Skip to Content

Wiki source code of WebObjects with Scala

Version 246.1 by Ravi Mendis on 2009/09/15 22:37
Show last authors
1 === What is Scala? ===
2
3 Scala is a modern language not unlike Groovy.
4 It is said to be more powerful (and faster) than Groovy or Rails which has been the reason for its adoption at sites like Twitter.
5
6 Many of its features and paradigms favor multi-threaded and concurrent development which may not be unfamiliar to Objective-C developers.
7 Here's a summary:
8
9 |= |= Objective-C |= Java |= Scala
10 |= Mutable/Immuable Datatypes | Collections //e.g: NSArray/NSMutableArray// | No | //All datatypes//
11 |= Closures | Blocks (//Extension//) | No | //Built-in//
12 |= Static variables | Yes | Yes | No
13 |= Static methods/functions | Yes | Yes | No
14 |= Concurrency | [[Grand Central Dispatch>>http://en.wikipedia.org/wiki/Grand_Central_Dispatch]] (//Extension//)| //Threads// | Actors
15 |= |= Weakly Typed |=--Strongly Typed--|= Strongly Typed
16
17 Other notable features include:
18
19 |= |= Objective-C |= Java |= Scala
20 |= Parametered methods | Yes //e.g: addObject: to~:// | No | Yes //e.g: add(object= ,to=)//
21 |= Class composition | Categories | Interfaces | Traits
22
23 A fuller description of Scala can be found [[here>>http://en.wikipedia.org/wiki/Scala_(programming_language)]].
24
25 === Why Use Scala? ===
26
27 With Web 2.0, building concurrent WebObjects applications is a must.
28 Developing and maintaining a concurrent or multi-threaded WebObjects application can be challenging.
29
30 Scala offers concurrency that is (effectively) built-in to the language and is inherently thread-safe.
31 So it may offer new solutions for concurrency in WebObjects.
32
33 === Can WebObjects be Programmed In Scala? ===
34
35 Yes. It is very simple.
36 Scala compiles to java bytecode. Hence using it with WebObjects is fairly straightforward.
37
38 == How to Develop WebObjects In Scala ==
39
40 1. [[Install the Scala eclipse IDE>>http://www.scala-lang.org/node/94]]
41 1. Add Scala support to your WO project
42 11. Right-click your project in the WO Explorer
43 11. In the context menu select Scala -> Add Scala Nature
44 1. Convert or use ##.scala## instead of ##.java## source
45
46 {{note title="Note"}}
47
48 This is for Eclipse/WOLips IDE
49
50 {{/note}}
51
52 == WO Scala Example ==
53
54 The following is a mixed Java/Scala version of the WO Movies D2W app.
55 All the EO logic and WO components are in Scala.
56 Only the Application class is Java.
57
58 {{attachments patterns=".*zip"}}{{/attachments}}
59
60 === Setup ===
61
62 1. Install and run the OpenBase OBMovies database.
63 1. Right-click on Application.java and run as a WOApplication (as usual).
64
65 ==== EO Templates ====
66
67 See: [[Scala templates>>http://wiki.objectstyle.org/confluence/display/WOL/EOGenerator+Templates+and+Additions]]
68
69 When you create your ##.eogen## file, be sure to make the following changes in the EOGenerator Editor:
70
71 1. Change the File Names Extension to "scala"
72 1. Uncheck Java under Options