Published on March 25, 2009
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. 1
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 quot;Irinyi 225quot;, University of Szeged Course is given by: » CAS Software AG, Karlsruhe; CAS Software Kft., Szeged » EclipseSource, Karlsruhe Contact: » Istvan Ballok, Balazs Brinkus 2
Goal of the course The goal of this course is to enable the attendants to create rich and interactive web 2.0 applications based on the Ajax framework: Eclipse Rich Ajax Platform (RAP). The course focuses on giving a thorough understanding of the underlying technologies and reserving ample time for hands-on exercises and tutorials, to transfer a pragmatic knowledge as well. Each lesson focuses on achieving a well defined goal, making one step forward in mastering the Eclipse Rich Ajax Platform. Review 3
1&1 » Part of United Internet » Products » Hosting » Market leader in Germany and UK, number 5 in USA » DSL » About 3 million DSL customers in Germany » Portal » Market leader in Germany Introduction 6
qooxdoo » RWT's native browser widget toolkit » qooxdoo is a framework of its own » Qooxdoo is more than what is used by RAP 7
Desktop like Applications in the Browser qooxdoo 9
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) qooxdoo 11
Architecture » Server based » Client based 12
Server Based » The RAP model » All user interface logic runs on the server Architecture 13
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 Architecture 14
Client Based » The qooxdoo model » User interface logic runs in the browser » Uses remote procedure calls (RPC) to communicate with the backend Architecture 15
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 Architecture 16
Workshop Building a temperature converter 1. Getting started 2. Tooling 3. OOP/TDD 4. Layout basics 5. Events 6. Theming 17
Getting Started » Installation » Building a qooxdoo skeleton application Workshop 18
Installation Getting Started 1. Install Python 1. Download the ActivePython 2.6 installer 2. Install ActivePython 3. Verify the Installation » Type python in the command shell 2. Install qooxdoo 1. Download the qooxdoo SDK 2. Unzip the qooxdoo SDK to C:/ Workshop 19
Build a qooxdoo Skeleton Getting Started » 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_workspacews_qooxdooconvert » Navigate to the project folder using the command line » and create a qooxdoo skeleton application » C:>cd C:_DEV_workspacews_qooxdooconvert » C:_DEV_workspacews_qooxdooconvert> c:qooxdoo-0.8.2-sdktoolbincreate-application.py -n convert » C:_DEV_workspacews_qooxdooconvert>cd convert » C:_DEV_workspacews_qooxdooconvertconvert> generate.py source » Refresh the project in Eclipse (F5) » Open the source/index.html in the Browser Workshop 20
Steps Getting Started Workshop 21
Unit Testing Tooling » Unit testing framework like JUnit » generate.py test » generate.py test-source Workshop 25
API documentation Tooling » Extract API documentation from source code » JavaDoc like comments in the code » Can be used for custom applications » generate.py api Workshop 26
Inspector Tooling » Navigate widget hierarchy » Modify widgets on the fly » Cross browser interactive console » generate.py inspector Workshop 27
Lint Tooling » 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 Workshop 28
Exercise Tooling » 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 Workshop 29
qooxdoo vs. Java OOP OOP Workshop 31
qooxdoo vs. Java OOP OOP » Inheritance » Properties » Automatically generate accessor and mutator methods » Optional change events on value changes Workshop 32
Summary OOP » 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 Workshop 33
Test Driven Development OOP » 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) Workshop 34
Exercise OOP 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 Workshop 35
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 Workshop 36
Widget Tree Widgets/Layout » All the widgets in a user interface are composed in a tree like structure » composite design pattern » each control can be added to a composite control » added using the parent's add method » Reparenting is possible (unlike in SWT) Workshop 37
Layout Manager Widgets/Layout » 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 calling setLayoutData on the child. Workshop 38
Grow Layout (1/5) Widgets/Layout » Simplest layout manager » All child widgets are stretched to the available size Workshop 39
Basic/Canvas Layout (2/5) Widgets/Layout » Absolute positioning » Canvas extends the functionality of Basic and supports » Percent sizes and coordinates » Attaching to the bottom and right edges Workshop 40
HBox/VBox (3/5) Widgets/Layout » places child widgets horizontally (HBox) or vertically (VBox) next to each other » Layout properties » flex to configure growing/shrinling » width respectivley height for percent sizes Workshop 41
Dock (4/5) Widgets/Layout » 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 Workshop 42
Grid (5/5) Widgets/Layout » Places widgets into a two dimensional grid » Each cell can contain at most one widget » Supports child widgets, which span several cells or columns » Layout properties » row, column » rowSpan, colSpan Workshop 43
Exercise - Temperature Converter UI Widgets/Layout 1. Create the class convert.Converter, which extends qx.ui.window.Window 2. Show this window by adding these lines to convert.Application: var converter = new convert.Converter(); converter.moveTo(50, 30); converter.open(); 3. Position the labels and text fiels into a grid. Workshop 44
Exercise - React on Text Input Events 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 the celsius property 4. Add changeValue event listeners to the celsius and fahrenheit input fields » Read the input field's value (.getValue()) » Convert it to a number (parseInt) » Call setFahrenheit/setCelsius with this value Workshop 46
Theming » Change the look & feel without changing the application code Workshop 47
Exercise - Appearance.js Theming Workshop 48
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! Workshop 49
License Licensed under Creative Commons Attribution Non-Commercial No Derivatives http://creativecommons.org/licenses/by-nc-nd/3.0/ 51
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