Recipe 12.6 Writing a Plug-in from a Skeleton

12.6.1 Problem

You want to develop the code for a plug-in yourself, from scratch.

12.6.2 Solution

You can create a skeletal plug-in project in the Plug-in Code Generators pane by selecting Default Plug-In Structure. We'll do that here and develop the rest of the plug-in from that starting point.

12.6.3 Discussion

As an example, we'll create the plug-in created earlier in this chapter that displayed menus, but this time, we'll do the work ourselves instead of relying entirely on a wizard. We will use a wizard to get started, however, so select File New Project. In the New Project dialog, select Plug-in Development in the left box and Plug-in Project in the right box, and click Next. In the next pane, enter the new project's name, org.cookbook.ch12.MenuPlugInFromScratch, and click Next to open the Plug-in Project Structure pane. Click Next again to accept the defaults.

In the Plug-in Code Generators pane, select Default Plug-In Structure, as shown in Figure 12-13, and click Next.

Figure 12-13. Selecting a plug-in wizard

The next dialog enables you to set the provider name, which we'll set to Eclipse Cookbook. Because we'll be writing our own code here, uncheck the items in the "Plug-in code generation options" box, as shown in Figure 12-14, and click Finish.

Figure 12-14. Setting the provider name

Clicking Finish creates the MenuPlugInFromSratch plug-in, opening its manifest in Eclipse. Click the Source tab, which displays the XML in plugin.xml. That XML should look like this:

<?xml version="1.0" encoding="UTF-8"?>
<plugin
   id="org.cookbook.ch12.MenuPlugInFromScratch"
   name="MenuPlugInFromScratch Plug-in"
   version="1.0.0"
   provider-name="Eclipse Cookbook"
   class="org.cookbook.ch12.MenuPlugInFromScratch.MenuPlugInFromScratchPlugin">

   <runtime>
      <library name="MenuPlugInFromScratch.jar"/>
   </runtime>
   <requires>
      <import plugin="org.eclipse.core.resources"/>
      <import plugin="org.eclipse.ui"/>
   </requires>

</plugin>

That's our new plug-in's manifest. Our goal in this plug-in is to add a new menu item and a button in the toolbar. To make things happen in a plug-in, you define actions and action sets. See the following recipe for further details.

12.6.4 See Also

Recipe 12.2 on creating plugin.xml; Recipe 12.9 on creating an action set; Recipe 12.10 on coding an Eclipse action; Chapter 11 and Chapter 12 in Eclipse (O'Reilly).