51:00.000+02:00

Here a nice overview of maven archetypes:

http://docs.codehaus.org/display/MAVENUSER/Archetypes+List

Good bye

Christian

JUnitExt Prerequisite as JUnit 4.7 Rule

2009-10-13T09:11:00.000+02:00

The JUnit 4 Extensions project provides a annotation for specify precondition for a test. For example you have a database integration test, it makes no sense to run this test when the database is down. Therefor you can use the JUnit 4 Extension annotation @Prerequisite. But the disadvantage is, you must use a JUnit 4 Extension specific JUnit test runner @RunWith(AnnotationRunner.class). The Problem with the runner is when you must use a other runner for example the spring DI test runner in the test the approach did not work well.

But a feature like the @Prerequisite annotation of JUnit 4 Extensions project is very nice to have. In JUnit 4.7 there for the JUnit rules comes in mind, here is a small code example how a rule solution for the @Prerequisite annotation can look like.

Here the test with the @Prerequisite annotation and without specific test runner:


public class DatabaseTest {

 @Rule
 public PrerequisiteRule rule = new PrerequisiteRule(); 
 
 @Test
 @Prerequisite(requires="databaseIsAvailable")
 public void testFindAllUsers() throws Exception {
  // Database test stuff here
 }
 
 @Test
 public void testGetDataSource() throws Exception {
  // No Database test stuff here
 }
 
 public boolean databaseIsAvailable(){
  return false;
 }
  
}

The test result will be:

This test without errors can look like this one:


public class DatabaseTest {

 @Rule
 public PrerequisiteRule rule = new PrerequisiteRule(); 
 
 @Test
 @Prerequisite(requires="databaseIsAvailable")
 public void testFindAllUsers() throws Exception {
  // Database test stuff here
 }
 
 @Test
 public void testGetDataSource() throws Exception {
  // No Database test stuff here
 }
 
 public boolean databaseIsAvailable(){
  return true;
 }
 
 
}

And here a very basic rule implementation for the test:


public class PrerequisiteRule implements MethodRule{

 public Statement apply(final Statement base, final FrameworkMethod method, final Object target) {
  return new Statement() {
   @Override
   public void evaluate() throws Throwable {
    Prerequisite annotation = method.getMethod().getAnnotation(Prerequisite.class);
    if(annotation != null){
     String requiresMethodname = annotation.requires();
     Method requiresMethod = target.getClass().getMethod(requiresMethodname);
     Boolean result = (Boolean) requiresMethod.invoke(target);
     if(!result.equals(true)){
      fail("Test requires "+requiresMethodname);
     }
    }
    base.evaluate();
   }
  };
 }

}

Ok the implementation of the rule is very basic there is no good error handling for example ...

Feel free for comments ...

Links:
- http://junitext.sourceforge.net/
- http://www.junit.org/

JUnit 4.7 Rule for cleanup EasyMock object after test

2009-09-30T18:26:00.000+02:00

I try the JUnit 4.7 rule feature and I wrote a super small ExternalResource class for easymock cleanup (reset) here is the example code that makes mocking setup easier:


import static org.easymock.EasyMock.*;

import java.util.ArrayList;
import java.util.List;

import org.junit.rules.ExternalResource;

/**
* Mock resource class for cleanup mock objects after each test run.
*/
public class MockResource extends ExternalResource {

private List mockObjects = new ArrayList();

public   T createMockObject(Class clazz) {
T mock = createMock(clazz);
mockObjects.add(mock);
return mock;
}

protected void after() {
for (Object mock : mockObjects)
reset(mock);
} 
}

/**
* Example test which use the rule for cleanup the mocks.
*/
public class ObserverTest {

@Rule
public MockResource mockResources = new MockResource();

Observer mockObserver = mockResources.createMockObject(Observer.class);

@Test
public void testObserver() throws Exception {
Car subject = new Car();
subject.register(mockObserver);
mockObserver.refresh(subject);
replay(mockObserver);
subject.setName("Porsche");
verify(mockObserver);
}
}

With the mock resource rule no tearDown Method will be need the reset is be done by the rule. Come to think of it, there will be sure more mocking work which can be done by a JUnit rule. So I think the rule feature is very nice and makes JUnit tests better to read ...

Cool JUnit 4.7 Stuff : JUnit and Files

2009-09-29T22:05:00.000+02:00

Here a very nice example how to work with temporary files in JUnit 4.7 here

JPA with Hibernate Criteria API

2009-09-28T00:41:00.000+02:00

I didn't know that with JPA Vendor Hibernate, the Criteria API of Hibernate can be used. That can be done by getting the Hibernate Session from the JPA Entity Manager.

Here a example code:


  Session session = (Session) entityManager.getDelegate();
  Criteria hibernateCriteria = session.createCriteria(Position.class);
  // List with all positions
  List list = hibernateCriteria.list();

Ok the question is would you like to have a dependency to Hibernate in your source code when you would use JPA, I think you wold not like to have, but technical it works...

Nicer would be a Criteria API that depends only on JPA and is not JPA vendor specific. For JPA 1 I didn't know a project that provides such a Criteria API that works fine, but in JPA 2 I think the Crititeria API would be part of the standard, so I think thats a good news.

Another example:


// Implementation with Hibernate Criteria
public List getPositionList() {
   Session session = (Session) entityManager.getDelegate();
   Criteria hibernateCriteria = session.createCriteria(Position.class);
   hibernateCriteria.addOrder(Order.desc("createTime"));
   return hibernateCriteria.list();
}

// Implementation with plain JPA
public List getPositionList() {
    Query query = entityManager.createQuery("SELECT p FROM Position p ORDER BY   p.createTime DESC");
    return query.getResultList();
}