Simple object in R Project

Let’s create an “Account” class using R language RC object with two methods: displayBalance and add.

Account <- setRefClass("Account",
  fields = list(name = "character", total = "numeric"),
  methods = list(
    displayBalance = function() {
      paste0("The account of", name, "is ", total, "$")
    },
    add = function(x) {
      total <<- total + x
    }
  )
)



Create an RC object, access it variable and call it methodes

myAccount <- Account$new(name="Martin Magakian", total=100)
myAccount$add(100)
balance <- myAccount$displayBalance()
print(balance)

will print on the screen:
The account of Martin Magakian is 200$

Simple S4 object with method in R Project

There is a better way to create a class in R using the RC method. Only if your object don’t interact with older (S3) object.

In this simple example I’m going to create an class “Person”, then create a methode “sayMyName” Continue reading

Docker install on Debian 7 Wheezy

Docker requirement for Debian

Docker is using the LXC – Linux Containers heavily.
Due to the lack of LXC on Debian 7 a newer Linux kernel is required.

I don’t advice installing a backported kernel on production. But I didn’t notice any bug on my personal Debian

This tutorial was made from Debian 7.4 and installed Docker 0.8
docker-debian-7
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EMR command line for Linux and Mac OS X

Amazon Elastic MapReduce make running Hadoop clusters seamlessly.
As most AWS product it can be used in command line making it scriptable and flexible.
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Installing Hadoop on Ubuntu

Hadoop is developed in Java and aim to run mainly on Linux.
In this tutorial I will demonstrate how to install and run Hadoop on Ubuntu 12.04. The setup will run Hadoop in a single node cluster.
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Loading Java jars programmatically

How to import a Java Jar at runtime:

URLClassLoader child = new URLClassLoader (myJar.toURL(), this.getClass().getClassLoader());
Class classToLoad = Class.forName ("com.MyClassName", true, child);
Method method = classToLoad.getDeclaredMethod ("myMethodName");
Object instance = classToLoad.newInstance ();
Object result = method.invoke (instance);

Runnable Java Jar by hand

Ho dear, why would you want to do this boring task by hand?
Probably only for learning or scripting the process.

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Runnable Jar using Maven with dependancy

Maven is a great tool when it come to repetitive task. Exporting a runnable jar with maven can be done thanks to the maven-assembly-plugin
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Create runnable jar with Eclipse

Eclipse make the process of creating an executable file very easy.
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What is a runnable jar file?

Is short it just a zip file, rename into a *.jar file.
It embed all compile java class file required for it execution.
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