Rich Client Tutorial Part 1
The Rich Client Platform (RCP) is an exciting new way to build Java applications that can compete with native applications on any platform. This tutorial is designed to get you started building RCP applications quickly. It has been updated for Eclipse 3.1.2
By Ed Burnette, SAS
July 28, 2004
Updated for 3.1.2: February 6, 2006
________________________________________
Introduction
Try this experiment: Show Eclipse to some friends or co-workers who haven't seen it before and ask them to guess what language it is written in. Chances are, they'll guess VB, C++, or C#, because those languages are used most often for high quality client side applications. Then watch the look on their faces when you tell them it was created in Java, especially if they are Java programmers.
Because of its unique open source license, you can use the technologies that went into Eclipse to create your own commercial quality programs. Before version 3.0, this was possible but difficult, especially when you wanted to heavily customize the menus, layouts, and other user interface elements. That was because the "IDE-ness" of Eclipse was hard-wired into it. Version 3.0 introduced the Rich Client Platform (RCP), which is basically a refactoring of the fundamental parts of Eclipse's UI, allowing it to be used for non-IDE applications. Version 3.1 updated RCP with new capabilities, and, most importantly, new tooling support to make it easier to create than before.
If you want to cut to the chase and look at the code for this part you can find it in the accompanying zip file. Otherwise, let's take a look at how to construct an RCP application.
Getting started
RCP applications are based on the familiar Eclipse plug-in architecture, (if it's not familiar to you, see the references section). Therefore, you'll need to create a plug-in to be your main program. Eclipse's Plug-in Development Environment (PDE) provides a number of wizards and editors that take some of the drudgery out of the process. PDE is included with the Eclipse SDK download so that is the package you should be using. Here are the steps you should follow to get started.
First, bring up Eclipse and select File > New > Project, then expand Plug-in Development and double-click Plug-in Project to bring up the Plug-in Project wizard. On the subsequent pages, enter a Project name such as org.eclipse.ui.tutorials.rcp.part1, indicate you want a Java project, select the version of Eclipse you're targeting (at least 3.1), and enable the option to Create an OSGi bundle manifest. Then click Next >.
Beginning in Eclipse 3.1 you will get best results by using the OSGi bundle manifest. In contrast to previous versions, this is now the default.
In the next page of the Wizard you can change the Plug-in ID and other parameters. Of particular importance is the question, "Would you like to create a rich client application?". Select Yes. The generated plug-in class is optional but for this example just leave all the other options at their default values. Click Next > to continue.
If you get a dialog asking if Eclipse can switch to the Plug-in Development Perspective click Remember my decision and select Yes (this is optional).
Starting with Eclipse 3.1, several templates have been provided to make creating an RCP application a breeze. We'll use the simplest one available and see how it works. Make sure the option to Create a plug-in using one of the templates is enabled, then select the Hello RCP template. This is RCP's equivalent of "Hello, world". Click Finish to accept all the defaults and generate the project (see Figure 1). Eclipse will open the Plug-in Manifest Editor. The Plug-in Manifest editor puts a friendly face on the various configuration files that control your RCP application.
Figure 1. The Hello World RCP project was created by a PDE wizard.
Taking it for a spin
Trying out RCP applications used to be somewhat tedious. You had to create a custom launch configuration, enter the right application name, and tweak the plug-ins that were included. Thankfully the PDE keeps track of all this now. All you have to do is click on the Launch an Eclipse Application button in the Plug-in Manifest editor's Overview page. You should see a bare-bones Workbench start up (see Figure 2).
Figure 2. By using the templates you can be up and running an RCP application in minutes.
Making it a product
In Eclipse terms a product is everything that goes with your application, including all the other plug-ins it depends on, a command to run the application (called the native launcher), and any branding (icons, etc.) that make your application distinctive. Although as we've just seen you can run a RCP application without defining a product, having one makes it a whole lot easier to run the application outside of Eclipse. This is one of the major innovations that Eclipse 3.1 brought to RCP development.
Some of the more complicated RCP templates already come with a product defined, but the Hello RCP template does not so we'll have to make one.
In order to create a product, the easiest way is to add a product configuration file to the project. Right click on the plug-in project and select New > Product Configuration. Then enter a file name for this new configuration file, such as part1.product. Leave the other options at their default values. Then click Finish. The Product Configuration editor will open. This editor lets you control exactly what makes up your product including all its plug-ins and branding elements.
In the Overview page, select the New... button to create a new product extension. Type in or browse to the defining plug-in (org.eclipse.ui.tutorials.rcp.part1). Enter a Product ID such as product, and for the Product Application select org.eclipse.ui.tutorials.rcp.part1.application. Click Finish to define the product. Back in the Overview page, type in a new Product Name, for example RCP Tutorial 1.
In Eclipse 3.1.0 if you create the product before filling in the Product Name you may see an error appear in the Problems view. The error will go away when you Synchronize (see below). This is a known bug that is fixed in newer versions. Always use the latest available maintenance release for the version of Eclipse you're targeting!
Now select the Configuration tab and click Add.... Select the plug-in you just created (org.eclipse.ui.tutorials.rcp.part1) and then click on Add Required Plug-ins. Then go back to the Overview page and press Ctrl+S or File > Save to save your work.
If your application needs to reference plug-ins that cannot be determined until run time (for example the tomcat plug-in), then add them manually in the Configuration tab.
At this point you should test out the product to make sure it runs correctly. In the Testing section of the Overview page, click on Synchronize then click on Launch the product. If all goes well, the application should start up just like before.
Plug-ins vs. features
On the Overview page you may have noticed an option that says the product configuration is based on either plug-ins or features. The simplest kind of configuration is one based on plug-ins, so that's what this tutorial uses. If your product needs automatic update or Java Web Start support, then eventually you should convert it to use features. But take my advice and get it working without them first.
Running it outside of Eclipse
The whole point of all this is to be able to deploy and run stand-alone applications without the user having to know anything about the Java and Eclipse code being used under the covers. For a real application you may want to provide a self-contained executable generated by an install program like InstallShield or NSIS. That's really beyond the scope of this article though, so we'll do something simpler.
The Eclipse plug-in loader expects things to be in a certain layout so we'll need to create a simplified version of the Eclipse install directory. This directory has to contain the native launcher program, config files, and all the plug-ins required by the product. Thankfully, we've given the PDE enough information that it can put all this together for us now.
In the Exporting section of the Product Configuration editor, click the link to Use the Eclipse Product export wizard. Set the root directory to something like RcpTutorial1. Then select the option to deploy into a Directory, and enter a directory path to a temporary (scratch) area such as C:\Deploy. Check the option to Include source code if you're building an open source project. Press Finish to build and export the program.
The compiler options for source and class compatibility in the Eclipse Product export wizard will override any options you have specified on your project or global preferences. As part of the Export process, the plug-in is code is recompiled by an Ant script using these options.
The application is now ready to run outside Eclipse. When you're done you should have a structure that looks like this in your deployment directory:
RcpTutorial1
| .eclipseproduct
| eclipse.exe
| startup.jar
+--- configuration
| config.ini
+--- plugins
org.eclipse.core.commands_3.1.0.jar
org.eclipse.core.expressions_3.1.0.jar
org.eclipse.core.runtime_3.1.2.jar
org.eclipse.help_3.1.0.jar
org.eclipse.jface_3.1.1.jar
org.eclipse.osgi_3.1.2.jar
org.eclipse.swt.win32.win32.x86_3.1.2.jar
org.eclipse.swt_3.1.0.jar
org.eclipse.ui.tutorials.rcp.part1_1.0.0.jar
org.eclipse.ui.workbench_3.1.2.jar
org.eclipse.ui_3.1.2.jar
Note that all the plug-ins are deployed as jar files. This is the recommended format starting in Eclipse 3.1. Among other things this saves disk space in the deployed application.
Previous versions of this tutorial recommended using a batch file or shell script to invoke your RCP program. It turns out this is a bad idea because you will not be able to fully brand your application later on. For example, you won't be able to add a splash screen. Besides, the export wizard does not support the batch file approach so just stick with the native launcher.
Give it a try! Execute the native launcher (eclipse or eclipse.exe by default) outside Eclipse and watch the application come up. The name of the launcher is controlled by branding options in the product configuration.
Troubleshooting
Error: Launching failed because the org.eclipse.osgi plug-in is not included...
You can get this error when testing the product if you've forgotten to list the plug-ins that make up the product. In the Product Configuration editor, select the Configuration tab, and add all your plug-ins plus all the ones they require as instructed above.
Compatibility and migration
If you are migrating a plug-in from version 2.1 to version 3.1 there are number of issues covered in the on-line documentation that you need to be aware of. If you're making the smaller step from 3.0 to 3.1, the number of differences is much smaller. See the References section for more information.
One word of advice: be careful not to duplicate any information in both plug-in.xml and MANIFEST.MF. Typically this would not occur unless you are converting an older plug-in that did not use MANIFEST.MF into one that does, and even then only if you are editing the files by hand instead of going through the PDE.
Conclusion
In part 1 of this tutorial, we looked at what is necessary to create a bare-bones Rich Client application. The next part will delve into the classes created by the wizards such as the WorkbenchAdvisor class. All the sample code for this part may be found in the accompanying zip file.
References
RCP Tutorial Part 2
RCP Tutorial Part 3
Eclipse Rich Client Platform
RCP Browser example (project org.eclipse.ui.examples.rcp.browser)
PDE Does Plug-ins
How to Internationalize your Eclipse Plug-in
Notes on the Eclipse Plug-in Architecture
Plug-in Migration Guide: Migrating to 3.1 from 3.0
Plug-in Migration Guide: Migrating to 3.0 from 2.1
To discuss or report problems in this article see bug 104146.
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Java and all Java-based trademarks and logos are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States, other countries, or both.
Microsoft and Windows are trademarks of Microsoft Corporation in the United States, other countries, or both.
Other company, product, and service names may be trademarks or service marks of others.
Rich Client Tutorial Part 2
The Rich Client Platform (RCP) allows you to build Java applications that can compete with native applications on any platform. Part 1 of the tutorial introduced you to the platform and the steps used to build the smallest possible RCP program. In part 2 we'll look at what we did in more detail and introduce some of the configuration classes that let you take control of much of the layout and functionality of an RCP application. This part has been updated for Eclipse 3.1.2
By Ed Burnette, SAS
August 9, 2004
Updated for 3.1.2: February 6, 2006
________________________________________
Introduction
In early versions of Eclipse, many functions of the IDE were hard-wired into the code. These included the name and location of the File menu, the title of the Workbench Window, and the existence of the status bar. This was fine for the IDE but when people started to use Eclipse as a basis for non-IDE programs, sometimes these things didn't make sense. Although all the source code was provided, it was inconvenient to find the right places that had to be changed.
So, beginning in Eclipse 3.0, the designers refactored the API to make these and other hard-wired aspects of the user interface controllable through public API. Subsequent releases have fine tuned that API and provided tooling in the Plug-in Development Environment (PDE) to lower the barriers to getting started using it. However, you'll eventually need to look behind the PDE wizards and editors to really understand what is going on.
In this part we'll examine the code and configuration files created in Part 1 of the tutorial. To keep the parts separate I've recreated the examples for each part under a different name. All the sample code for Part 2 may be found in the part2.zip archive file.
If you're following along with this tutorial in Eclipse and you're thinking of just renaming your old project, I don't recommend it. In Eclipse 3.1, Refactor > Rename does not work well on plug-in projects due to all the internal references in XML files and strings that don't participate. Hopefully this will be fixed in a future release.
Before we go any further let's clear up some possible confusion about the relationship between Applications, Workbenches, and Workbench Windows.
Applications, Workbenches, and Workbench Windows
The Application is a class you create that acts as your RCP program's main routine. You can think of it as the controller for the program. Just like the controller in a Model2 architecture, it is short and sweet and doesn't change significantly for different projects. All it does is create a Workbench and attach another class called a Workbench Advisor to it (Workbench Advisors will be covered more later).
The Workbench is declared and maintained for you as part of the RCP framework. There is only one Workbench but it can have more than one visible top-level Workbench Window. For example, in the Eclipse IDE, when you first start Eclipse you will see one Workbench Window, but if you select Window > New Window a second window pops up -- two Workbench Windows, but only one Workbench.
Ok, now that that's out of the way, let's see what those PDE wizards did for us, starting with the plug-in manifest.
Plug-in manifest
The plug-in manifest ties all the code and resources together. When you first create a plug-in, Eclipse will create and open the manifest for you automatically. The manifest is split into two files: MANIFEST.MF and plugin.xml. PDE provides a fancy editor to modify the options stored in these files (see Figure 1) but also allows you to edit the source directly.
Figure 1. The plug-in manifest editor provides a single interface for editing the manifest and related files. The tabs along the bottom of the editor access all the different sections in the GUI or the raw text files.
MANIFEST.MF
The OSGi bundle manifest is stored in MANIFEST.MF. OSGi is the name of a standard that Eclipse uses for dynamically loading plug-ins (see refererences). Listing 1 shows the OSGi bundle manifest generated by the plug-in wizard. Everything in this file can be edited by the Manifest editor, so there should be no need to edit it by hand. However if you need to, just double-click it in the Package Explorer to bring up the Manifest editor, then click on the MANIFEST.MF tab in the editor to see and modify the source.
For backwards compatability with Eclipse 2.1, Eclipse will recognize and load plug-ins that do not use MANIFEST.MF. However, this incurs a small performance penalty and is not recommended for plug-ins targeting Eclipse 3.0 and later.
Listing 1. MANIFEST.MF
Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: Part2 Plug-in
Bundle-SymbolicName: org.eclipse.ui.tutorials.rcp.part2; singleton:=true
Bundle-Version: 1.0.0
Bundle-Activator: org.eclipse.ui.tutorials.rcp.part2.Part2Plugin
Bundle-Localization: plugin
Require-Bundle: org.eclipse.ui,
org.eclipse.core.runtime
Eclipse-AutoStart: true
plugin.xml
The Eclipse extension manifest is called plugin.xml. It's used for defining and using Eclipse extension points, so if you're not using extension points then this file may be omitted. Extension points are the fundamental way that Eclipse plug-ins are tied together so if you're not familiar with them see one of the articles in the Reference section. Listing 2 shows the plugin.xml file created by the PDE wizard.
Listing 2. plugin.xml
<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.0"?>
<plugin>
<extension
id="application"
point="org.eclipse.core.runtime.applications">
<application>
<run
class="org.eclipse.ui.tutorials.rcp.part2.Application">
</run>
</application>
</extension>
<extension
point="org.eclipse.ui.perspectives">
<perspective
name="Part2 Perspective"
class="org.eclipse.ui.tutorials.rcp.part2.Perspective"
id="org.eclipse.ui.tutorials.rcp.part2.perspective">
</perspective>
</extension>
<extension
id="product"
point="org.eclipse.core.runtime.products">
<product
application="org.eclipse.ui.tutorials.rcp.part2.application"
name="RCP Tutorial 2"/>
</extension>
</plugin>
The class name of the main program is defined with the org.eclipse.core.runtime.applications extension.
Although it's not an absolute requirement, I recommend keeping your id's and your class names the same except possibly for case. For historical reasons, Eclipse prepends the plug-in's id to the id of your top level plug-in elements (like extension). For example, even though the plugin.xml in listing 2 says id="application", the fully qualified id for that extension is org.eclipse.ui.tutorials.rcp.part2.application. Since the perspective's id is written on a sub-element (perspective) it has to be spelled out completely in the manifest (org.eclipse.ui.tutorials.rcp.part2.perspective). By convention only, package names and ids are lower case and class names are Pascal Case.
The main program
The org.eclipse.core.runtime.applications extension tells the Eclipse runtime the name of your main program. This is a class that implements IPlatformRunnable and a run() method. Listing 3 shows the simple implementation supplied by the plug-in wizard.
Listing 3. Application.java
package org.eclipse.ui.tutorials.rcp.part2;
import org.eclipse.core.runtime.IPlatformRunnable;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.PlatformUI;
/**
* This class controls all aspects of the application's execution
*/
public class Application implements IPlatformRunnable {
/* (non-Javadoc)
* @see org.eclipse.core.runtime.IPlatformRunnable#run(java.lang.Object)
*/
public Object run(Object args) throws Exception {
Display display = PlatformUI.createDisplay();
try {
int returnCode = PlatformUI.createAndRunWorkbench(display, new ApplicationWorkbenchAdvisor());
if (returnCode == PlatformUI.RETURN_RESTART) {
return IPlatformRunnable.EXIT_RESTART;
}
return IPlatformRunnable.EXIT_OK;
} finally {
display.dispose();
}
}
}
The default perspective
A Perspective is a set of visible views, editors, and menus including their positions and sizes. In an RCP program you must define at least one perspective and make it the default. Perspectives are created by implementing IPerspectiveFactory using the class name referred to by the org.eclipse.ui.perspectives extension. See Listing 4 for the implementation provided by the plug-in wizard. The important part of this interface is the createInitialLayout() method where you position and open any views and/or editors you'd like the user to start with. So far in this example we haven't created any views so it's a pretty boring perspective.
Listing 4. Perspective.java
package org.eclipse.ui.tutorials.rcp.part2;
import org.eclipse.ui.IPageLayout;
import org.eclipse.ui.IPerspectiveFactory;
public class Perspective implements IPerspectiveFactory {
public void createInitialLayout(IPageLayout layout) {
}
}
The Advisor classes
The main program referenced a class called ApplicationWorkbenchAdvisor. This is one of three Advisor classes that you use to configure all aspects of the Workbench such as the title, menu bars, and so on. These are the most important classes for an RCP developer to understand. You extend the base version of the class, for example WorkbenchAdvisor, in your RCP application and override one or more of the methods to set whatever options you want. Let's examine these classes now in more detail.
Workbench Advisor
Methods in this class are called from the platform to notify you at every point in the lifecycle of the Workbench. They also provide a way to handle exceptions in the event loop, and provide important parameters to the Workbench such as the default perspective. With the exception of createWorkbenchWindowAdvisor() and getInitialWindowPerspectiveId(), the methods on WorkbenchAdvisor do not have to be overridden. Listing 5 shows the implementation that was provided by the plug-in wizard.
Listing 5. ApplicationWorkbenchAdvisor.java
package org.eclipse.ui.tutorials.rcp.part2;
import org.eclipse.ui.application.IWorkbenchWindowConfigurer;
import org.eclipse.ui.application.WorkbenchAdvisor;
import org.eclipse.ui.application.WorkbenchWindowAdvisor;
public class ApplicationWorkbenchAdvisor extends WorkbenchAdvisor {
private static final String PERSPECTIVE_ID = "org.eclipse.ui.tutorials.rcp.part2.perspective";
public WorkbenchWindowAdvisor createWorkbenchWindowAdvisor(IWorkbenchWindowConfigurer configurer) {
return new ApplicationWorkbenchWindowAdvisor(configurer);
}
public String getInitialWindowPerspectiveId() {
return PERSPECTIVE_ID;
}
}
Why not an interface? You'll notice that WorkbenchAdvisor is an abstract class. For the most part, Eclipse APIs shun abstract classes in favor of interfaces and base classes that implement those interfaces. In this case, the designers intend for WorkbenchAdvisor to always be implemented by the RCP application, and the base class doesn't contain any significant functionality. Also it is very likely that new methods will need to be added to the base class in the future (something that is difficult using interfaces). So this was a deliberate design choice. See the article on evolving Java APIs in the reference section for more tips.
Workbench lifecycle hooks
The Workbench Advisor class has several methods that are called at defined points in the Workbench's lifecycle (see Table 1). By overriding these you can run whatever code you want at these points.
Table 1. Workbench lifecycle hooks provided by WorkbenchAdvisor.
Method Description Parameter(s)
initialize Called first to perform any setup such as parsing the command line, registering adapters, declaring images, etc.. IWorkbenchConfigurer
preStartup Called after initialization but before the first window is opened. May be used to set options affecting which editors and views are initially opened.
postStartup Called after all windows have been opened or restored, but before the event loop starts. It can be used to start automatic processes and to open tips or other windows.
preShutdown Called after the event loop has terminated but before any windows have been closed.
postShutdown Called after all windows are closed during Workbench shutdown. This can be used to save the current application state and clean up anything created by initialize.
Event loop hooks
The event loop is the code that is running most of the time during the life of the Workbench. It handles all user inputs and dispatches them to the right listeners. RCP provides a couple of hooks to handle crashes and perform work during idle time (see Table 2). Note however that the Jobs interface (see References) is a better way of performing long running work than this idle hook.
Table 2. Event loop hooks provided by WorkbenchAdvisor.
Method Description Parameter(s)
eventLoopException Called if there is an unhandled exception in the event loop. The default implementation will log the error. Throwable
eventLoopIdle Called when the event loop has nothing to do. Display
Information getting hooks
Next, there are few methods you can implement that the platform will call to get information about your application (see Table 3). The most important one (and the only one that is not optional) is getInitialWindowPerspectiveId. We used this in Listing 5 to return the id of the starting perspective.
Table 3. Information request methods you can override in WorkbenchAdvisor.
Method Description Parameter(s)
getDefaultPageInput Return the default input for new workbench pages. Defaults to null.
getInitialWindowPerspectiveId Return the initial perspective used for new workbench windows. This is a required function that has no default.
getMainPreferencePageId Return the preference page that should be displayed first. Defaults to null, meaning the pages should be arranged alphabetically.
Advanced configuration
The WorkbenchAdvisor events above should be sufficient for most applications, but just in case, RCP provides another method to take complete control of how your application windows and controls are created. It's listed in Table 4 for completeness but I don't expect many programs will need it.
Table 4. Advanced methods in org.eclipse.ui.application.WorkbenchAdvisor.
Method Description Parameter(s)
openWindows Open all Workbench windows on startup. The default implementation tries to restore the previously saved workbench state.
Workbench Window Advisor
This class is used to control the status line, toolbar, title, window size, and other things you'll almost certainly want to customize. You can also use it to hook into all the various lifecycle events of the Workbench Windows. Listing 6 shows the implementation provided by the plug-in wizard.
Listing 6. ApplicationWorkbenchWindowAdvisor.java
package org.eclipse.ui.tutorials.rcp.part2;
import org.eclipse.swt.graphics.Point;
import org.eclipse.ui.application.ActionBarAdvisor;
import org.eclipse.ui.application.IActionBarConfigurer;
import org.eclipse.ui.application.IWorkbenchWindowConfigurer;
import org.eclipse.ui.application.WorkbenchWindowAdvisor;
public class ApplicationWorkbenchWindowAdvisor extends WorkbenchWindowAdvisor {
public ApplicationWorkbenchWindowAdvisor(IWorkbenchWindowConfigurer configurer) {
super(configurer);
}
public ActionBarAdvisor createActionBarAdvisor(IActionBarConfigurer configurer) {
return new ApplicationActionBarAdvisor(configurer);
}
public void preWindowOpen() {
IWorkbenchWindowConfigurer configurer = getWindowConfigurer();
configurer.setInitialSize(new Point(400, 300));
configurer.setShowCoolBar(false);
configurer.setShowStatusLine(false);
configurer.setTitle("Hello RCP");
}
}
Methods on WorkbenchWindowAdvisor (see Table 5 and Table 6) will all need access to a Configurer interface (in this case, IWorkbenchWindowConfigurer) in order to do anything so they're expected to call getWindowConfigurer() to fetch it. You call methods on the Configurer interfaces to actually change the options. These interfaces are not covered in any detail in this tutorial but you can refer to their Javadoc for more information.
Table 5. Workbench window lifecycle hooks provided by WorkbenchWindowAdvisor.
Method Description Parameter(s)
preWindowOpen Called in the constructor of the Workbench Window. Use this method to set options such as whether or not the window will have a menu bar. However none of the window's widgets have been created yet so they can't be referenced in this method.
postWindowRestore Optionally called for cases when a window has been restored from saved state but before it is opened.
postWindowCreate Called after a window has been restored from saved state or created from scratch but before it is opened.
openIntro Called immediately before a window is opened in order to create the Intro component (if any).
postWindowOpen Called right after the Workbench window is opened. Can be used to tweak any of the window's widgets, for example to set a title or change its size.
preWindowShellClose Called before the Workbench window is closed (technically, before its shell is closed). This is the only function that can veto the close, so it's a good place for an "Are you sure" kind of dialog.
postWindowClose Called after the Workbench window is closed. Can be used to clean up anything created by preWindowOpen.
Table 6. Advanced methods in WorkbenchWindowAdvisor.
Method Description Parameter(s)
createWindowContents Creates the contents of one window. Override this method to define custom contents and layout. Shell
createEmptyWindowContents Like createWindowContents, but used when the window has no open pages. Override this method to show something other than the default window background. Composite
ActionBar Advisor
In Eclipse jargon, "action bar" is a catch-all term for menus, toolbars, and status bars. The ActionBar Advisor handles creating Actions within these locations. A plug-in can also contribute actions dynamically with its plugin.xml file. See Listing 7 for the implementation provided by the plug-in wizard and Table 7 for the methods.
The whole action, command and keybinding system is a bit of a mess in Eclipse 3.1. For example you can't add combo boxes to action bars, and plugin.xml can't contribute actions to the status bar. Getting key bindings to work involves multiple steps. Hopefully this will be cleaned up in a future release.
Listing 7. ApplicationActionBarAdvisor.java
package org.eclipse.ui.tutorials.rcp.part2;
import org.eclipse.jface.action.IMenuManager;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.application.ActionBarAdvisor;
import org.eclipse.ui.application.IActionBarConfigurer;
public class ApplicationActionBarAdvisor extends ActionBarAdvisor {
public ApplicationActionBarAdvisor(IActionBarConfigurer configurer) {
super(configurer);
}
protected void makeActions(IWorkbenchWindow window) {
}
protected void fillMenuBar(IMenuManager menuBar) {
}
}
Table 7. Methods you can override in ActionBarAdvisor.
Method Description Parameter(s)
makeActions Called to create the actions used in the fill methods. IWorkbenchWindow
fillMenuBar Called to fill the menu bar with the main menus for the window. IMenuManager
fillCoolBar Called to fill the cool bar with the main toolbars for the window. ICoolBarManager
fillStatusLine Called to fill the status line with the main status line contributions for the window. IStatusLineManager
isApplicationMenu Return true if the menu is one of yours. OLE specific; see Javadoc for details. String
Plug-in class
The plug-in class is an optional singleton class that can be used to store global information for the plug-in. It's also a convenient place to put a few static utility functions used by other classes in the plug-in. See Listing 8 for the plug-in class that was created for us by the plug-in wizard.
Listing 8. Part2Plugin.java
package org.eclipse.ui.tutorials.rcp.part2;
import org.eclipse.ui.plugin.*;
import org.eclipse.jface.resource.ImageDescriptor;
import org.osgi.framework.BundleContext;
/**
* The main plugin class to be used in the desktop.
*/
public class Part2Plugin extends AbstractUIPlugin {
//The shared instance.
private static Part2Plugin plugin;
/**
* The constructor.
*/
public Part2Plugin() {
plugin = this;
}
/**
* This method is called upon plug-in activation
*/
public void start(BundleContext context) throws Exception {
super.start(context);
}
/**
* This method is called when the plug-in is stopped
*/
public void stop(BundleContext context) throws Exception {
super.stop(context);
plugin = null;
}
/**
* Returns the shared instance.
*/
public static Part2Plugin getDefault() {
return plugin;
}
/**
* Returns an image descriptor for the image file at the given
* plug-in relative path.
*
* @param path the path
* @return the image descriptor
*/
public static ImageDescriptor getImageDescriptor(String path) {
return AbstractUIPlugin.imageDescriptorFromPlugin("org.eclipse.ui.tutorials.rcp.part2", path);
}
}
Build properties
The build.properties file (see Listing 9) will be needed when exporting the application for others to use. In particular if your application needs any resources like icons they should be listed here in the bin.includes section. The Plug-in Manifest editor provides a convenient interface to modify this file that is less error-prone than modifying it by hand.
Listing 9. build.properties
source.. = src/
output.. = bin/
bin.includes = plugin.xml,\
META-INF/,\
.
Conclusion
In part 2 of this tutorial, we looked at some of the API of the Rich Client Platform that allows you to develop customized native-looking client-side Java programs. The next part will delve into branding and deploying your application so others can use it. All the sample code for this part is included in the part2.zip archive file that accompanies this document.
References
RCP Tutorial Part 1
RCP Tutorial Part 3
Eclipse Rich Client Platform
The Equinox project (OSGi in Eclipse)
How to Internationalize your Eclipse Plug-in
PDE Does Plug-ins
Notes on the Eclipse Plug-in Architecture
On the Job: The Eclipse Jobs API
Almost All Java Web Apps Need Model 2 (introduction to the Model 2 architecture)
Evolving Java-based APIs
To discuss or report problems in this article see bug 104170.
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