Keyboard Accessibility Through Command Framework

Keyboard shortcuts is usually much speedier than reaching out your mouse, moving it, pointing it to something and clicking. But there are some things which cannot be done that easily by keyboard shortcuts. For me, one of them is finding out a closed project and open it. Unfortunately, I've quite a large set of projects in my workspace and try to keep most them closed, when not used. In addition to that in the Package Explorer, I've the 'Closed Projects' filter on. So if I need to open a project, I've use the pull down menu, uncheck 'Closed Projects' navigate thru the working sets to find the right project and double click it. To enable keyboard access to this regular task, I decided to make use of Commands Framework.

The solution is to add a parameterized command, and in the values, I compute the projects which are closed. So when I press the awesome shortcut (Ctrl+3) it would display me the list of closed projects. With few keys, I can navigate to the project I want and open it. Lets see how to do it. First step is the command with the parameter:

<extension point="org.eclipse.ui.commands">
   <command
            defaultHandler="com.eclipse_tips.handlers.OpenProjectHandler"
            id="com.eclipse-tips.openProject.command"
            name="Open Project">
      <commandParameter
               id="com.eclipse-tips.openProject.projectNameParameter"
               name="Name"
               optional="false"
               values="com.eclipse_tips.handlers.ProjectNameParameterValues">
      </commandParameter>
   </command>
</extension>

And the handler:

public Object execute(ExecutionEvent event) throws ExecutionException {
 String projectName = event.getParameter("com.eclipse-tips.openProject.projectNameParameter");
 IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
 IProject project = root.getProject(projectName);
 try {
  project.open(null);
 } catch (CoreException e) {
  throw new ExecutionException("Error occured while open project", e);
 }
 return null;
}

For the parameter values, I look for closed projects and return them:

public Map<String, String> getParameterValues() {

 IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
 IProject[] projects = root.getProjects();
 Map<String, String> paramValues = new HashMap<String, String>();
 for (IProject project : projects) {
  if (project.exists() && !project.isOpen()) {
   paramValues.put(project.getName(), project.getName());
  }

 }
 return paramValues;
}

So finally, When I press Ctrl+3 and type OPN, I get the list:

This idea can be extended to provide keyboard accessibility to many functionalities. Say in an RCP mail application, you can add a command like 'Go To Mail' with parameter as the Subject/Sender:

Hmmm, if only the 'Built On Eclipse' mail app that I *have* to use, knows the existence of threads other than the UI thread :-(

From http://blog.eclipse-tips.com