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>>http://en.wikipedia.org/wiki/Scala_(programming_language)]] is a language for concurrent computing.
	4	+In this 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
8		-|= |= Objective-C |= Java |= Scala
9		-|= Mutable/Immuable Datatypes | Collections //e.g: NSArray/NSMutableArray// | No | Yes
10		-|= Closures | Blocks (//Extension//) | No | Anonymous Functions
11		-|= Static variables | Yes | Yes | No
12		-|= Static methods/functions | Yes | Yes | No
13		-|= Concurrency | [[Grand Central Dispatch>>http://en.wikipedia.org/wiki/Grand_Central_Dispatch]] (//Extension//)| //Threads// |[[Actors>>http://en.wikipedia.org/wiki/Actor_model]]
14		-|= |= Weakly Typed |=--Strongly Typed--|= Strongly Typed
	9	+Here's a quick summary:
15	15
	11	+|= |= Objective-C |= Java |= Scala
	12	+|= Separation of Mutable & Immuable Datatypes | Collections //e.g: NSArray/NSMutableArray// | No | Yes
	13	+|= Closures | Blocks (//Extension//) | No | Anonymous Functions
	14	+|= Static variables | Yes | Yes | No
	15	+|= Static methods or functions | Yes | Yes | No
	16	+|= Concurrency | [[Grand Central Dispatch>>http://en.wikipedia.org/wiki/Grand_Central_Dispatch]] (//Extension//)| //Threads// |[[Actors>>http://en.wikipedia.org/wiki/Actor_model]]
	17	+|= |= Weakly Typed |=--Strongly Typed--|= Strongly Typed
	18	+
16	16	Other notable features include:
17	17
18		-|= |= Objective-C |= Java |= Scala
19		-|= Parametered methods | Yes //e.g: addObject: to~:// | No | Yes //e.g: add(object= ,to=)//
20		-|= Class composition | Categories | Interfaces | Traits
	21	+|= |= Objective-C |= Java |= Scala
	22	+|= Parametered methods | Yes //e.g: addObject: to~:// | No | Yes //e.g: add(object= ,to=)//
	23	+|= Class composition | Categories | Interfaces | Traits
21	21
22		-A fuller description of Scala can be found [[here>>http://en.wikipedia.org/wiki/Scala_(programming_language)]].
23		-
24	24	=== Why Use Scala? ===
25	25
26		-With Web 2.0, building concurrent WebObjects applications is a must.
27		-Developing and maintaining a concurrent or multi-threaded WebObjects application can be challenging.
	27	+Scala is inherently thread-safe.
	28	+It has concurrency that is effectively built-in to the language.
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.
	30	+So for WebObjects developers, Scala offers itself as a powerful, safe and easy-to-use solution for [[concurrent applications>>Building Concurrent Applications with WebObjects and Scala]]. (In other words, Scala Actors can be used for problems that would have normally required threads).
31	31
32		-In addition it may offer new solutions for concurrency in WebObjects and EOF.
33		-
34	34	=== Can WebObjects be Programmed In Scala? ===
35	35
36	36	Yes. It is very simple.
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51	51
52	52	Java:
53	53
54		-{{code}}
	52	+{{code value="java"}}
55	55
56	56	public class _Talent extends EOGenericRecord {
57	57	public static final String ENTITY_NAME = "Talent";
...	...	@@ -73,7 +73,7 @@
73	73
74	74	In Java:
75	75
76		-{{code}}
	74	+{{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}}
	97	+{{code value="java"}}
100	100
101	101	public class MenuHeader extends WOComponent {
102	102
...	...	@@ -117,11 +117,11 @@
117	117	==== Simplified Exception Handling ====
118	118
119	119	Scala doesn't force you to catch exceptions unlike in Java.
120		-In addition, the syntax employs Scala's very powerful pattern matching to handle different exceptions.
	118	+In addition, the syntax employs Scala's very powerful **pattern matching** to handle exceptions.
121	121
122	122	In Java:
123	123
124		-{{code}}
	122	+{{code value="java"}}
125	125
126	126	try {
127	127	EditPageInterface epi = D2W.factory().editPageForNewObjectWithEntityNamed(_manipulatedEntityName, session());
...	...	@@ -155,7 +155,7 @@
155	155
156	156	{{/code}}
157	157
158		-==== Scala Annotations vs. Generic Accessors ====
	156	+==== Scala Annotations vs. Generated Accessors ====
159	159
160	160	An example of accessing variables in WebObjects with the following languages:
161	161
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171	171
172	172	{{code}}
173	173
	172	+import scala.reflect.BeanProperty
	173	+
174	174	@BeanProperty var username = new String()
175	175	@BeanProperty var password = new String()
176	176	@BeanProperty var isAssistantCheckboxVisible = false
...	...	@@ -179,7 +179,7 @@
179	179
180	180	== How to Use Scala Collections with EOF ==
181	181
182		-One of the benefits of Scala is its very powerful, concurrency-ready collection classes - primarily ##List##, ##Map##, ##Seq## and ##Set##.
	182	+One of the benefits of Scala is its very powerful, concurrency-ready collection classes - primarily ##List##, ##Map## and ##Set##.
183	183	Employing these instead of ##NSArray## and ##NSDictionary## in WebObjects/EOF may be challenging.
184	184
185	185	But one may modify the EO templates to produce API such as:
...	...	@@ -186,11 +186,11 @@
186	186
187	187	{{code}}
188	188
189		-def movies: NSArray[EOGenericRecord] = {
190		- storedValueForKey(_Studio.Keys.MOVIES).asInstanceOf[NSArray[EOGenericRecord]]
	189	+def movies: NSArray[Studio] = {
	190	+ storedValueForKey(_Studio.Keys.MOVIES).asInstanceOf[NSArray[Studio]]
191	191	}
192	192
193		-def moviesList: List[EOGenericRecord] = {
	193	+def moviesList: List[Studio] = {
194	194	movies.objects.toList
195	195	}
196	196
...	...	@@ -200,7 +200,7 @@
200	200
201	201	{{include value="WOL:Adding Scala Support to a WOLips Project"}}{{/include}}
202	202
203		-{{note title="Note"}}
	203	+{{note}}
204	204
205	205	This is for Eclipse/WOLips IDE
206	206
...	...	@@ -233,7 +233,15 @@
233	233
234	234	== How to Build & Deploy a WebObjects Scala Project with Ant ==
235	235
236		-1. Download an install Scala
237		-1. The ##scala.home## (the location Scala has been installed onto) to the project ##build.properties## file
238		-1. Add the ##scalac## tasks to the ant build.xml file
239		-1. Customise the app classpath file. i.e either ##MacOSClasspath.txt## or ##UNIXClasspath.txt##. You will need to add an entry for ##scala-library.jar##
	236	+1. [[Download>>http://www.scala-lang.org/downloads]] and install Scala
	237	+1. Set ##scala.home## (the location Scala has been installed onto) in the project ##build.properties## file
	238	+1. [[Add the scalac task and properties>>Configuring Ant to Build Scala with WebObjects]] to the ant build.xml file
	239	+1. Run from the project directory: ##sudo ant clean install##
	240	+
	241	+== Caveats ==
	242	+
	243	+{{warning}}
	244	+
	245	+Currently mixed Scala and Java projects aren't supported by the Scala Eclipse IDE, though it is possible to do so providing your project is either mostly Java or mostly Scala.
	246	+
	247	+{{/warning}}