Wiki source code of WebObjects with Scala
Version 244.1 by Ravi Mendis on 2009/09/15 22:25
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21.1 | 1 | === What is Scala? === |
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195.1 | 2 | |
| 3 | Scala is a modern language not unlike Groovy. | ||
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209.1 | 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. |
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195.1 | 5 | |
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243.1 | 6 | Many of its features and paradigms favor multi-threaded and concurrent development which may not be unfamiliar to Objective-C developers: |
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195.1 | 7 | |
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241.1 | 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 | ||
| 14 | |= |= Weakly Typed |=--Strongly Typed--|= Strongly Typed | ||
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195.1 | 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 | |||
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241.1 | 29 | Scala offers concurrency that is (effectively) built-in to the language and is inherently thread-safe. |
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195.1 | 30 | So it may offer new solutions for concurrency in WebObjects. |
| 31 | |||
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239.1 | 32 | === Can WebObjects be Programmed In Scala? === |
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195.1 | 33 | |
| 34 | Yes. It is very simple. | ||
| 35 | Scala compiles to java bytecode. Hence using it with WebObjects is fairly straightforward. | ||
| 36 | |||
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239.1 | 37 | == How to Develop WebObjects In Scala == |
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195.1 | 38 | |
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231.1 | 39 | 1. [[Install the Scala eclipse IDE>>http://www.scala-lang.org/node/94]] |
| 40 | 1. Add Scala support to your WO project | ||
| 41 | 11. Right-click your project in the WO Explorer | ||
| 42 | 11. In the context menu select Scala -> Add Scala Nature | ||
| 43 | 1. Convert or use ##.scala## instead of ##.java## source | ||
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195.1 | 44 | |
| 45 | {{note title="Note"}} | ||
| 46 | |||
| 47 | This is for Eclipse/WOLips IDE | ||
| 48 | |||
| 49 | {{/note}} | ||
| 50 | |||
| 51 | == WO Scala Example == | ||
| 52 | |||
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205.1 | 53 | The following is a mixed Java/Scala version of the WO Movies D2W app. |
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195.1 | 54 | All the EO logic and WO components are in Scala. |
| 55 | Only the Application class is Java. | ||
| 56 | |||
| 57 | {{attachments patterns=".*zip"}}{{/attachments}} | ||
| 58 | |||
| 59 | === Setup === | ||
| 60 | |||
| 61 | 1. Install and run the OpenBase OBMovies database. | ||
| 62 | 1. Right-click on Application.java and run as a WOApplication (as usual). | ||
| 63 | |||
| 64 | ==== EO Templates ==== | ||
| 65 | |||
| 66 | See: [[Scala templates>>http://wiki.objectstyle.org/confluence/display/WOL/EOGenerator+Templates+and+Additions]] | ||
| 67 | |||
| 68 | When you create your ##.eogen## file, be sure to make the following changes in the EOGenerator Editor: | ||
| 69 | |||
| 70 | 1. Change the File Names Extension to "scala" | ||
| 71 | 1. Uncheck Java under Options |