Changes for page WebObjects with Scala

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1	1	=== What is Scala? ===
2	2
3		-[[Scala>>http://en.wikipedia.org/wiki/Scala_(programming_language)]] is a modern, multi-paradigm JVM language that is most often compared to [[Groovy>>http://en.wikipedia.org/wiki/Groovy_(programming_language)]], [[Clojure>>http://en.wikipedia.org/wiki/Clojure]] or [[Erlang>>http://en.wikipedia.org/wiki/Erlang_(programming_language)]]. Its [[functional language>>http://en.wikipedia.org/wiki/Functional_programming]] foundations and built-in Actors library makes it especially attractive for concurrent computing. Scala is an abbreviation for "scalable" hinting at its design goals. In this day and age of multi-core processors concurrent computing can not be ignored.
	3	+[[Scala>>http://www.scala-lang.org/]] is a modern, multi-paradigm JVM language that is most often compared to [[Groovy>>http://en.wikipedia.org/wiki/Groovy_(programming_language)]], [[Clojure>>http://en.wikipedia.org/wiki/Clojure]] or [[Erlang>>http://en.wikipedia.org/wiki/Erlang_(programming_language)]]. Its [[functional language>>http://en.wikipedia.org/wiki/Functional_programming]] foundations and built-in Actors library make it especially attractive for concurrent computing. (Scala is an abbreviation for "scalable" hinting at its design goals). In this day and age of multi-core processors concurrent computing can not be ignored.
4	4
5		-Many of Scala's features have been designed with concurrency in mind, some of which may not be unfamiliar to Objective-C or WebObjects developers. Here's a summary:
	5	+Many of the design features of Scala have been chosen with concurrency in mind, some of which may not be unfamiliar to Objective-C or WebObjects developers. Here's a summary:
6	6
7	7	|= |= Objective-C |= Java |= Scala
8		-|= Immutability | Collections //e.g: NSArray/NSMutableArray// | No | Yes
9		-|= Closures | Blocks (//Extension//) | No | Anonymous Functions
	8	+|= Immutability | Partial - via Collections //e.g: NSArray/NSMutableArray// | No | Yes
	9	+|= Closures | Yes - via Blocks (//Extension//) | No | Yes - via Anonymous Functions
10	10	|= Static variables | Yes | Yes | No
11	11	|= Static methods or functions | Yes | Yes | No
12		-|= Concurrency | [[Grand Central Dispatch>>http://en.wikipedia.org/wiki/Grand_Central_Dispatch]] (//Extension//) | //Threads// | [[Actors>>http://en.wikipedia.org/wiki/Actor_model]]
	12	+|= Concurrency | Yes - via [[Grand Central Dispatch>>http://en.wikipedia.org/wiki/Grand_Central_Dispatch]] (//Extension//) | //Yes - via Threads// | Yes - via [[Actors>>http://en.wikipedia.org/wiki/Actor_model]]
13	13	|= |= Weakly Typed |= --Strongly Typed-- |= Strongly Typed
14	14
15	15	Other notable features include:
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25	25	=== Can WebObjects be Programmed In Scala? ===
26	26
27	27	Yes. It is very simple.
28		-Scala compiles to java bytecode.
	28	+By virtue of being a JVM-language, Scala compiles to java bytecode.
29	29
30	30	Furthermore, being a multi-paradigm language grants Scala easy WebObjects-interoperability.
31	31
32	32	===== Caveats =====
33	33
34		-Legacy tool support is often cited as a weak point. If your Application class is in Scala then you will have to create an Eclipse launch configuration manually. Also the [[Scala plugin>>http://www.scala-ide.org]] can be slow at times and sometimes buggy.
	34	+Legacy tool support is often cited as a weak point. The [[Eclipse Scala plugin>>http://www.scala-ide.org]] has been found to be slow at times and sometimes buggy.
35	35
36	36	= WebObjects In Scala =
37	37
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44	44	Scala doesn't have static variables or methods. Instead Scala employs the [[Singleton Pattern>>http://en.wikipedia.org/wiki/Singleton_pattern]] which is built into the language and is **thread-safe**: a class can have a //Companion Object// that will allow you to achieve something equivalent to static variables - but better.
45	45
46	46	You don't have to worry about synchronizing access to shared mutable fields in a concurrent application.
47		-This is not however true for mutable ##val## e.g: ##NSMutableArray##, ##scala.collection.mutable.ListBuffer## which you will have to synchronize the adding to or removing from.
	47	+(This is not however true when for example you have a ##val## declared as a ##NSMutableArray##. You will still have to synchronize when adding to or removing from this mutable field).
48	48
49	49	The following is an example of the use of a //Companion Object// for Talent in Scala instead of Talent static fields in Java.
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61	61
62	62	{{code}}
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64		-object Talent extends EOGenericRecord {
	64	+object Talent {
65	65	val ENTITY_NAME = "Talent"
66	66
67	67	{{/code}}
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76	76
77	77	==== Compacted imports ====
78	78
79		-Two lines in Java are compacted into one in Scala.
80		-
81	81	In Java:
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83	83	{{code value="java"}}
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196	196
197	197	{{/code}}
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199		-After that, you may access the typical Scala collection methods directly on NSArray.  This employs a feature of Scala known as implicit conversions to automagically cast a NSArray (a Java Iterable) into a Scala Iterable while leaving the actual object unchanged.  Alternatively, you could generate an actual new scala.List instance by calling myNSArray.toList.
	197	+After that, you may access the typical Scala collection methods directly on NSArray.  This employs a feature of Scala known as implicit conversions to automagically cast a NSArray (a Java Iterable) into a Scala Iterable while leaving the actual object unchanged.
200	200
201		-== How to Add Scala to a WO Project ==
	199	+== How to Add Scala to a WO Project (in Eclipse) ==
202	202
203	203	{{include value="WOL:Adding Scala Support to a WOLips Project"}}{{/include}}
204	204
205		-{{note}}
206		-
207		-This is for Eclipse/WOLips IDE
208		-
209		-{{/note}}
210		-
211	211	== WO Scala Example ==
212	212
213	213	The following example is an almost 100% Scala WO app. In reality it is a mixed Java/Scala app: