Software-Development with JavaScript and JooseHamburg, 22.Oktober 2008

No Agenda

Agenda

Joose isa meta object system for JavaScript

Joose is not

a browser/DOM/Ajax/Widget library like jQuery, Prototype, YUI,

Mootools or Dojo

Joose is not

a browser/DOM/Ajax/Widget library like jQuery, Prototype, YUI,

Mootools or Dojo You wil still very much need these when

you use Joose in the Browser

Joose helps

_ write

_ well structured,

_ expressive,

_ declarative,

_ maintainable

_ JavaScript applications.

Core Features

_ Classes

_ Interfaces

_ Mixins

_ Modules / Packages / Namespaces

_ Roles

_ (Mixins + Interfaces)

_ Method Modifiers

_ (think aspect oriented programming)

Core Features

Declarative methods to build all these things

Meta Features

Object based interface to introspect and manipulate all these things at

runtime.

Meta classes for classes, methods and attributes.

Meta?

Meta?

You don't need to understand the meta

features to work with Joose.

Meta?

You don't need to understand the meta

features to work with Joose.

But it is more fun if you do :)

Mission

Steal all the nice features from other programming languages.

Make them available in JavaScript in a way that feels native to JavaScript.

Java, C#, etc.

_ Classes

_ Interfaces

_ Packages / Namespaces

Smalltalk, CLOS (Common Lisp Object System)

_ Meta classes

_ Meta attributes

_ Meta methods

Ruby

_ Mixins

_ Meta classes

Perl 6

_ Roles

_ Method modifiers

_ Type constraints and coercions

Perl 5

_ Moose (All of the above)

LET‘S LOOK AT SOME CODE

a Class

Class("Point", {

})

with two attributes

Class("Point", { has: { x: {is: "ro"}, y: {is: "rw"}, }})

and a clear method

Class("Point", { has: { x: {is: "ro"}, y: {is: "rw"}, }, methods: { clear: function () { this.x = 0; this.setY(0); } }})

Inheritance

Class("Point3D", { isa: Point})

after...

Class("Point3D", { isa: Point, has: { z: {} }, after: { clear: function () { this.z = 0; } }})

before...

Class("Point3D", { isa: Point, has: { z: {} }, before: { clear: function () { this.z = 0; } }})

before...

Class("Point3D", { isa: Point, has: { z: {} }, override: { clear: function () { this.SUPER(); this.z = 0; } }})

Usage

var point = new Point3D();

point.setX(10);

var y = point.getY(10);

point.z = 1;

point.clear();

var point2 = new Point3D({ x: 10, y: 20 });

Modules

_ create a namespace

_ create a lexical scope for your code.

_ No need for ugly

_ (function () { ... })()

Bank.Account

Module("Bank", function (m) { Class("Account", { has: { balance: { is: "rw", init: 0 } } }})

JSON Integration

Class("Geometry.Point", { does: Joose.Storage, has: { x: {is: rw}, y: {is: rw}, $: { is: rw, init: "stuff", persistent: false } }})

JSON Integration

var p = new Geometry.Point({x: 10, y: 20}) var jsonSring = JSON.stringify(p); var p2 = JSON.parse(jsonString); alert(p2.getX())

JSON Integration

var p = new Geometry.Point({x: 10, y: 20}) var jsonSring = JSON.stringify(p); var p2 = JSON.parse(jsonString); alert(p2.getX())

Turn Joose Objects into JSON and turn JSON

into Joose objects

JSON Integration

var p = new Geometry.Point({x: 10, y: 20}) var jsonSring = JSON.stringify(p); var p2 = JSON.parse(jsonString); alert(p2.getX())

Turn Joose Objects into JSON and turn JSON

into Joose objects

Backend Integration!

Total JavaScript Makeover!

Classes and Namespaces in native JSif(Test == null) { Test = {};}

Test.StandardPoint = function (x, y) { this.x = x || 0 this.y = y || 0}

Test.StandardPoint.prototype = { getX: function () { return this.x }, setX: function (x) { this.x = x }, getY: function () { return this.y }, setY: function (y) { this.y = y; }, clear: function () { this.setX(0) this.setY(0) }}

Dramatization

Classes and Namespaces in native JS

if(Test == null) { Test = {};}

Test.StandardPoint = function (x, y) { this.x = x || 0 this.y = y || 0}

Test.StandardPoint.prototype = { getX: function () { return this.x }, setX: function (x) { this.x = x }, getY: function () { return this.y }, setY: function (y) { this.y = y; }, clear: function () { this.setX(0) this.setY(0) }}

Dramatization

Using Joose

Module("Test", function (m) { Class("Point", { has: { x: { is: "rw", init: 0 }, y: { is: "rw", init: 0 } }, methods: { clear: function () { this.setX(0); this.setY(0); } } })})

Using Joose

Module("Test", function (m) { Class("Point", { has: { x: { is: "rw", init: 0 }, y: { is: "rw", init: 0 } }, methods: { clear: function () { this.setX(0); this.setY(0); } } })})

No need for scrolling!

Class inheritance and method wrappers in native JS// We need a utility function to do the inheritancefunction inherit(superClass, subClass) { for(var i in superClass.prototype) { subClass.prototype[i] = superClass.prototype[i] }}

Test.StandardPoint3D = function (x, y, z) { this.x = x || 0 this.y = y || 0 this.z = z || 0}

// Make Test.Standard the super class of Test.StandardPoint3Dinherit(Test.StandardPoint, Test.StandardPoint3D)

// we cant assign a new prototype because we already have the one from the superTest.StandardPoint3D.prototype.getZ = function () { return this.z}

Test.StandardPoint3D.prototype.setZ = function (z) { this.z = z;}

var superMethod = Test.StandardPoint3D.prototype.clear;Test.StandardPoint3D.prototype.clear = function () { superMethod.apply(this); this.z = 0;}

Dramatization

Class inheritance and method wrappers in native JS

// We need a utility function to do the inheritancefunction inherit(superClass, subClass) { for(var i in superClass.prototype) { subClass.prototype[i] = superClass.prototype[i] }}

Test.StandardPoint3D = function (x, y, z) { this.x = x || 0 this.y = y || 0 this.z = z || 0}

// Make Test.Standard the super class of Test.StandardPoint3Dinherit(Test.StandardPoint, Test.StandardPoint3D)

// we cant assign a new prototype because we already have the one from the superTest.StandardPoint3D.prototype.getZ = function () { return this.z}

Test.StandardPoint3D.prototype.setZ = function (z) { this.z = z;}

var superMethod = Test.StandardPoint3D.prototype.clear;Test.StandardPoint3D.prototype.clear = function () { superMethod.apply(this); this.z = 0;}

Dramatization

Using Joose

Module("Test", function (m) { Class("Point3D", { isa: m.Point, has: { z: { is: "rw", init: 0 } }, after: { clear: function () { this.setZ(0) } } })})

EXAMPLES

Class Browser

_ http://it.test.avantaxx.de/xssinterface/projects/Joose/examples/class_browser.html

blok

_ http://blok.appspot.com

_ http://code.google.com/p/joose-js/source/browse/trunk/examples/blok/block/ui/Element.js

_ http://code.google.com/p/joose-js/source/browse/trunk/examples/blok/block/ui/role/Focusable.js

_ http://code.google.com/p/joose-js/source/browse/trunk/examples/blok/block/ui/role/Resizable.js

File Size

_ Minified: 56 kb

_ GZipped: 16 kb

Speed

Should be fine if you're not building a canvas based ray tracer for real time

animations.

Profiling shows that Joose's overhead is negligible in most real world

applications.

Speed

Should be fine if you're not building a canvas based ray tracer for real time

animations.

Profiling shows that Joose's overhead is negligible in most real world

applications.

Tell me if you do, though!

Other Frameworks

_ Integration with jQuery works like a charm

_ YUI should be fine, too (Because YUI is very serious about namespaces).

_ Others should be fine as well

Joose does not

_ extend any default object prototypes.

Object.prototype.boom = function () {

alert(„Dont try this at home“)

}

Joose runs

_ in all common browsers

_ Rhino

_ JScript.NET

_ Flash comming soon

_ Ensured by an extensive automated test suite.

Joose runs

_ in all common browsers

_ Rhino

_ JScript.NET

_ Flash comming soon

_ Ensured by an extensive automated test suite.

No extra testing in IE6 required :)

Use cases?

Joose is not always the right tool for the job!

Use it if

You need more than three "classes".

It makes sense to maintain page state in objects.

Advanced Topics

_ Backend Integration

_ Prototype based object orientation

_ Everything Meta

_ DOM Binding

_ Client Side Databases

More Info

_ http://code.google.com/p/joose-js/

_ http://joose-js.blogspot.com

Thank You