WebObjects with Scala

=== What is Scala? ===

Scala is a modern language not unlike Groovy.

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 and WebObjects developers. Here's a summary:

7

8

|= |= Objective-C |= Java |= Scala

9

|= Mutable/Immuable Datatypes | Collections //e.g: NSArray/NSMutableArray// | No | //All datatypes//

10

|= Closures | Blocks (//Extension//) | No | //Built-in//

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

15

16

Other notable features include:

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

22

A fuller description of Scala can be found [[here>>http://en.wikipedia.org/wiki/Scala_(programming_language)]].

23

24

=== Why Use Scala? ===

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.

28

29

Scala offers concurrency that is (effectively) built-in to the language and is inherently thread-safe.

30

So it may offer new solutions for concurrency in WebObjects.

31

32

=== Can WebObjects be Programmed In Scala? ===

33

34

Yes. It is very simple.

35

Scala compiles to java bytecode. Hence using it with WebObjects is fairly straightforward.

36

37

= WebObjects In Scala =

38

39

The following is an in-depth explanation of differences between Java and Scala in WebObjects:

== EOs in Scala ==

=== Constants ===

Scala doesn't have static variables or methods. However, every class does have a //Companion Object// that will allow you to achieve something equivalent to static variables.

46

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.

In Java:

public class _Talent extends EOGenericRecord {

53

public static final String ENTITY_NAME = "Talent";

54

55