Author: Robert Watkins

My name is Robert Watkins. I am a software developer and have been for over 20 years now. I currently work for people, but my opinions here are in no way endorsed by them (which is cool; their opinions aren’t endorsed by me either). My main professional interests are in Java development, using Agile methods, with a historical focus on building web based applications. I’m also a Mac-fan and love my iPhone, which I’m currently learning how to code for. I live and work in Brisbane, Australia, but I grew up in the Northern Territory, and still find Brisbane too cold (after 22 years here). I’m married, with two children and one cat. My politics are socialist in tendency, my religious affiliation is atheist (aka “none of the above”), my attitude is condescending and my moral standing is lying down.

Logarithmic Axes for ExtJS Charts

ExtJS includes a number of nice charting options. I mean, it’s no HighCharts or D3, but it’s not bad. But – it can’t do a logarithmic axis.

A logarithmic axis is useful for displaying data with a large range of values. Sometimes these values are already on a log scale – e.g. the Richter scale is a log scale, as is decibels. You can plot this on a normal linear numeric axis. But sometimes your values can’t be easily converted to a log scale. Maybe you’re plotting wealth distribution. Or, in my case, particle size distributions, where the sizes can range from metres down to microns. When dealing with something like this, you need a log axis.

Continue reading “Logarithmic Axes for ExtJS Charts”

Good tutorial on KeyChain and TouchID

Excellent introduction into using KeyChain and TouchID

AWS SDK 2.2, iOS 9, Xcode 7 – Adventures in Learning

Well, it’s been three-and-a-half years, but I’ve finally got around to getting to a point of writing an iOS app. I wouldn’t hold your breath waiting to get a copy, though – it’s purely for my private use, to aid in monitoring and administering the IES project.

After doing enough tutorials and similar exercises to be comfortable in building the app and the UI, I got around to trying calls to the AWS infrastructure. This proved a bit more difficult than I anticipated – hence this aide-mémoire. This isn’t going to be useful for non-iOS developers, and I doubt it’s going to have anything new for more seasoned iOS developer; only iOS noobs like me need bother.

Continue reading “AWS SDK 2.2, iOS 9, Xcode 7 – Adventures in Learning”

Fashionable ExtJS and Web Services

ExtJS 6 was released at the end of June, and one of the nicest new features in it is a change to their CSS tooling – they’ve replaced Compass with a JavaScript-based implementation of SASS called Fashion. One of the neatest features is “Live Update” – this takes the traditional ‘watch’ approach one step further, and instead of just rebuilding your CSS when you change a SCSS source file, it updates the CSS inside the running browser, without needing a page refresh! This is just awesome, and not something I’ve seen before in my (admittedly limited) experience with web development tools.

But there’s just one problem… you have to use the embedded web server started with the sencha app watch command. Which is fine if all you’ve got is a webpage, but if you’re dealing with web services (as so many web apps do), it’s a bit restricting – at least if you don’t want to configure your app or server to allow cross-site scripting.

But Live Update is too awesome to forego! What to do?

Continue reading “Fashionable ExtJS and Web Services”

Upgrading ExtJS – issues with templates

Quick _aide-mémoire_ so that I don’t forget. When upgrading from ExtJS 4 to ExtJS 5, if you’ve got any components that use a custom template, and expect `childEls` to be configured correctly, you need to add a `data-ref` to the generated HTML.

Quick aide-mémoire so that I don’t forget. When upgrading from ExtJS 4 to ExtJS 5, if you’ve got any components that use a custom template, and expect childEls to be configured correctly, you need to add a data-ref to the generated HTML.

Continue reading “Upgrading ExtJS – issues with templates”

ExtJS 5 and Gradle – Playing Together

Augmenting ExtJS with Gradle

ExtJS is pretty nice, overall, and it comes with a powerful build tool – Sencha Cmd.

Running builds with it can be tedious, because it doesn’t have any up-to-date checks – it constantly rebuilds stuff it doesn’t need. Oh, the time wasting!

As it turns out, Sencha Cmd is an Ant-based build tool. Which means we can create Gradle builds that augment it – given us support for such things as up-to-date checks.

Like this:

ant.importBuild 'build.xml'
def packages_dir = file('../packages')
clean {
doLast { delete 'bootstrap.js', 'bootstrap.css', 'bootstrap.json' }
}
refresh {
inputs.dir 'app'
inputs.file 'app.json'
packages_dir.listFiles().each() { package_dir -> inputs.dir new File(package_dir, 'src') }
outputs.file file('bootstrap.js')
outputs.file file('bootstrap.json')
}
js {
inputs.dir 'app'
packages_dir.listFiles().each() { package_dir -> inputs.dir new File(package_dir, 'src') }
outputs.file file("../build/${this.property('build.environment')}/${projectName}/app.js")
}
resources {
inputs.dir 'resources'
packages_dir.listFiles().each() { package_dir -> inputs.dir new File(package_dir, 'resources') }
outputs.file file("../build/${this.property('build.environment')}/${projectName}/resources")
}
sass {
inputs.dir 'sass'
packages_dir.listFiles().each() { package_dir -> inputs.dir new File(package_dir, 'sass') }
outputs.file file("../build/${this.property('build.environment')}/${projectName}/resources/${projectName}-all.css")
outputs.file file('bootstrap.css')
}
page {
// what are the inputs to page, I wonder?
// the outputs are the microloader.js and the index.html...
}
view raw build.gradle hosted with ❤ by GitHub
# the default Build Environment. Production is the default for Sencha Cmd.
# Use -Dbuild.environment on the command line to change, otherwise it doesn't get passed to the ant build properly
build.environment=production
# The project name. Should match what is in the app.json file
projectName=MyApp
view raw gradle.properties hosted with ❤ by GitHub

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Object equality is context sensitive

Equality is context sensitive. It’s very rarely as cut-and-dried as people think it is.

As a simple example, consider two $5 notes. I think everyone can agree that these notes have the same value – they are both worth $5. But are they equal?

Continue reading “Object equality is context sensitive”

Immutable objects the lazy way

Building properly immutable objects in Java can be annoying, especially if they’ve got a bunch of properties – too many to put into a readable constructor.1

You can implement the Builder pattern, but a lot of the time that just feels like overkill. But you don’t want to put in a bunch of setter methods, because that’s just asking for trouble. So what do you do?

Continue reading “Immutable objects the lazy way”

Java, Equality, Mutability

TL;DR version: Don’t implement equals() on mutable objects.

This is a post I’ve been tossing around for a couple of years, ever since a lunchtime debate with a colleague. It’s a simple statement: You shouldn’t implement the equals() method if your object isn’t immutable.1

Continue reading “Java, Equality, Mutability”