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© 2013 IBM Corporation
BP203 Limitless Languages In The IBM Social StackMark Myers | London Developer Coop
© 2013 IBM Corporation
Agenda
Overview
The JVM
Programming paradigms
JVM Alternative Languages
Scala
Existing Code
Working With Domino
© 2013 IBM Corporation
This presentation skims over the hard work and dedication of thousands of developers passions, any
generalizations or sweeping statements are not intended to give offense, corrections are gratefully
received.
But most of all please interrupt!
Don't wait till the end of the session
© 2013 IBM Corporation
Who Am I?
MarkMember of the London Developer Co-op (londc.com)Developer from a support background12+ years on Domino, 15+ years in ITSpeaker at 2x Lotuspheres, 3x UKLUGs, 1x ILUGTwitter: @stickfight, Skype: Stickfight, Blog: stickfight.co.uk
© 2013 IBM Corporation
Tools We Used
IBM® Lotus® Notes® version 8.5.3
IBM Lotus Domino® version 8.5.3
Eclipse 3.7 (indigo)
Scala plug-in 29
Various other software tools mentioned throughout this presentation
Most code and techniques we talk about should be applicable to other versions of Notes/Domino/Windows too
© 2013 IBM Corporation
Limitless Languages?
Limitless Languages=
Alternative JVM Languages
Alternative JVM Languages =
Any Language that Compiles to Java ByteCode
© 2013 IBM Corporation
Why this Session?
Existing and Traditional IT cant keep up with the speed of green field and start-up development
You need little or no Investment to get started and you don’t have to throw your existing Java stuff away
Its not all up to IBM to keep us up to date.
Never get left behind again
Its simple and helps your CV
Its Cool
Nearly all of you are already using an IBM alternative JVM Language (sort of)
© 2013 IBM Corporation
The JVM
The JVM (Java Virtual Machine) runs Java ByteCode
It’s Increased in reliability and performance since 1996
All variations of the JVM guarantees binary compatibility
Java ByteCode does NOT have to have been generated from Java, any Language that compiles down to ByteCode can run on the JVM
We will take a look at the Pack Leaders
After some boring stuff
© 2013 IBM Corporation
Dynamic Vs Static typed: Dynamic
In a dynamically typed language, every variable name is (unless it is null) bound only to an object.
Names are bound to objects at execution time by means of assignment statements, and it is possible to bind a name to objects of different types during the execution of the program.
LotusNotes = 8.5.4LotusNotes = “Awesome”
This does not cause an error, unless you for get which type the variable currently is
© 2013 IBM Corporation
Dynamic Vs Static typed: Static
In a statically typed language, every variable name is bound both to a type (at compile time) and to an object.
Once a variable name has been bound to a type (that is, declared) it can be bound (via an assignment statement) only to objects of that type; it cannot ever be bound to an object of a different type. An attempt to bind the name to an object of the wrong type will raise a type exception.
© 2013 IBM Corporation
Functional Programming
“functional programming is a programming paradigm that treats computations as the evaluation of mathematical functions and avoids state and mutable data.”
Think of the states a document goes through
An object which can be modified after it is created
-Wikipedia
A method of coding like Object Oriented Programming
© 2013 IBM Corporation
Functional Programming
Grants us greater modularity
Means code reuse and maintenance is easier
Immutable objects allows data to be accessed concurrently from multiple threads without locking
Why?
© 2013 IBM Corporation
JVM Alternative Languages
An agile and dynamic language
A Core of Java with lots of features inspired by languages like Python, Ruby and Smalltalk
Very small-zero learning curve
provides the ability to statically type check and statically compile your code ( good for speed)
Seamlessly integrates with all existing Java classes and libraries i.e. unlike a lot of other Alternative JVM languages you can include Java code in the same file as Groovy
One of Groovy's top companions is Grails, a high-productivity web development environment inspired by Ruby on Rails. not much use for domino designers but fab if you are having to build your own UI (used by sky)
© 2013 IBM Corporation
JVM Alternative Languages
A general-purpose dynamic programming language
Is a dialect of Lisp
Also runs on Microsoft's Common Language Runtime and JavaScript engines.
Used by Citigroup, Typewire, Tianya (largest forum in china), AltLaw.org (one of the first production websites to use it)
© 2013 IBM Corporation
JVM Alternative Languages
JRuby is an implementation of the Ruby programming language
JRuby is held to be faster than Ruby for most implementations (once loading the JVM is taken into consideration)
Jruby is called from Java using either the JSR 223 Scripting for Java 6 or the Apache Bean Scripting framework
LinkedIn uses JRuby for its front end
© 2013 IBM Corporation
JVM Alternative Languages
Jython the successor of JPython is an implementation of Python
Supports nearly all of the Core Python standard library modules and all Java Libs
Jython programs cannot currently use CPython extension modules written in C (although this is supposedly coming)
Wsadmin (webSphere Server command shell) and Bea WebLogic use Jython as their scripting language
© 2013 IBM Corporation
JVM Alternative Languages
This is the Actual Logo
Rhino
Kotlin
© 2013 IBM Corporation
Scala
Stands for “scalable language.” named for its ability to grow with user needs
Designed by Martin Odersky, creator of Pizza (the forerunner of Java generics), author of GJ compiler
"... if someone had shown me the Programming in Scala book ... back in 2003, I'd probably have never created Groovy."
- James Strachan, July 2009
© 2013 IBM Corporation
Scala
Under active development at Ecole Polytechnique Fédérale de Lausanne (EPFL) and in the open source community, also nicely funded by none corporations.
Programming in Scala second edition by Martin Odersky, Lex Spoon and Bill Venners
http://www.artima.com/shop/programming_in_scala_2ed
© 2013 IBM Corporation
Who Uses Scala?
FourSquare
Sony
Siemens
Électricité de France (EDF)
The Guardian
Xerox
IBM knows about it too, see Adrian Spender excellent presentation at http://www.slideshare.net/aspender/scala-introduction-6963846
And from IBM them selveshttp://www.ibm.com/developerworks/training/kp/j-kp-altlang/index.html
© 2013 IBM Corporation
Why?: Shorter / Less Boiler
// this is Javaclass MyClass {
private int index;private String name;
public MyClass(int index, String name) {this.index = index;this.name = name;}
}
// this is Scalaclass MyClass(index: Int, name: String)
http://stackoverflow.com/questions/2952732/samples-of-scala-and-java-code-where-scala-code-looks-simpler-has-fewer-lines for an extreme example
© 2013 IBM Corporation
Why?: Type Inference
Java – Static Type Good – Catch type errors BEFORE you runBAD – Verbose, bulky
Scripting LanguagesGood – Short , easy to codeBAD – You get to catch your errors in test/production
Scala (with Type Inference)Good – Catch Type Errors BEFORE you runGood – Short , easy to code
© 2013 IBM Corporation
Why?: Type Inference
val cost = new BigInteger("99999999")var stringcost = List("nine", "nine")Stringcost += cost
But Compiler still says no, when you assign the wrong type
You don’t have to assign a type here, it infers this from type of
data you try and put in the variable
© 2013 IBM Corporation
Why?: Unified types
All types are objects. (Int, Boolean,Double etc etc)
No more primitives ( no more double and Double)
All Mapped Automatically for integration with Java
All functions get the nice add-ons like toInt and toFloat for String
© 2013 IBM Corporation
Why?: Pattern matching
Not Limited to primitives
You can even call Class and Functions :-)
© 2013 IBM Corporation
Why?: Actors
Concurrency Made simple
Designed to get over the fundamental problems with Javas shared data and locks model
It is a share-nothing model all communication is doing by messaging
An actor is a bit like a thread with a mailbox for receiving messages
© 2013 IBM Corporation
Why?: Actor example
© 2013 IBM Corporation
Why?: Parallel Processing
How do you make this run in parallel?
© 2013 IBM Corporation
Why?: Parallel Processing
Now running in parallel
Calling thread WAITS for completion of computation
2 CPU Machine = 2 items running in parallel
© 2013 IBM Corporation
Sanity Warning! : Scalaz
A Plug in Library for Scala
An implementation of pure functional programming with very high-level abstractions represented by symbols
Awesomely powerful and concise but a steep learning curve unless you are familiar with the complexity and are dealing with things like Trading platforms
http://code.google.com/p/scalaz/
Danger Will Robinson
© 2013 IBM Corporation
Sanity Warning! : Scalaz
:'-(
© 2013 IBM Corporation
Cross Language Dependency
Existing Code
© 2013 IBM Corporation
Cross Language DependencyAfter Inclusion of a new Scala Class
© 2013 IBM Corporation
Installing
Scala has plug-ins for Eclipse, IntelliJIDEA and NetBeans ( http://www.scala-lang.org/node/91 )
I use http://scala-ide.org/ for the eclipse plug-in
Install Eclipse 3.6 (Helios) or Eclipse 3.7 (Indigo) and install as a standard plug-in site (http://download.scala-ide.org/releases-29/stable/site )
Restart and you’re done
© 2013 IBM Corporation
Nice and Simple in Eclipse
© 2013 IBM Corporation
Nice and Simple in Eclipse
© 2013 IBM Corporation
Working in Domino
Copy these 3 files to your ..\jvm\lib\ext directory (they are about 9meg in total and cause a noticeable pause if in the agent)
Restart and you’re done
© 2013 IBM Corporation
Working in Domino
Normal Java Class doing Stuff in Domino
© 2013 IBM Corporation
Working in Domino
Scala Class, containing an Scala Object, calling that Java Class
© 2013 IBM Corporation
Working in Domino
Export Class files to a Jar
© 2013 IBM Corporation
Working in Domino
Import Jar file into normal Agent
© 2013 IBM Corporation
Working in Domino
Calling the Scala Object from Within
a Java Agent
© 2013 IBM Corporation
Working in Domino
Be Still my beating heart!!!
45 © 2013 IBM Corporation
Legal disclaimer• © IBM Corporation 2013. All Rights Reserved.
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