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Difference between revisions of "EMF/Databinding in an RCP Application"

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This document was converted from PDF using pdftohtml-0.36-145.7.i586.rpm, then to wiki markup using [http://diberri.dyndns.org/wikipedia/html2wiki/ html2wiki]. See also {{bug|195163}}.
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[[Category:EMF]]
 
[[Category:EMF]]

Revision as of 13:41, 8 July 2008

Abstract/Requirements Definition

I'm trying to implement a fairly simple address book application on top of RCP using frameworks provided by Eclipse in 3.3. There's also focus on how to structure and design an RCP to be as extensible and as flexible as possible, including theming, internationalization, datastorage independency, etc.

Setup the Toolchain

1. Eclipse 3.3 for RCP-Developers (available from http://www.eclipse.org/downloads)

2. EMF using the Update-Manager (Help>Software Updates>Find and Install)

3. Derby-Plugins (available from http://db.apache.org/derby/derby_downloads.html)

To install:

1. Stop your eclipse (if running)

2. Unzip "derby.zip"s (as of this writing derby_core_plugin_10.2.2.485682.zip and derby_ui_plugin_1.1.0.zip) into your %ECLIPSE_HOME/plugin directory

3. Start up eclipse

4. iBatis (available from http://ibatis.apache.org)

5. Fetch application icons (e.g. available from http://websvn.kde.org/trunk/KDE/kdelibs/pics/oxygen/ using your favorite SVN Client)

6. (Optional) Visual-Database Design

1. Install Clay for Eclipse (available from http://www.azzurri.jp/en/software/clay/)

2. Download Clay-Utils used for creation of DDL and documentation (available from http://publicsvn.bestsolution.at/repos/java/clayUtils/release/at.bestsolution.clayutils-nodeps-0.0.7.jar)

3. DDL-Utils to create database DDL for any database you want (available from http://db.apache.org/ddlutils)

7. (Optional) Subclipse for Version-Control (available from http://subclipse.tigris.org)

Application Design

Plugin Design

at.bestsolution.addressbook

The main RCP Application

at.bestsolution.addressbook.ui

This plugin provides the UI bits (ViewPart, ...) for the addressbook application.



at.bestsolution.addressbook.ui.theme

This plugin addresses the themeability of the application by providing a plugable theme-

API. It will by default provide a standard theme.

at.bestsolution.addressbook.core

This plugin provides the none GUI bits for the application like Command-Definitions,

handlers, ...

at.bestsolution.addressbook.core. model

This plugin provides the model implementation created using EMF

at.bestsolution.addressbook.core.datasource

This plugin will provide the API to provide plugable datasources in our case

at.bestsolution.addressbook.core.datasource.xmi

This plugin provides a datasource implementation on top of XMI (directly supported by EMF)

at.bestsolution.addressbook.core.datasource.iBatis

This plugin provides a datasource implementation on top of iBatis

Plugin Overview

Domainmodel

The domain model is fairly simple and can be represented by 2 classes as shown in the diagram below. The only interesting thing is that there's a bidirectional relationship between Person(Attribute: primaryAddress) and Address(Attribute: person).



File:Emf-article-3 1.jpg

Hands on practice or "Let's begin our journey"

Implementing at.bestsolution.addressbook.core. model

Create an EMF- Project

1. Select Eclipse Modeling Framework

2. Name the project "at.bestsolution.addressbook.core.model"



File:Emf-article-4 1.jpg

3. The resulting workspace looks like this

Create the Ecore- Model

1. Select Example EMF Model Creation Wizards > Ecore Model



2. Name the model "addressbook.ecore"



File:Emf-article-6 1.jpg

File:Emf-article-6 2.jpg

3. Open the Properties-View (Window > Show View > Others ...)

4. Select the root node currently shown in the editor as null



5. Editing the properties in the property view

Now we have to add our Domain-Objects Person and Address to the Ecore-Model.

1. Right click on the addressbook-package you have created above and select

"New Child > EClass"

2. Set the following properties (in the Properties View)

Name: Person

3. Right click the Person and select "New Child > EAttribute"

4. Set the following properties (in the Properties View)

Name: surname

EType: Estring

5. Right click the Person and select "New Child > EAttribute"

6. Set the following properties (in the Properties View)

Name: givenname

EType: Estring

7. Right click the Person and select "New Child > EAttribute"

8. Set the following properties (in the Properties View)

Name: birthday

EType: Edate

9. Right click on the addressbook-package you have created above and select

"New Child > EClass"

10. Set the following properties (in the Properties View)

Name: Address

11. Right click the Address and select "New Child > EAttribute"



12. Set the following properties (in the Properties View)

Name: street

EType: Estring

13. Right click the Address and select "New Child > EAttribute"

14. Set the following properties (in the Properties View)

Name: zip

EType: Estring

15. Right click the Address and select "New Child > EAttribute"

16. Set the following properties (in the Properties View)

Name: city

EType: Estring

17. Right click the Address and select "New Child > EAttribute"

18. Set the following properties (in the Properties View)

Name: country

EType: Estring

After having done this your model should look like the following:

Next thing we have to model is the bidirectional relation between Person and Address

like we defined it in our UML-Class Diagramm.

1. Right click the Person and select "New Child > EReference"

2. Set the following properties (in the Properties View)

Name: primaryAddress

EType: Address

Containment: true

3. Right click the Address and select "New Child > EReference"



4. Set the following properties (in the Properties View)

Name: person

EType: Person

EOpposite: primaryAddress

Transient: true

The Ecore model should look like this now:

At this point we have implemented our original Domain-Model in Ecore but we are not finished because when we are working with Jface' Databinding Framework that ships with 3.3 we need to follow the JavaBean specification which means our domain objects have to implement java.bean.PropertyChangeSupport.

The best way to model this is that all our Domain-Model-Objects inherit from a super-class named BaseObject.

Because there are no wrapper for the Classes and Interfaces needed to implement PropertyChangeSupport and friends we need to create them our own by defining "EData

Types":

1. Right click on the addressbook-package you have created above and select

"New Child > EData Type"

2. Set the following properties (in the Properties View)

Name: PropertyChangeSupport

Instance Class Name: java.beans.PropertyChangeSupport

3. Right click on the addressbook-package you have created above and select

"New Child > EData Type"

4. Set the following properties (in the Properties View)

Name: PropertyChangeListener

Instance Class Name: java.beans.PropertyChangeListener

5. Right click on the addressbook-package you have created above and select

"New Child > EData Type"

6. Set the following properties (in the Properties View)

Name: PropertyChangeEvent

Instance Class Name: java.beans.PropertyChangeEvent



Now we are able to create our BaseObject:

1. Right click on the addressbook-package you have created above and select

"New Child > Eclass"

2. Set the following properties (in the Properties View)

Name: BaseObject

3. Right click the BaseObject and select "New Child > Eattribute"

4. Set the following properties (in the Properties View)

Name: id

Etype: EInt

5. Right click the BaseObject and select "New Child > Eattribute"

6. Set the following properties (in the Properties View)

Name: propertyChangeSupport

Etype: PropertyChangeSupport

Changeable: false

7. Right click the BaseObject and select "New Child > Eoperation"

8. Set the following properties (in the Properties View)

Name: addPropertyChangeListener

9. Right click the addPropertyChangeListener and select "New Child >

Eparameter"

10. Set the following properties (in the Properties View)

Name: listener

Etype: PropertyChangeListener

The final Ecore-Diagramm looks like this:



Create the Java- Code from the Ecore- model

So now it's time to get some create our domain model as Java-Objects. But instead of hand crafting the Java-Code let EMF create it for us:

1. Select the addressbook.ecore in the Project-Explorer

2. Right Click

3. Select New > Other ...

4. Select EMF Model



File:Emf-article-12 1.jpg

5. Click Next until you reach this window where you press "Load"



File:Emf-article-13 1.jpg

6. Click "Next" and afterwards "Finish"

We have no created a so called genmodel which is needed to create define/modify properties interesting when code is generated for us. We will make some minor changes like e.g. the name of the base package and suppressing of EMF Types in our public API.

1. Free public API from EMF Types

1. Select the 1st Addressbook in the Tree

2. Scroll in "Properties View" to the section "Model Feature Defaults"

3. Change "Suppress EMF Types" to true

2. Modify Base package name

1. Select the 2nd Addressbook in the Tree

2. Change the "base package" to "at.bestsolution.core.model"

Time for code generation:

1. Select the 1st Addressbook in the enmodel-Editor

2. Right Click

3. Select "Generate Model Code"



In the end your project looks like this:

Implementing at.bestsolution.addressbook.core.datasource



This document was converted from PDF using pdftohtml-0.36-145.7.i586.rpm, then to wiki markup using html2wiki. See also bug 195163.


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