Andrew Beacock's Blog

How to use Junction if you want Symbolic links in Windows XP

2010-01-31T22:32:00.000Z

Ever since I started developing using Unix machines I've wanted symbolic links in Windows XP. A recent pursuit of backup solutions left me really wanting symbolic links so I started the search. This blog post gave me everything I needed, using a tool from Microsoft's website called junction.

This command line tool created junction points between a symbolic name and a real folder on your hard drive (sorry network drives cannot be linked to).

I downloaded it and placed the junction.exe file in my C:\WINDOWS\system32 directory so it would be on my system path.

Below is my little walk-through of how to use junction.

I created a folder on my desktop called "junction test" and created a folder inside that called "folder":

I created a text file called "README.txt" inside the "folder" directory:

I opened a Windows DOS prompt (cmd) and navigated to the "junction test" folder on my desktop, then I ran the junction command like this:

junction "junction" folder

This gave the following output:

Junction v1.05 - Windows junction creator and reparse point viewer

Copyright (C) 2000-2007 Mark Russinovich

Systems Internals - http://www.sysinternals.com


Created: C:\Documents and Settings\abeacock\Desktop\junction test\junction

Targetted at: C:\Documents and Settings\abeacock\Desktop\junction test\folder

And the folder now looked like this:

If I double-clicked on the "junction" folder this is what I saw:

So as you can see the contents of the "folder" directory is now available in via the "junction" directory as well. Obviously the junction doesn't need to be next to the folder you want to link too (that would be of little use) but it can be anywhere on your harddrive (I was using it to point into my DropBox sync folder).

WARNING ABOUT JUNCTION

Only the junction tool knows that these folders are actually symbolic links, the rest of the Windows file system thinks they are normal folders. So for example you can simply delete the junctions via Windows and they go in your recycle bin and the folder that it points to stays where it was:

But if you then empty your recycle bin it also empties the contents of the folder that this junction was pointing at (which is probably NOT what you wanted to happen!):

So please remember to always use the junction command to create & delete junctions, you can also use it to show you which directories are actually junctions so you know if you should delete it or not, refer to the junction download page for more details.

It's a fantastic tool for Windows XP and very very handy for certain things but please bear in mind the warning above...

Technorati Tags: Symbolic Link, Junction, Microsoft, Andrew Beacock

Are your Maven profiles being picked up as 'default'?

2010-01-20T21:49:00.005Z

We recently noticed that the profile that we had marked as default in our Maven settings.xml file was not being set as the default. Like many examples on the web we had the following XML element set in the appropriate profile:

<profiles>
    <profile>
        <activation>
            <activeByDefault/>
        </activation>
    </profile>
</profiles>

After some searching we found this maven-users mailing list post detailing the solution.

<activeByDefault/> isn't enough to set the value, you need to explicitly set the boolean value to true:

<activeByDefault>true</activeByDefault>

Once we saved that change in our settings.xml file the profile was picked up as the default.

Technorati Tags: Maven, Andrew Beacock

A cool way to assert Lists using JUnit

2010-01-05T21:37:00.003Z

I found this JUnit tip recently over on Joe Walnes's blog, a rather nifty (and different) way to assert whether two Lists contain the same items:

JUnit/TestNG tip: Diffing Lists

Technorati Tags: JUnit, Joe Walnes, Andrew Beacock

Shorten links to be Twitter-friendly with j.mp

2009-12-08T20:08:00.000Z

Any Twitter users out there will know that URLs and 140 characters don't really mix that well, especially if you actually want to talk about the link as well! Typically you would use a URL shortening service such as the original tinyurl.com or one of the newer, shorter versions such as bit.ly.

Well there is a new kid on the block who's even shorter: j.mp

J.mp is another member of the bit.ly family just with two less letters, but it's going to be perfect for Twitter. I use the bit.ly bookmarklet to generate my links but it appears that there is not a version for j.mp yet, so I created my own:

Drag this link to your browser toolbar to get started: Shorten with j.mp

Technorati Tags: j.mp, bit.ly, tinyurl.com, twitter, Andrew Beacock

Summary of December's Manchester Spring User Group Meeting

2009-12-04T23:29:00.003Z

The December Spring meeting was held on Tuesday 1st December at the same venue as previous meetings. Two talks were lined up: one on Grails by Adam Evans and one on Spring 3.0 by Rick Evans.

Guy Remond of Cake Solutions started the evening off with introductions and explained that the Spring User Group was going to be expanding to become the 'Open Source Central User Group' so as to attract a more diverse audience. He also discussed the Open Source Central website which has plans to become the 'Hub for successful Open Source Enterprise Application Development'. It's going to pull various blogs together into one central place as well as offering video and podcasts of open source technologies. We were also some of the first people to get a physical copy of the Open Source Journal, a 5,000-copy print run (sponsored by Hays IT).

Practical Grails Demonstration by Adam Evans of CTI

Adam started his presentation with a brief run through of what is Grails, what is Groovy and showed that Groovy 'can' be just standard Java code. Grails applications compile cleanly down to a WAR file so deployment in your favourite appserver is easy. It uses GSPs and Sitemesh for the view layer, GORM for the database layer and supports a plugin-based architecture allowing you to 'plugin' views, controllers, domain objects, sessions and scripts.

He then went on to demo building a Grails application on the fly using SpringSource Tool Suite (STS). Unfortunately Adam's laptop wasn't up to the job of running STS (basically Eclipse) and Powerpoint at the same time and so he had major 'not responding' issues. Despite these technical difficulties Adam battled on filling the gaps with details of Grails (Grails 1.2 supports annotated Spring beans) and had the foresight to have a slide-based version of the demo to hand (major kudos to Adam!)

Then he 'built' a demo application which uses the Twitter API to perform a search on whatever you type into the input box. An interesting point was that the Twitter results were returned in JSON and the GSP expression language allows you to parse that data as if it was a first-class object, doing things like tweet.username.

Adam has also kindly posted a copy of his slides to SlideShare.net.

Guy then stepped back in to thank the sponsors of the event: Cake Solutions, OpenCredo, Skills Matter, FDM Group, Hays IT.

Spring 3.0 :: Weapons for the war on Java complexity by Rick Evans of QFI

Rick has been working with Spring since 2004 and has delivered loads of training courses on it as well. He started his presentation with a humorous youtube clip of a mega-beast of a shotgun, and his theme was whether various Spring 3 features were potato guns or super shotguns...

He started off with a brief overview of the changes made in Spring 2.5 ('ease of use') and then moved on to the new things in Spring 3.0 - key points: embrace Java 5 and heavy use of annotations as 'declarations of intent'. Spring 3 introduces SPEL - the Spring Expression Language as the default expression language across all the modules (Webflow, Batch, etc.).

REST is nicely supported now with both server-side support in the form of additional annotations for controllers: @PathVariable & the enhanced @RequestMapping, and client-side with the use of RestTemplates. Rick also mentioned the use of HiddenHttpMethodFilter to ensure that your standard browser forms could correctly call the right type of REST operation, silently mapping POSTs to DELETEs if required.

There are some new annotations in the Controller world: @RequestParam now has a 'defaultValue' attribute and @CookieValue and @RequestHeader allow you to extract data from cookies and HTTP headers accordingly. Validation has been revisited with a smattering of new annotations to ensure objects are @NotNull, have @Max and @Min values, etc. This is all activated via a Validator - either javax.validation.Validator or the old-skool org.springframework.validation.Validator.

Rick's final words were to do with the fact that there is no 'all encompassing' spring.jar anymore, it's split up into it's component parts and you pull in what you want - if you are using Maven or Ivy then I suppose this isn't a problem, but how do you deal with it if not? He also said that loads of stuff had been deleted, cleaned up or deprecated which is always a good thing - no point carrying cruft around.

Rick has also kindly posted a copy of his slides to Box.net

Then it was over the road to The Bowling Green pub for a pint on Cake Solutions (cheers Cake!) and a catch up with some old colleagues and meet some new north west developers...

Technorati Tags: Spring, Manchester, User Group, Grails, Adam Evans, Rick Evans, Andrew Beacock

Don't miss the December Manchester Spring User Group on Tuesday 1st December

2009-11-25T22:08:00.001Z

There was a little doubt recently if this event was going to take place as the main speaker had to pull out at the last minute. We now have a new and excellent speaker Rick Evans talking about Spring 3.0 - Weapons for the War on Java Complexity".

Doors open at 6pm and the main keynote normally starts around 6:30 (a chance for coffee and a chat before hand).It's in the usual place, just don't forget to register if you plan on going!

Technorati Tags: Manchester, Spring, User Group, Andrew Beacock,

Paste Email Plus - perfect for multiple text snippets in Firefox

2009-11-13T21:22:00.000Z

I've found recently when commenting on various blogs that I want to add a little footer to the comment with my name and blog address. For one or two comments typing it out by hand is fine but after a while I decided to try and find an automated way to deal with this issue.

So I was looking for something that allows me to enter multiple lines of text and then very easily insert this text wherever I choose. Well I quickly found the perfect solution - a Firefox add-on called Paste Email Plus by Chuck Baker.

You simply open the Paste Email Plus options window, enter a 'Label' to help identify this text, then enter the multi-line text in the 'Pastetext' field and click 'Save changes':

You are now set up and ready to start pasting that text snippet, in any area where you would normally type text just right-click and select 'Paste Email Plus' (below 'Paste' on my system) and then choose your labelled snippet:

You will now see your text chunk pasted into the text area wherever your cursor was at the time of the right-click!

Technorati Tags: Firefox, Chuck Baker, Andrew Beacock

JavaScript splits & matches with regular expressions (regex)

2009-10-28T22:18:00.000Z

I had been developing some client-side validation code in jQuery/JavaScript and using Firefox (and the excellent Firebug) to test and debug it. I was then asked to ensure that it worked in IE6 & IE7 and that's when the problems started.

Apart from the usual "which file does that line number equate to, and why does it not tie up?" issues I found that IE doesn't like taking a regular expression as it's parameter to the JavaScript split function. Firefox will happily accept this and works fine but IE doesn't. After some searching it appears that Firefox might be the odd one out and that it's non-standard to pass in a regex.

So what do you do if you want to split up a string based on a regular expression or rather a rule that can't be simply expressed in the way that the split function wants it? Wouldn't it be nice if you could ask if a string matches a regex but then use certain matched bits of the string in your next few lines of code?

Well you can, simply use the match method, surrounding the bits of the regex that you want to use later in parenthesis '(' and ')' and then you can use the global JavaScript variable RegEx to pull them out.

So if 1234-ABC is your text, and you want the numbers as one part and the characters as another then you would use this regular expression to match on: ^([0-9]*)-([A-Z]*)$. You can then get hold of the matched numbers bit with RegEx.$1 and the letters bit with RegEx.$2.

var productCode = "1234-ABC";
productCode.match(/^([0-9]*)-([A-Z]*)$/);
var numbers = RegEx.$1;
var letters = RegEx.$2;

Technorati Tags: Regular Expression, JavaScript, Andrew Beacock

How to disable the auto-completion 'bell' in Cygwin (using RXVT)

2009-10-16T21:38:00.000+01:00

If you have ever hit TAB a few times in bash (via RXVT) you will probably be greeted with the loudest 'bell' your PC can muster. After a while this gets pretty annoying so here's how to disable it if you are using RXVT inside Cygwin (this might work for other Cygwin terminals, I've just not checked)

Navigate to your home directory (normally just by typing cd and either edit or create a file called .inputrc

Add the following lines to the .inputrc file:

# Disable the annoying bell
set bell-style none

Save the file, close the terminal and reopen - you should now be bell-less!

Technorati Tags: Cygwin, RXVT, Andrew Beacock

How to get Scala working with the RXVT terminal on Cygwin

2009-10-09T22:16:00.001+01:00

Out of the box Scala support Cygwin, but this is only with the Windows command prompt-based bash terminal. If you have opted for the more UNIX-like terminal of RXVT then you will find that although the interactive Scala interpreter runs, you can't get it to do anything!

This has been raised as a bug (Ticket #2097) against the Scala project and graehl even posted a patch to changed the generation of the scala runtime scripts. As my Scala install was based on the downloaded Windows binaries (scala-2.7.6.final.zip) I couldn't directly use this patch, but I could examine it to see what graehl's fix was.

It appears that the key bit was to add the following Java command line option to the java statement that starts the scala interactive interpreter:

-Djline.terminal=jline.UnixTerminal

So the last line of my bin/scala file is:

exec "${JAVACMD:=java}" $JAVA_OPTS -cp "$TOOL_CLASSPATH" -Dscala.home="$SCALA_HOME" -Denv.classpath="$CLASSPATH" -Denv.emacs="$EMACS" -Djline.terminal=jline.UnixTerminal scala.tools.nsc.MainGenericRunner  "$@"

This appears to work, my interactive environment is now interactive!

Technorati Tags: Scala, Cygwin, RXVT, Andrew Beacock

Tommy Emmanuel being VERY creative with an acoustic guitar and some clever delay

2009-10-06T22:33:00.000+01:00

I don't often post about guitar stuff as I really want to keep this blog focused on the tech side of my life but I couldn't help but pass this YouTube link on:

Delay (& Creative Uses for It)

I started to watch it and was soon completely captivated by it, hope you like it too!

Technorati Tags: Tommy Emmanuel,, Guitar,, Andrew Beacock

The next Manchester Spring User Group meetup is 13th October

2009-09-29T21:04:00.000+01:00

Details of the next Manchester Spring User Group meeting are now available, as a taster for what it could be like I blogged about the last meeting. It looks like the main talk is going be from Jonas Partner on Spring Integration.

It's a 6pm start in the usual place (there's a lovely space-age building where the building site is on Google maps...) Remember there's free parking if you pull up to the barrier and mention the Spring User Group.

Hope to see you there - if you see a skinhead with glasses please come over and say hello! Oh and make sure you register to be guaranteed entry!

Technorati Tags: Manchester, Spring, User Group, Spring Integration, Jonas Partner, Andrew Beacock

Use Pidgin? Send screenshots with this great new plugin!

2009-09-10T21:57:00.001+01:00

I've been a big fan of Pidgin (formerly Gaim) for the past few years and one feature that I've always wanted was an easy way to send a screenshot to a buddy.

Well Raoul Berger obviously wanted it too and he's gone and developed the excellent 'send screenshot' plugin. Download and install it and make sure you have enabled it:

Then you can right-click and buddy in your buddy list and choose 'Send screen capture...' - your screen then darkens and you have a crosshair with which to select the region that you would like to send to you 'buddy':

You can also send a screenshot within a existing conversation by choosing the 'Convesation' -> 'More' -> 'Send screen capture...' option:

Another and fast, better way is to ensure that you have 'Show detailed information' selected in the 'Conversations' tab of the preferences and then you can simply right-click on the person's banner and select the option:

Also, after an email conversation with the send screenshot plugin author he's mentioned that he's looking to add a keyboard shortcut in the next release, which will make the whole process even slicker!

This is a great plugin and thanks to Raoul for taking the time to develop it (for a number of platforms I may add).

Technorati Tags: Pidgin, Screenshot, IM, Raoul Berger, Andrew Beacock

You NEED an X-mini II speaker for your MP3 player or iPod

2009-09-05T23:22:00.000+01:00

My wife was looking around for an external speaker for her MP3 player and in our searching we came across the XMI X-Mini speaker on Amazon. This little mono speaker has 105 five star reviews (out of 115) on Amazon and at the time was £20 (it's now £16.96 - was £15 for a short time).

It's an absolutely cracking speaker - the internal (rechargeable) battery lasts for hours and this thing can really pump it out - with the bass expansion chamber opened up it sounds amazing. We have used it as a speaker for an MP3 player as well as an output speaker for a guitar headphone amp - true rock guitar sound on the move!

If you are on the look out for a mini speaker for your MP3 player you will not be disappointed with an X-Mini!

Technorati Tags: , XMI, X-Mini, MP3, speaker, Andrew Beacock

Summary of August's Manchester Spring User Group Meeting

2009-08-16T22:01:00.001+01:00

The August Spring meeting was held on Tuesday 11th August at the same venue as June's meeting. The location was the the excellent University of Manchester Core Technology Facility which has free parking immediately outside the building, just press the buzzer and mention the Spring User Group and they let you in. The evening was introduced by Guy Remond of Cake Solutions who laid out the agenda.

The first talk was by Cornel Foltea of Cake Solutions entitled:

Hello World! (OSGi debugging in IDEA)

Cornel started out by giving a little overview of OSGi including a walk-through of the layered approach that the Open Service Gateway Initiative takes. He pointed out that it's key objectives were:

modularization
versioning
services
access control

The key component of any OSGi system is a 'bundle' which get deployed into an OSGi container. A bundle can then be dynamically installed, started, stopped, updated and uninstalled. They are modular in nature 'assuming nothing' - they are a JAR file, with it's contents protected from access unless it explicitly exports it's services and declares that it needs to import services offered by other bundles. Multiple versions of the same bundle can exist in the application server without conflicting with each other. OSGi also provides a Service Registry so that bundles can register (export) their services for use by other bundles.

Then Cornel went on to talk about what OSGi features IntelliJ's IDEA currently offers (a MANIFEST.MF editor and OSGi facet detection) and how to create a "Hello World!" application OSGi-style. The heart of this is the BundleActivator interface that you need implement to provide start and stop methods called by the OSGi application server (make sure you have downloaded the OSGi framework jar and add it to your classpath first):

package com.cake.dmsd.primer;

import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;

public class HelloWorldActivator implements BundleActivator {

    public void start(BundleContext context) throws Exception {
        System.out.println("Hello, World.");
    }

    public void stop(BundleContext context) throws Exception {
        System.out.println("Goodbye World.");
    }
}

Then you need to create the jar's MANIFEST.MF file to look like the following:

Manifest-Version: 1.0
Bundle-Name: Helloworld Bundle
Bundle-Activator: com.cake.dmsd.primer.HelloWorldActivator
Import-Package: org.osgi.framework;version="1.4.0"
Bundle-ManifestVersion: 2
Bundle-SymbolicName: helloworld
Bundle-Version: 1.0.0

Next he talked a little about setting up a remote server 'Debug Configuration' to allow IDEA to connect to the debug port of the dmServer (think this picture paints a thousand words!) - note the port number of 5005 and the fact that one of the parameters is -Xdebug:

Then he showed screenshots of shelled out to a console to start up the dmServer in debug mode by running:

./startup.sh -debug 5005

Once that was running the next step was to telnet to the dmServer running on the local machine and install the previously created bundle:

telnet localhost 2401
install

This step gives us a bundle ID (111 in Cornel's example) which refers to the specific instance of the bundle that we have just installed. This ID means that we can start and stop the bundle in the future using start 111 and stop 111 from the dmServer telnet console.

After Cornel's talk there was a little break which contained a mention of the Manchester Spring User Group sponsors: UMIC, Hays IT, Skills Matter, SpringSource & Cake Solutions and the new sponsor of the event: Keith Dauris of FDM Group (and it's associated FDM Academy).

The next talk was by Dave Syer and his talk was:

Spring 3.0 and Spring Batch Quick Tour

The first half of Dave's presentation was on the new features of Spring 3.0 and it was an excellent way to quickly get an idea of the type of stuff that's coming very soon. Spring 3.0 is the first version of Spring to only work on Java 5 and above, meaning that even more annotation support can be included. It's also introducing the Spring Expression Language (influenced by Unified EL++), full REST support and declarative scheduling & background task execution.

The Object <-> XML Mapping (OXM) has been revised to offer better support for REST stateless mappers and SQL XML access. The JDK PropertyEditors are being superceded by a revised binding & type conversion infrastructure. If you don't like writing your Spring bean configuration in XML then you are in luck with Spring 3.0 - you can now write it in Java (although I thought the idea of the config _not_ in Java was that you could change it without recompile? Maybe it would have been better to offer non-XML config via something like Groovy?)

Full REST support is now available (with a custom filter to help support PUT & DELETE) which includes annotations to be able to extract values from within the URL:

@RequestMapping(value="/rewards/{id}", method="GET")
public Reward reward(@PathVariable("id") long id) {
    ...
}

By using multiple @PathVariable annotations you will be able to offer some pretty 'deep' URLs, meaning that you won't be held back by the normal servlet mappings. Dave mentioned that someone was using some shell scripts consisting of wget/curl and pipes to create some pretty complex business logic. Non-HTML representations are also offered 'out of the box' so it's very easy to offer JSON, XML, ATOM, etc. without using complex URLs or query strings.

Scheduling has been given a complete overhaul in Spring 3.0, with enhanced java.util.concurrent support and a new TaskScheduler with triggers (a little like a simplified Quartz). There is a new @Async annotation (indicating that this method should be run in the background) along with an @Scheduled annotation for CRON-triggered methods.

Commons Attributes has now been removed along with traditional TopLink and Struts 1.x (subclass-style). Traditional MVC controllers are now marked as deprecated along with JUnit 3.8 support (as why would you not want to use JUnit the annotated way?) and several other outdated helper classes.

Expect a GA release of Spring 3.0 sometime after August, and a 3.1 release in Q4 2009.

Dave's second presentation was on Spring Batch, which he has been the project leader on for the past three years (version 2.0 was released back in April). He started with an overview of the architecture, saying that the Batch Infrastructure layer contains reusable low level stuff: flat files, XML, database configuration. The Batch Core layer contains the quality of service (QoS), audibility and management information and the Application is your business logic.

He said that in it's most basic form it was a "glorified state management system" and then proceeded to describe some of the key objects that make up the heart of Spring Batch (item oriented processing, the Step, Job & JobLauncher classes). The Quality of Service features are interesting as they allow you to detect job and item failures and then deal with them in one of three ways: try it again (transient), ignore it and maybe retry it later (Skippable), or mark it as needing manual intervention (Fatal).

Dave then gave a brief overview of a number of different strategies in which you can introduce multi-threaded behaviour to get your jobs done faster, these included:

Sequential Execution
Multi-threaded Step
Parallel Execution
Remote Chunking
Partitioning

Note: Please refer to Dave's slides for details regarding any of the above points...

Dave then gave us a little teaser with a run through of a rather useful-looking Spring Batch Administration interface, allowing you to view and manage your 'jobs' and the 'executions' of those jobs providing full details all the way down to stacktraces if the execution failed. This really did look like an extremely useful tool and one that will make Spring Batch much easier to 'sell' to management. Here are a few screenshots (kindly provided by Dave himself):

That was the official end to the evening, but SpringSource were buying the first round in the Bowling Green pub afterwards, so the majority of attendees carried on the discussions there (thanks for the beer SpringSource!).

Note: Both Cornel's and Dave's presentations can be found over on the Cake Solutions Blog.

Technorati Tags: Manchester, Spring, User Group, Guy Remond, Cornel Foltea, Cake Solutions, Dave Syer, SpringSource, Andrew Beacock

Don't forget the next Manchester Spring User Group meeting!

2009-08-07T13:00:00.001+01:00

Just to reiterate my blog post from a few weeks ago:

The next Manchester Spring User Group meetup is 11th August

I'll be there, come over and say "Hi" if you see a skinhead with glasses... ;)

Technorati Tags: Manchester, Spring, User Group, Andrew Beacock

Installing Ubuntu inside Windows XP using VirtualBox

2009-08-05T21:26:00.001+01:00

Since moving companies over a year ago I've missed my Ubuntu desktop having moved back to development on Windows. I've had a few comments that some of my old Ubuntu blog posts are now out of date and I've wanted a way to ensure that they remain 'correct'.

After discussing virtualisation with a friend I opted to install VirtualBox - an open source virtualization tool which is free and easy to get going. This blog post contains my installation notes from installing VirtualBox and then creating an Ubuntu9 virtual machine...

First I downloaded the latest version of VirtualBox (version 3.0.0) and selected the "VirtualBox 3.0.0 for Windows hosts". Then I downloaded the latest version of the Ubuntu Desktop edition.

After both of these were fully downloaded I double-clicked the VirtualBox installer and choose to install everything.

When the "not passed Windows Logo testing" alerts pop-up choose to "Continue anyway" then register if you wish.

Once it's all installed run VirtualBox and click "New" to create a new virtual machine.

On the "VM Name and OS Type" page I entered "Ubuntu9" as the name, and for the operating System I chose "Linux" and "Ubuntu" as the version. On the "Memory" page I chose the default option, same for the "Virtual Hard Disk" setup.

Within the "New Disk Wizard" I chose "dynamically expanding storage" for the "Hard Disk Storage Type".

This will have just created a new virtual server called "Ubuntu9" in a "powered off" state.

Right-click "Ubuntu9" and choose "Settings...":

Click "CD/DVD-ROM" on the left-handside, then click "Mount CD/DVD Drive", choose "ISO Image File" and click the folder icon to the right-handside:

The Virtual Media Manager windows appears.
Click "Add" and browse to where the downloaded Ubuntu ISO image was saved and click "Open". Then click "Select".

You will now be back at the Settings window, just click "Ok"

Now select "Ubuntu9" and then click the "Start" button

The virtual server now starts with the Ubuntu disk image auto-mounted and boots from this image. Use the cursor keys to select your default language and then choose "Install Ubuntu".

Ubuntu will start to install and load up the Gnome based installation wizard.

Select your language, timezone and keyboard layout when prompted.

You will now be presented with the disk formatting screen - choose "SCSI1 (0,0,0) (sda) 8.6GB ATA VBOX HARDDISK"

Enter some user information and login details and then click the "Install" button - this was a little scary as the host box is my main PC and although I'm running the installation via the VirtualBox it's still felt strange thinking that I might be clicking to reformat my main drive with Linux...

Ubuntu will automatically install after the disk formatting is complete, this can take a while. If it gets stucks at the "checking mirrors" stage then you might have some issues with the networking setup - the Ubuntu setup wants to be able to connect to the internet. I had to change my network settings from "NAT" to "Bridged" to get it working on my system.

If everything went ok you should now now be able to un-mount the Ubuntu disk image (via the Settings option) and start up your new Ubuntu machine:

That's it you can now use Ubuntu as if it was installed as your primary OS!

Technorati Tags: VirtualBox, Virtualization, Ubuntu, Linux, Windows, Andrew Beacock

A great answer to the "What is Agile?" question

2009-07-28T21:26:00.005+01:00

My friend David Draper has just posted a great response that he gave to a potential client recently in answer to the dreaded question "what, in a nutshell, does agile mean?"

Check out David's blog for his answer.

Technorati Tags: Agile, David Draper, Andrew Beacock

Better Java Dates, Times & Calendars with Joda-Time

2009-07-20T21:12:00.003+01:00

Anyone who has used Java to manipulate Dates will know that it's one of the most frustrating parts of the core APIs - it should just be so easy!

As an example, here is one way to create a 'date of birth' Date - in this object we want the time part of the Date to be all zeros (midnight):

import java.util.Calendar;
import java.util.Date;

Calendar calendar = Calendar.getInstance();
calendar.clear();
calendar.set(2004, Calendar.JULY, 10);
Date dob = calendar.getTime();

There are a few gotchas to be aware of here, first is that you can't specify the month value as just "7" or "07" as that would give the month as August (as month 0 = January!) and the other is that without the call to clear() the time part will be set to the time when the Calendar.getInstance() was called.

Now compare this to creating a 'date of birth' Date object using Joda-Time:

import org.joda.time.DateMidnight;

Date dob = new DateMidnight(2004, 07, 10).toDate();

The DateMidnight class indicates that the time part will be zeros (more explicit than the "clear()" method) and you don't have to use any constants to build up the months.

The Joda-Time package is rammed full of useful bits like this, including instants, periods, intervals, durations, etc. as well as full calendar support and the ability to 'freeze time' (very useful for unit testing).

It's a fantastic package and should be considered a replacement for the cumbersome java.util.Calendar class.

Technorati Tags: Java, Date, Calendar, JodaTime, Andrew Beacock

The next Manchester Spring User Group meetup is 11th August

2009-07-15T23:35:00.002+01:00

Following on from an excellent gathering in June, Guy Remond (MD of Cake Solutions) has announced the details of August's meeting:

"Introducing Spring Batch 2.0 plus Spring Framework 3.0 update" by Dave Syer:

Well known as lead committer to the Spring Batch project as well as having a major influence throughout SpringSource, Dave will be sharing insight into the use of Spring Batch, showing some demonstrations and unveiling enhancements (scalability, XML config, Java 5…) within Spring Batch 2.0. In addition he has promised some interesting thoughts on the long awaited Spring Framework 3.0.

There was a brief mention of Spring Batch at the last SUG meeting so I'm looking forward to finding out more...

Oh, don't forget to register for the August meeting over on the Spring User Group website.

Technorati Tags: Manchester, Spring, User Group, Spring Batch, Dave Syer, Andrew Beacock

Supporting the Oracle XMLTYPE datatype via JPA (Spring, Hibernate & JDBC)

2009-07-10T20:26:00.000+01:00

On a recent project I was tasked with developing two domain objects which mapped via JPA to a couple of tables. This would have been easy apart from one table used the the Oracle-specific XMLTYPE data type:

create table PERSON
(
 P_ID number not null,
 P_NAME varchar2(50),
 P_UPDATED date,
 P_XML xmltype
);

The XMLTYPE datatype is not supported by JPA (or any Hibernate-specific annotations) and so I had to use a different approach. I created the JPA-based Person class as normal, adding @Column annotations to the class, ignoring the P_XML column. I then added the following bit of code to be a placeholder for the XML:

@Transient
// required so that JPA doesn't try to persist it, we need JDBC for that
private String xml;

I then developed the JpaPersonDao as normal, using the getJpaTemplate() methods to select, insert and update the database. This handles all the columns except the XMLTYPE one - you need to use JDBC for that one due to the way in which Oracle expects the column to be filled and read.

My approach was to use the JPA-based DAO to perform most of the work loading and saving the rows, but hook in a JDBC-based DAO behind the scenes to handle the XMLTYPE column. By hiding it in the DAO, the users of the PersonDao will not have to worry about the special nature of the XMLTYPE column.

This is the JdbcPersonDao performing access to the XMLTYPE-based column only:

public class JdbcPersonDao extends JdbcDaoSupport {

   private static final String SELECT_XML_SQL = "select p.P_XML.getClobVal() from PERSON p where P_ID = ?";
   private static final String UPDATE_XML_SQL = "update PERSON set P_XML = xmltype(?) where P_ID = ?";

   public String getXml(Integer id) {
       Object[] args = { new Integer(id) };
       int[] argTypes = new int[] { Types.INTEGER };
       return (String) getJdbcTemplate().queryForObject(SELECT_XML_SQL, args, argTypes, String.class);
   }

   public void setXml(Integer id, String xml) {
       OracleLobHandler lobHandler = new OracleLobHandler();
       lobHandler.setNativeJdbcExtractor(new CommonsDbcpNativeJdbcExtractor());

       Object[] args = { new SqlLobValue(xml, lobHandler), new Integer(id) };
       int[] argTypes = new int[] { Types.CLOB, Types.INTEGER };
       getJdbcTemplate().update(UPDATE_XML_SQL, args, argTypes);
   }
}

And here are the important bits of the JpaPersonDao hooking into the JDBC-based one to ensure that the data stays consistent, both accesses to the database are within the same transaction and so are atomic:

public class JpaPersonDao extends JpaDaoSupport implements PersonDao {

   @Autowired
   private JdbcPersonDao jdbcPersonDao; // deals with the xmltype clob

   public Person getPersonById(Integer id) {
       Person person = getJpaTemplate().find(Person.class, id);

       if (person != null) {
           person.setXml(jdbcPersonDao.getXml(id));
       }

       return person;
   }

   public void savePerson(Person person) {
       getJpaTemplate().persist(person);
       getJpaTemplate().flush(); // forces the generation of an ID, required in the saveXml call
       saveXml(person);
   }

   public Person updatePerson(Person person) {
       // put the xml to one side as the merge clears out the transient field
       String xml = person.getXml();
       Person updatedPerson = getJpaTemplate().merge(person);
       updatedPerson.setXml(xml);
       saveXml(updatedPerson);

       return updatedPerson;
   }

   private void saveXml(Person person) {
       if (person.getXml() != null) {
           jdbcPersonDao.setXml(person.getId(), person.getXml());
       }
   }
}

Not the most elegant solution, but at least with the use of the @Autowired JDBC-based DAO the mess is hidden from the caller...

Technorati Tags: Java, Spring, JPA, JDBC, Hibernate, Oracle, XMLTYPE, Andrew Beacock

MP3 purchase comparison between Amazon.co.uk & Play.com

2009-07-04T11:36:00.001+01:00

My first foray into purchasing MP3 was from Amazon.co.uk some months back. It was a smooth experience much like buying anything else from Amazon and it's quirky MP3 downloader popped the nicely named MP3 files into my music folder in the normal directory structure of Artist name/Album name/track number & name.

This week I purchased an album from Play.com's MP3 catalogue due to it being a little cheap than Amazon. It's download format was a large zip file that had to be saved to the desktop, it's content was just the tracks - no artist/album directory structure, no track numbers. Because I don't have an iPod I had to look up the track listing on the net and rename the files just to put them in the right album order!

Next time I want to buy some music online I think I will be skipping Play.com's offering completely and paying the little more that Amazon.co.uk was charging - it will be worth it to just have my music just download straight into the right place rather than messing around with zip file and renames...

Technorati Tags: MP3, Amazon.co.uk, Play.com, Andrew Beacock

A new way to label in GMail (and the end of Right-Sided Labels)

2009-07-01T19:16:00.002+01:00

Back in March I blogged about my favourite GMail labs. One of them has died today - Right-side Labels.

Google are grouping labels together with Inbox, Drafts, Chats and other system labels, and so putting the labels over on the right-hand side doesn't make sense anymore.

The problem is, my GMail's not been updated yet so I can't play with the new features! :)

Technorati Tags: Google, GMail, Google Labs, Andrew Beacock

Be careful writing hashCode() methods when using HashCodeBuilder

2009-06-27T22:38:00.001+01:00

I've blogged in the past about using the Apache Commons EqualsBuilder and HashCodeBuilder to write simpler equals() & hashCode() methods.

My colleague recently blogged about a potential pitfall when using this approach, I'll summarise his findings here:

Be VERY careful when you ask the HashCodeBuilder to generate the resulting hashcode value:

Make sure you call builder.toHashCode() rather than builder.hashCode()

The first correctly generates a hashcode value based on the objects that you have added to the builder, the second gives you the hashcode of the builder object itself - definitely not the value you would be expecting (and would be a sure fire way to lose your objects in a Collection)...

Technorati Tags: Java, Apache Commons, HashCodeBuilder, hashCode, Andrew Beacock

How to escape text when pasting into Eclipse (including XML)

2009-06-23T20:49:00.004+01:00

When you paste text into Eclipse it does just that - places where the cursor is in it's full un-altered original form. This is fine most of the time apart from when you might want to copy a chunk of XML (or a similar large body of text). What you end up with in this case is the text pasted in with red lines everywhere because the text hasn't been properly escaped for Java code.

To enable escaping of pasted text open the Preferences panel ('Window' menu -> 'Preferences...' option), then choose: 'Java' -> 'Editor' -> 'Typing' and tick the box which says "Escape text when pasting in a string literal":

Now whenever you post in text which is broken over multiple lines, Eclipse will insert the relevant quotes of Java to make Eclipse happy.

Technorati Tags: Java, Eclipse, Editor, Escaping Text, XML, Andrew Beacock