Overview

1.1. Introduction

Eclipse RAP is a Eclipse based platform for Ajax web applications which provides part of the API of Eclipse RCP . Eclipse RAP allows to use Eclipse RCP paradigm for developing Ajax web-applications.

RAP is based on the OSGI Implemantion equibox. It is possible to run Eclipse RAP applications via the OSGi servlet bridge in a servlet container, e.g. Jetty.

Eclipse RAP supports extension points, views, perspectives, selection service, commands, handlers, editors and databinding.

Eclipse archives this by providing its own implementations for SWT, JFace and the Workbench. Eclipse RAP replaces SWT with RWT (RAP widget toolkit) layer. This toolkit is based on the qooxdoo Ajax library. RWT is a distributed system; every RWT widget has a client and a server part. These part communicate via Ajax.

During development Eclipse RAP applications run in the embedded webserver Jetty.

1.2. Differences to Eclipse RCP

Eclipse RAP does not provide all the possibilities Eclipse RCP (or the underlying plugins provide. For example Eclipse RAP has no Graphics Context which can be used in SWT to draw directly onto the SWT widgets.

Each Eclipse RAP releases provides more functionality so that the differences between Eclipse RCP and Eclipse RAP are getting smaller every day.

Eclipse RAP installation

2.1. Workspace

Before continuing create a new workspace for your Eclipse RAP projects. As you have to change the target platform to compile against Eclipse RAP your other project will not continue to work.

2.2. Install Eclipse RAP

Use the Eclipse Update Manager to install the Rich Ajax Platform. This package can be found under the Galileo Update site under "Web, XML, and Java EE Development" -> Rich Ajax Platform SDK (RAP) .

2.3. Install Target Platform

Eclipse RAP have its own target platform. A target platform contains the artifacts, e.g. plugins, against which the Eclipse plugins are compiled. For example Eclipse RAP does not rely on SWT but on RWT therefore the target platform must provide these.

Download the RAP target platform from Eclipse RAP downloads and unzip it into a new directory, e.g. "c:\EclipseRAPTarget".

Change the target platform under Window -> Preferences -> Plug-in Development -> Target Platform

Press "Add".

Select "Nothing" as template and maintain the directory of the target platform as the location.

Switch to your new Target Platform.

Your first Eclipse RAP application

3.1. Create Project

Create a new plugin project "sawan.modi.rap.first" via File -> New -> Project -> Plug-in Development -> Plug-in Project. Perform the following selection.

Select the "RAP Hello World" template and press "Finish".

3.2. Run

Select your "MANIFEST.MF", right click on it, select Run-as-> Rap Application.

This should start your first RAP application.

Congratulations! You have your first Eclipse RAP application running.

3.3. Entrypoint

Eclipse RAP requires an entrypoint similar to "org.eclipse.core.runtime.applications" for Eclipse RCP applications. The entrypoint for Eclipse RAP is defined via "org.eclipse.rap.ui.workbench.entrypoint".

View your Entrypoint via the entension "org.eclipse.rap.ui.workbench.entrypoint" in the file "MANIFEST.MF" . Please note that the parameter "default" is used in your runtime configuration of RAP.

.

3.4. Extending your UI

Create now a view. Select therefore in MANIFEST.MF the tab extension and add the extension point "org.eclipse.ui.views". Add then add the view with the id "sawan.modi.rap.first.View". The procedure is the same as for Eclipse RCP application which is described in Eclipse RCP Application.

Create the following view class.

    
package sawan.modi.rap.first;

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Text;
import org.eclipse.ui.part.ViewPart;

public class View extends ViewPart {

 public static final String ID = "sawan.modi.rap.first.View";

 @Override
 public void createPartControl(Composite parent) {
  Label label = new Label(parent, SWT.NONE);
  label.setText("This is my label");
  Text text = new Text(parent, SWT.NONE);
  text.setText("Input");
 }

 @Override
 public void setFocus() {

 }

}

   

Add the view to the perspective by changing Perspective.java to the following.

    
package sawan.modi.rap.first;

import org.eclipse.ui.IPageLayout;
import org.eclipse.ui.IPerspectiveFactory;

/**
* Configures the perspective layout. This class is contributed
* through the plugin.xml.
*/
public class Perspective implements IPerspectiveFactory {

 public void createInitialLayout(IPageLayout layout) {
  String editorArea = layout.getEditorArea();
  layout.setEditorAreaVisible(false);
  
  layout.addStandaloneView(View.ID,  false, IPageLayout.LEFT, 0.25f, editorArea);
 
 }
}

   

Run your application and see your new view in actions.

Eclipse RAP supports most of the API JFace and Eclipse RCP support. If you want to learn how you can extend your Eclipse RAP application you can review Eclipse RCP App.

Of course Eclipse RAP does only support a subset of these API (but this is increasing every release) so the best way of exploring it is to build your application and see which API are available.

Theming

4.1. Overview

A Eclipse RAP application look similar to a Eclipse RCP application running in a browser. While this is cool, it is not necessary always what you want if you develop a web application.

Eclipse RAP therefore provides the possibility to change the look of the application via theming. Themes can be defined in css like files. The following will give an demonstration how to do this.

4.2. Example

Create a new Eclipse RAP project "sawan.modi.rap.theming". Use the "RAP Mail Template" as template.

Create a new folder "themes" in your project.

Add the directory themes to your build.properties. Otherwise the files from themes will not get included in an exported product.

Add the extension point "org.eclipse.rap.ui.themes". Use the following settings.

Create now the following file "theme.css" in the folder themes.

    

* {

   backgound-color: yellow;

   color: red;

 }




   

Add now the "org.eclipse.rap.ui.branding" extension point which the following settings. Important is the servletName "rap" as this is used in your runtime configuration, your entrypoint and the theme you want to use.

This will result in the following rap application display.

Single Sourcing

With Eclipse RAP it is possible to develop a desktop application Eclipse RCP and a web application with the same source code. This is called single sourcing.

To use the same code basis for Eclipse RCP and Eclipse RAP you can use OSGi fragments. Fragments are special OSGi bundles, which extend another bundle and are merged at runtime with the extended bundle. You can put the RCP or RAP specific functionality into a fragment. If you create a RAP application you use the RAP fragment or if you want to create a RCP application you use the RCP fragment.

One difference between RCP and RAP is that in RCP you only have one user. In case you are using singletons which should be user specific then you have to use the RAP class SessionSingleBase. In case you have a real singleton for several users you need to consider concurrency issues. JFace Preference are already correctly supported in RAP.

Thank you

Thank you for practicing with this tutorial.

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