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Developing web applications with Eclipse RAP Technology

Lecture 08 - Qooxdoo

This presentation is given by

» Fabian Jakobs (1&1)

» Balazs Brinkus

» Istvan Ballok

Date: 23.3.2009.

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Review

General information on the Eclipse RAP Course

Title: Developing web applications with Eclipse RAP technology

Time frame: Spring Semester, 2009 (February - May) (14 lessons)

Schedule: Mondays, 14-16, Room "Irinyi 225", University of Szeged

Course is given by:

» CAS Software AG, Karlsruhe; CAS Software Kft., Szeged

» EclipseSource, Karlsruhe

Contact:

» Istvan Ballok, Balazs Brinkus

3Review

Goal of the course

The goal of this course is to enable the attendants to create rich andinteractive web 2.0 applications based on the Ajax framework: EclipseRich Ajax Platform (RAP).

The course focuses on giving a thorough understanding of theunderlying technologies and reserving ample time for hands-onexercises and tutorials, to transfer a pragmatic knowledge as well.

Each lesson focuses on achieving a well defined goal, making one stepforward in mastering the Eclipse Rich Ajax Platform.

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Contents of this lecture - Qooxdoo

8 23.3. Create a standalone qooxdoo application

» Introduction» Fabian Jakobs, 1&1

» qooxdoo

» Architecture» Server based

» Client based

» Workshop» JavaScript basics

» Getting started

» Tooling

» OOP/TDD

» Layout basics

» Events

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Introduction

Fabian Jakobs» fabian.jakobs@1und1.de

» JavaScript framework developer at 1&1

» Working on qooxdoo since 2006

» Diploma of Computer Science at the UniversityKarlsruhe 2006

6Introduction

1&1

» Part of United Internet

» Products» Hosting

» Market leader in Germanyand UK, number 5 in USA

» DSL» About 3 million DSL

customers in Germany

» Portal» Market leader in Germany

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qooxdoo

» RWT's native browser widget toolkit

» qooxdoo is a framework of its own

» Qooxdoo is more than what is used by RAP

8qooxdoo

Pure JavaScript Widget Toolkit like SWT

9qooxdoo

Desktop like Applications in the Browser

10qooxdoo

History

» qooxdoo 0.1 (May 2005)» Released as open source (LGPL) hosted on Sourceforge

» qooxdoo 0.5 (February 2006)» First modern widget toolkit

» qooxdoo 0.6 (September 2006)» Addition of the Table widget and RPC client

» Introduction of name spaces

» qooxdoo 0.7 (June 2007)» Introduced new JavaScript OOP system

» Dual licenced LGPL/EPL due to integration into RAP

» qooxdoo 0.8 (August 2008)» Rewrite of the layout/widget system

» New build system

11qooxdoo

qooxdoo 0.7 versus qooxdoo 0.8

» RAP still uses qooxdoo 0.7

» This lecture will cover 0.8

» qooxdoo 0.8 is not API compatible to 0.7

» Differences» Layout managers work differently

» Core widget API changed

» Theming

» Unchanged» qooxdoo OO syntax

» Collection of widgets

» The public API of specific widgets (e.g. Table)

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Architecture

» Server based

» Client based

13Architecture

Server Based

» The RAP model

» All user interface logic runs on the server

14Architecture

Server Based

» Advantages» (+) Backend communication is trivial

» (+) Secure

» (+) Same Programming language as for the business logic

» (+) Possibility to build native clients from the same code base

» Disadvantages» (-) Hard to react on high frequency user events (e.g. mouse move)

» (-) Hard to extend with custom widgets

» (-) No offline mode possible

15Architecture

Client Based

» The qooxdoo model

» User interface logic runs in the browser

» Uses remote procedure calls (RPC) to communicate with thebackend

16Architecture

Client Based

» Advantages» (+) User interaction events can be handled locally

» (+) It's possible to leverage special browser features

» (+) Offline support possible

» (+) Easy to write custom widgets

» Disadvantages» (-) Backends expose functionality as remote services

» (-) Remote services must be secured

» (-) Different technology stack on backend and frontend

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Workshop

Building a temperature converter1. Getting started

2. Tooling

3. OOP/TDD

4. Layout basics

5. Events

6. Theming

18Workshop

Getting Started

» Installation

» Building a qooxdoo skeleton application

19Workshop

Getting Started Installation

1. Install Python1. Download the ActivePython 2.6 installer

2. Install ActivePython

3. Verify the Installation» Type python in the command shell

2. Install qooxdoo1. Download the qooxdoo SDK

2. Unzip the qooxdoo SDK to C:/

20Workshop

Getting Started Build a qooxdoo Skeleton

» Create a new project in the Eclipse Workspace» File / New / Other.. / General - Project

» Name of the project: convert

» copy the location of the project resource from the project properties» e.g. C:\_DEV_\workspace\ws_qooxdoo\convert

» Navigate to the project folder using the command line» and create a qooxdoo skeleton application

» C:\>cd C:\_DEV_\workspace\ws_qooxdoo\convert

» C:\_DEV_\workspace\ws_qooxdoo\convert>c:\qooxdoo-0.8.2-sdk\tool\bin\create-application.py-n convert

» C:\_DEV_\workspace\ws_qooxdoo\convert>cd convert

» C:\_DEV_\workspace\ws_qooxdoo\convert\convert>generate.py source

» Refresh the project in Eclipse (F5)» Open the source/index.html in the Browser

21Workshop

Getting Started Steps

22Workshop

Tooling

» When we started nearly no tools existed» But tools are necessary for professional development

» We had to build our own

» qooxdoo JavaScript tools» Linker

» Optimizer/Packer

» Unit testing

» API documentation

» Inspector

» Lint

» Third party tools» FireBug

» Safari Web Inspector

» Opera Dragonfly

» IE8 Developer Toolbar

23Workshop

Tooling Linker

» Detect dependencies between JavaScript files

» Sorted list of files to include

» Essential for large applications

» generate.py source, generate.py build

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Tooling Optimizer/Packer

» Combine JavaScript files

» Optimize/obfuscate JavaScript

» generate.py build

25Workshop

Tooling Unit Testing

» Unit testing framework like JUnit

» generate.py test

» generate.py test-source

26Workshop

Tooling API documentation

» Extract API documentation from source code

» JavaDoc like comments in the code

» Can be used for custom applications

» generate.py api

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Tooling Inspector

» Navigate widget hierarchy

» Modify widgets on the fly

» Cross browser interactive console

» generate.py inspector

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Tooling Lint

» Static code analysis» Find common coding mistakes

» Enforce coding guidelines

» Especially useful in dynamic languages, where errors» Often occur only at runtime

» Only under certain conditions

» Have strange side effects and are hard to find

» Finds e.g.» Undefined variables

» Unused variables

» Redefnition of map keys

» generate.py lint

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Tooling Exercise

» Run these jobs and check the results

Command Result

generate.py source source/index.html

generate.py test test/index.html

generate.py test-source test/index-source.html

generate.py api api/index.html

generate.py inspector source/inspector.html

generate.py lint (output in the console)

generate.py build build/index.html

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OOP

» JavaScript provides only basic OOP features» Prototype based inheritance

» No interfaces

» calling overridden methods in super classes is hard

» ...

» The language is flexible enough to create a meta OO model on top

» This is what most JavaScript frameworks do

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OOP qooxdoo vs. Java OOP

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OOP qooxdoo vs. Java OOP

» Inheritance

» Properties» Automatically generate accessor and mutator methods

» Optional change events on value changes

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OOP Summary

» qooxdoo supports most of Java's OOP features» Classes

» Interfaces

» Namespaces

» Calling overridden methods in base classes

» Conventions for access control

» Additional OO features» Dynamic properties

» Mixins» Add functionality to existing classes

» Concept used in Objective-C, Ruby, Python

» Unsupported Java OO features» Method/constructor overloading

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OOP Test Driven Development

» Principles» Don't write production code unless it makes a failing test pass

» Don't write more unit tests than is sufficient to fail

» Don't write more production code than is sufficient to pass the failing test

» TDD in qooxdoo» qx.dev.unit.TestCase is the base class for all test cases

» Test methods are instance methods with a test prefix

» The TestCase class provides a collection of assertion methods (e.g.assertEquals)

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OOP Exercise

1. Write the test» Write the class convert.test.TemperatureUtil, which

extends qx.dev.unit.TestCase

» Write a unit test for celsiusToFahrenheit.» Known values: 100°C = 212°F, 0°C = 32°F, -17.78°C = 0°F

» Run the test and see it fail

2. Implement the conversion» Write the static class convert.TemperatureUtil

» Write the static method celsiusToFahrenheit» Formula: fahrenheit = (celsius * 1.8) + 32;

» Run the test and see it pass

3. Write test and implementation for fahrenheitToCelsius

36Workshop

Widgets/Layout

Widget Types» Basic widget

» Widget, Image, Label, Atom

» Form widgets» Button, TextField, CheckBox, ComboBox, ...

» Container widget» Window, GroupBox, Composite, SplitPane, ...

» Complex widgets» Table, Tree, List

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Widgets/Layout Widget Tree

» All the widgets in a user interfaceare composed in a tree likestructure

» composite design pattern

» each control can be added to acomposite control

» added using the parent's addmethod

» Reparenting is possible (unlike inSWT)

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Widgets/Layout Layout Manager

» Very similar to SWT

» a Layout Manager is assigned to the parent

» corresponding Layout Data can be assigned to each child widget,to control the layouting process

» can be set as the second parameter of the parent's add method or by callingsetLayoutData on the child.

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Widgets/Layout Grow Layout (1/5)

» Simplest layout manager

» All child widgets are stretched to the available size

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Widgets/Layout Basic/Canvas Layout (2/5)

» Absolute positioning

» Canvas extends thefunctionality of Basic andsupports

» Percent sizes and coordinates

» Attaching to the bottom andright edges

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Widgets/Layout HBox/VBox (3/5)

» places child widgets horizontally (HBox) or vertically (VBox) next toeach other

» Layout properties» flex to configure growing/shrinling

» width respectivley height for percent sizes

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Widgets/Layout Dock (4/5)

» Docks children to one of the parent's edges

» Layout properties» edge - one of north, east, south, west or center

» width optional percent width

» height optional percent height

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Widgets/Layout Grid (5/5)

» Places widgets into a twodimensional grid

» Each cell can contain at mostone widget

» Supports child widgets, whichspan several cells or columns

» Layout properties» row, column

» rowSpan, colSpan

44Workshop

Widgets/Layout Exercise - Temperature Converter UI

1. Create the classconvert.Converter, whichextendsqx.ui.window.Window

2. Show this window by addingthese lines toconvert.Application:

var converter = new convert.Converter();converter.moveTo(50, 30);converter.open();

3. Position the labels and text fiels into a grid.

45Workshop

Events

» User interaction result in events

» Events can be handled by using event listeners» in JavaScript/qooxdoo

» in Java/SWT

» Event types» mouse

» keyboard

» focus

» selection

» execute

» ...

46Workshop

Events Exercise - React on Text Input

1. Add a property celsius. This is the reference temperature

2. Add getFahrenheit, which returns the converted celsius value

3. Add setFahrenheit, which stores the converted value in thecelsius property

4. Add changeValue event listeners to the celsius and fahrenheitinput fields

» Read the input field's value (.getValue())

» Convert it to a number (parseInt)

» Call setFahrenheit/setCelsius with this value

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Theming

» Change the look & feel without changing the application code

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Theming Exercise - Appearance.js

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Possible Improvements

» Error handling if user enters an invalid number

» Use localized number formatter and parser

» Use spinner widgets

» ...

Be creative - Play with the code!

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Resources

» qooxdoo» Online manual

» API viewer

» Demo browser

» JavaScript» "JavaScript: The Good Parts: Working with the Shallow Grain of JavaScript"

by Douglas Crockford

» "JavaScript. The Definitive Guide" by David Flanagan

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License

Licensed under Creative CommonsAttribution Non-Commercial No Derivatives

http://creativecommons.org/licenses/by-nc-nd/3.0/