Hooking into Eclipse command execution

When I was working on implementing the Clips plug-in I wanted to intercept the Cut and Copy actions and automatically create clips from the selection. To my delight I discovered the necessary mechanism to exactly do that. Basically I had to add the following listener:

// Add listener to monitor Cut and Copy commands
ICommandService commandService = (ICommandService) PlatformUI
      .getWorkbench().getAdapter(ICommandService.class);
if (commandService != null) {
  commandService.addExecutionListener(new IExecutionListener() {

      public void notHandled(String commandId,
              NotHandledException exception) {
      }

      public void postExecuteFailure(String commandId,
              ExecutionException exception) {
      }

      public void postExecuteSuccess(String commandId,
              Object returnValue) {
          // Is it a Cut or Copy command
          if ("org.eclipse.ui.edit.copy".equals(commandId)
                  || "org.eclipse.ui.edit.cut".equals(commandId)) {
              Clipboard clipboard = new Clipboard(PlatformUI
                      .getWorkbench().getActiveWorkbenchWindow()
                      .getShell().getDisplay());
              Object contents = clipboard
                      .getContents(TextTransfer.getInstance());
              if (contents instanceof String) {
                  // Now do something with text selection
              }
          }

      }

      public void preExecute(String commandId, ExecutionEvent event) {
      }

  });
}

Cool huh?