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Changes for page WebObjects with Scala

Last modified by Ravi Mendis on 2011/05/10 02:10
From version 392.1
edited by Ravi Mendis
on 2009/12/15 18:10
Change comment: There is no comment for this version
To version 394.1
edited by Ravi Mendis
on 2010/01/17 22:10
Change comment: There is no comment for this version

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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 -Developing and maintaining a concurrent or multi-threaded WebObjects application can be challenging.
29 +Scala is inherently thread-safe.
30 +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.
32 +So for WebObjects developers, Scala offers itself as a powerful, safe and easy-to-use solution for concurrent applications. (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}}
54 +{{code value="java"}}
55 55  
56 56  public class _Talent extends EOGenericRecord {
57 57   public static final String ENTITY_NAME = "Talent";
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73 73  
74 74  In Java:
75 75  
76 -{{code}}
76 +{{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}}
99 +{{code value="java"}}
100 100  
101 101  public class MenuHeader extends WOComponent {
102 102  
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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.
120 +In addition, the syntax employs Scala's very powerful **pattern matching** to handle exceptions.
121 121  
122 122  In Java:
123 123  
124 -{{code}}
124 +{{code value="java"}}
125 125  
126 126  try {
127 127   EditPageInterface epi = D2W.factory().editPageForNewObjectWithEntityNamed(_manipulatedEntityName, session());
... ... @@ -234,6 +234,6 @@
234 234  == How to Build & Deploy a WebObjects Scala Project with Ant ==
235 235  
236 236  1. [[Download>>http://www.scala-lang.org/downloads]] and 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##
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##