Improving web application performance by parallelizing requests
Posted by Kris Geusebroek mid-afternoon: December 9th, 2009
For a web application i develop we had a problem with the performance. After a small investigation we found out that it had relations with the amount of requests to the server that were done.
The application is running in a browser (currently IE7) and browsers are generally limited to do not more then 2 parallel request to the same domain.(this has improved a bit in later versions of the browsers). In this post i will describe the quest for solutions.
Middleware integration testing with JUnit, Maven and VMware, part 1 (of 3)
Posted by Vincent Partington at around evening time: December 7th, 2009
For Deployit, XebiaLabs' automated deployment product for Java EE applications, we are always building and modifying integrations with middleware systems such as IBM WebSphere, Oracle WebLogic and the JBoss application server. These integrations are small enough so that they can be rearranged to get many different deployment scenarios. A typical step, as we call these integrations, would be "Create WebSphere datasource" or "Restart WebLogic Server". So how do the test that code?
We've had some success using FitNesse and VMware to do integration tests on our deployment scenarios. But there were a few problems with this apporach:
- We could only test complete deployment scenarios in this way. If we wanted to test just a single step, we had to make a deployment scenario that used that step just to be able to test it.
- Because FitNesse does not provide any feedback while a test is running and the steps, let alone the deployment scenarios, can sometimes take a while to execute, there was little feedback on the progress.
- While it is possible to debug a FitNesse Fixture using Eclipse the process is not very convenient when debugging a technical component such as this step.
- To verify that a deployment scenario has executed succesfully we had to extend our FitNesse Fixture often. And while debugging code under test in FitNesse is complicated enough, debugging a Fixture is even harder!
Clearly we needed a different approach if we wanted to develop new steps easily.
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Mocking the ‘unmockable’: too much of a good thing?
Posted by Andrew Phillips mid-morning: December 6th, 2009
Static calls, final classes, objects created in test code: there are few things some of the current mocking frameworks cannot handle. Using powerful approaches like bytecode instrumentation or custom class loaders, these libraries make code that was previously a 'no go' area amenable to unit testing. This, moreover, in an elegant and convenient manner that will feel familiar to developers used to 'standard' mocking frameworks.
The question is: does such power perhaps come with hidden dangers? Might it be possible that the ability to test more could actually result in less code quality?
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CQRS: Designing the Event Store
Posted by Erik Rozendaal mid-afternoon: December 5th, 2009
One of the things I like about CQRS is that many of the infrastructure components become simpler, at least compared to the classical ORM approach. However, some of these components have not seen widespread use in existing enterprise applications and will be new to most people. One such component is the Event Store that is used for persistence of the (transactional) domain in CQRS.
(more...)
Domain-Driven Design and Command-Query Separation example application
Posted by Erik Rozendaal in the early morning: December 3rd, 2009
Ever since attending Greg Young's Unshackle Your Domain talk at QCon '08 in San Francisco and a later two-day training course given by Greg Young I've wanted to build a sample application that made use of the principles of Command-Query Responsibility Separation (CQRS).
However, other interesting things intervened and I never got around to doing this.
But every few months we have a one day internal training course at Xebia Software Development and after Sjors Grijpink and I proposed to give a training on DDD and CQRS we got some time to actually prepare and implement a CQRS example application.
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Xebee Goes Live
Posted by Anurag Shrivastava mid-morning: November 30th, 2009
It started when Saket walked in to my room about a year ago with a proposal to setup a blog where all people from Xebia India can blog. I asked Saket to find right tools to build such blog and find contributors who will publish contents regularly. I thought that setting up a blog was easy but keeping it up-to-date was hard. Blogging is about publishing content rapidly, so less than a regular flow of content would mean losing readers.
Even in the small organisation like us things move at a slower pace so the idea of having a blog disappeared like many other great ideas our team comes up with every week, because implementing an idea is hard. Recently Narinder, Vikas and Sandeep showed renewed interest in setting up a blog site for Xebia India. So quickly a word press theme was developed and a technical infrastructure is created to host the blog site. (more...)
Guaranteed Delivery in Spring Integration
Posted by Wilfred Springer just before lunchtime: November 27th, 2009
This is not a rant against ESB. I am not saying that ESBs never have a purpose, nor suggest that it's all just a scam. If - after having read this post - you got the impression that I suspect a conspiracy behind ESB, then I want to tell you up front that this is certainly not what I intended to say.
Testing the testers: code samples from a TDD framework comparison
Posted by Andrew Phillips around lunchtime: November 26th, 2009
Some while back I was preparing a presentation on mocking and testing frameworks for Java. As part of the aim was to demonstrate some real, running code, I ended up spending quite some time copying, pasting, extending and correcting various examples gleaned from readmes, Javadoc, Wiki pages and blog posts. Since then, this codebase has been extended with various new features I've come across, and I've often referred to it for experiments, as a helpful reference, and suchlike.
I imagine this kind of "live" reference could also be useful to others, so I thought I'd share it. (more...)
IBM WebSphere scripting with wsadmin: containment paths, configuration IDs and object names
Posted by Vincent Partington in the early evening: November 23rd, 2009
In my previous blog on the deployment capabilities of the major application servers, I asked, as a joke, whether anybody knew the difference between containment paths, configuration IDs and object names in WebSphere's scripting interface wsadmin. I didn't get (nor expect 
) an answer. But instead of keeping you in the dark, this blog will explain the difference between these three and how you can translate between them.
Configuration ID
Configuration IDs are the most common id you will encounter when working with wsadmin. They uniquely specify an element in the configuration of WebSphere Application Server and are needed to modify the configuration with one of the commands in the AdminConfig object.
Maven appassembler Plugin: Dealing with Long Classpaths on Windows
Posted by ShriKant Vashishtha in the early afternoon: November 22nd, 2009
When it comes to generating command-line scripts for Java applications, Maven "appassembler" plugin comes handy. Its "assemble" goal does all the maven magic, i.e. searching the dependencies used for creating the Java application, adding them into the classpath of resultant script and finally copying all relevant jars to a single place. It was all working very nicely until I stumbled across the problem of long classpaths in the Windows OS.
Irrespective of whether you use DOS prompt or cygwin, Windows limits the length of environment variables. Though there are various options to overcome this problem using Java 6 wildcard classpath, mapping the path to some drive etc, they all look like workarounds to me as problem can recur again anytime.
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