20 December 2014

Reactive programming with Reactive Extensions (Rx)

Reactive programming is seeing a lot of interest these days. Reactive Extensions is one way of adressing the problems of asynchronous, event-driven programming. Originally developed in Microsoft, it is one of the libraries that they have open sourced and it is now quite popular also outside of MS. Netflix is now the poster boy for Reactive Extension and they run the Java version.

I have put together some resources for people wanting to have a look at it.

Here is a short interview with Erik Meijer, creator of LINQ and Rx.NET, where he explains Reactive Extensions in less than 15 minutes. High ROI!

This is the homepage of all the variants of reactive extensions. It is actively developed and now is nicely branded. Their resources page is extensive and worth a look : http://reactivex.io/tutorials.html.

This excellent blog post is what made reactive programming start to click for me. This is concrete, clear and well written.

Netflix' online tutorial for Rx.js. This is very good. It takes a while to get through the excercises where you implement map, filter, etc. but after that it is a very good intro to practical use of Rx. Highly recommended!

A series of blog posts turned into e-book that gives an intro to Rx.NET. If you're on the .NET platform this might be just what you need.

A couple of presentations by people on Netflix about how they are using Rx.Java. Jafar Husain and Ben Christensen are very good presenters and give a good overview.

A blog series about Rx.Java on Android but it explains Rx generally. Well written and helps you grok Rx easier.

There was a mini conference about reactive programming in London called React 2014. For all of us that could not attend the presentations are on YouTube.

13 December 2014

Reactive programming with actors

I have looked into reactive programming lately. Here are a few resources I've put together during my research.

The first resource is an introduction to the theory of actors from the horses mouth. Erik Meijer interviews Carl Hewitt, father of the actor model. They have fun and the explanation is clear and straightforward.

This presentation shows Jonas Bonér explaining the tenets of the Reactive Manifesto and how the Akka actor system adresses reactive programming.

Coursera has two courses that are relevant. The top link is about the Principles of Reactive Programming. Unfortunately the course has run and it has no future sessions scheduled yet, but it looks good. The other course is a "prereq" for the reactive course that teaches Scala.

Kresten Krab Thorup writes about how to think about actors when making actor systems.

A very nice practical write-up about using actors for parallell computing of a mandelbrot set. Well written and easy to understand.

Roland Kuhn is writing a promising book about Reactive Design Patterns. It is currently in the Manning Early Access Program but the first chapter that is an intro to reactive programming is freely available already.

Slideshare from Jonas Bonér. It isn't the same as watching the guy give the presentation but on the other hand you can get through the slides quicker.

The presentations from Scala Days 2014 are out on Parleys. There is a bunch of presentations on reactive programming which in Scala basically means actors.

04 October 2014

Rooting Samsung Galaxy S4 I9505 International Version

For a long time I have resisted rooting my phone. I haven't been entirely happy with the way Samsung has packed the phone with all kinds of apps but it hasn't bugged me enough to do something about it. Now I'm going on a flight and I wanted some games on the phone to shut the kids up and the phone is already full. And when I check which apps to remove I see that all the apps that I want to remove are Samsung apps that are locked to the phone and can't be removed.

Enough is enough so I start researching ways to root the phone at last. I am on OS X which basically narrows the options down to Motochopper. I actually tried that but it didn't work with my firmware. Possibly I could also use Jodin3. That looked so complex that I never got around to it.

The reason for that is that I stumbled across a very simple way of rooting the S4. It is all done by the application TowelRoot as shown on the instructions here : http://gs4.wonderhowto.com/how-to/root-any-samsung-galaxy-s4-one-click-0155622 . Very straightforward and easy. And it actually works on my S4!

Basically what you do is first set up your S4 to allow sideloading of applications outside of the app store. Then open towelroot.com in your browser on the phone and hit the lambda to download the app. Then install it and run it. The app only has one button with the text "Let it Ra1n". Push the button and you've rooted your phone!

That was easy! Now I'm off to kill Flipboard, ChatON, WatchON and the rest of the bloat.

16 January 2014

Author: (no author) not defined in authors file

I'm still using git as my Subversion client and just today I came over this strange error message:

Author: (no author) not defined in /path/to/repos/authors.txt file

I'm not sure how the author can be missing on any commits in the Subversion repository, but the solution was quite simple. Just add an author called "(no author)" to the authors file like this:

(no author) = No Author <no.author@mail.com>

And then continue as normal with git svn fetch