Changes for page WebObjects with Scala

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1	1	=== What is Scala? ===
2	2
3		-Scala is a modern language not unlike Groovy.
4		-It is said to be more powerful (and faster) than Groovy or Ruby which has been the reason for its adoption at sites like Twitter.
	3	+Scala is a language for concurrent computing.
	4	+In the day and age of multi-core processors, concurrent computing can't be ignored.
5	5
6		-Many of its features and paradigms favor multi-threading and concurrency. Some of these may not be unfamiliar to Objective-C and WebObjects developers. Here's a summary:
	6	+Many of Scala's features have been designed with concurrency in mind.
	7	+Some of these may not be unfamiliar to Objective-C or WebObjects developers.
7	7
	9	+Here's a quick summary:
	10	+
8	8	|= |= Objective-C |= Java |= Scala
9	9	|= Mutable/Immuable Datatypes | Collections //e.g: NSArray/NSMutableArray// | No | Yes
10	10	|= Closures | Blocks (//Extension//) | No | Anonymous Functions
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23	23
24	24	=== Why Use Scala? ===
25	25
26		-With Web 2.0, building concurrent WebObjects applications is a must.
27	27	Developing and maintaining a concurrent or multi-threaded WebObjects application can be challenging.
28	28
29		-Scala offers concurrency that is (effectively) built-in to the language and is inherently thread-safe.
30		-In other words, developing Ajax (i.e asynchronous communication) with WO will require concurrent request handling and thread-safe code, for which Scala is a better choice than Java.
	31	+The lack of static variables means that Scala is inherently thread-safe.
	32	+It has concurrency that is effectively built-in to the language in the form of Actors.
31	31
32		-In addition it may offer new solutions for concurrency in WebObjects and EOF.
	34	+So for WebObjects developers, Scala offers itself as a powerful, safe and easy-to-use solution for concurrent applications.
	35	+(In other words, Scala can be used for problems that would normally have required threads).
33	33
34	34	=== Can WebObjects be Programmed In Scala? ===
35	35
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47	47	Scala doesn't have static variables or methods. However, a class can have a //Companion Object// that will allow you to achieve something equivalent to static variables.
48	48	One of the advantages of this approach is that it is **thread-safe**, so you don't have to worry about synchronizing access to these fields in a concurrent application.
49	49
50		-The following is an example of the use of a //Companion Object// for Talent in Scala instead of static fields in Java.
	53	+The following is an example of the use of a //Companion Object// for Talent in Scala instead of Talent static fields in Java.
51	51
52	52	Java:
53	53
54		-{{code}}
	57	+{{code value="java"}}
55	55
56	56	public class _Talent extends EOGenericRecord {
57	57	public static final String ENTITY_NAME = "Talent";
...	...	@@ -62,7 +62,7 @@
62	62
63	63	{{code}}
64	64
65		-object _Talent extends EOGenericRecord {
	68	+object Talent extends EOGenericRecord {
66	66	val ENTITY_NAME = "Talent"
67	67
68	68	{{/code}}
...	...	@@ -73,7 +73,7 @@
73	73
74	74	In Java:
75	75
76		-{{code}}
	79	+{{code value="java"}}
77	77
78	78	import com.webobjects.eocontrol.EOGenericRecord;
79	79	import com.webobjects.eocontrol.EORelationshipManipulation;
...	...	@@ -96,7 +96,7 @@
96	96
97	97	In Java:
98	98
99		-{{code}}
	102	+{{code value="java"}}
100	100
101	101	public class MenuHeader extends WOComponent {
102	102
...	...	@@ -121,7 +121,7 @@
121	121
122	122	In Java:
123	123
124		-{{code}}
	127	+{{code value="java"}}
125	125
126	126	try {
127	127	EditPageInterface epi = D2W.factory().editPageForNewObjectWithEntityNamed(_manipulatedEntityName, session());
...	...	@@ -155,6 +155,28 @@
155	155
156	156	{{/code}}
157	157
	161	+==== Scala Annotations vs. Generic Accessors ====
	162	+
	163	+An example of accessing variables in WebObjects with the following languages:
	164	+
	165	+|= |= Objective-C |= Java |= Scala
	166	+|= getter | ##object name## | ##object.name()## | ##object.name##
	167	+|= setter | ##object setName:aName## | ##object.setName(aName)## | ##object.name = aName##
	168	+
	169	+Of course in Java, we may generate WebObjects classes with "get" methods as well in order to stick to convention.
	170	+In scala there is an additional convenience we may use to produce "get" and "set" methods in addition to the default Scala accessors - Scala Annotations.
	171	+
	172	+E.g, in Main.scala we annotate our component keys with ##@BeanProperty## to automatically create public "set" and "get" methods.
	173	+These variables can then be accessed via //KVC//.
	174	+
	175	+{{code}}
	176	+
	177	+@BeanProperty var username = new String()
	178	+@BeanProperty var password = new String()
	179	+@BeanProperty var isAssistantCheckboxVisible = false
	180	+
	181	+{{/code}}
	182	+
158	158	== How to Use Scala Collections with EOF ==
159	159
160	160	One of the benefits of Scala is its very powerful, concurrency-ready collection classes - primarily ##List##, ##Map##, ##Seq## and ##Set##.
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206	206
207	207	1. Point to the local [[Scala versions>>http://wiki.objectstyle.org/confluence/display/WOL/EOGenerator+Templates+and+Additions]] of the .eotemplate files for ##Entity## and ##//Entity//##
208	208	1. Change the File Names Extension to "scala"
	234	+1. In Destination Paths set the Superclass Package (e.g: base)
209	209	1. Uncheck Java under Options
	236	+
	237	+== How to Build & Deploy a WebObjects Scala Project with Ant ==
	238	+
	239	+1. [[Download>>http://www.scala-lang.org/downloads]] and install Scala
	240	+1. Set ##scala.home## (the location Scala has been installed onto) in the project ##build.properties## file
	241	+1. [[Add the scalac task and properties>>Configuring Ant to Build Scala with WebObjects]] to the ant build.xml file
	242	+1. Run from the project directory: ##sudo ant clean install##