Eclipse Cookbook

12.10. Coding a Plug-in Action

Problem

You have an action, and you need to make it actually do something.

Solution

Edit its .java file, and implement the support you need.

Discussion

Continuing the example developed over the previous three recipes, open Action1.java now if it’s not already open. This file contains plenty of TODOs, such as adding code to the action’s constructor to customize it, which we’ll ignore in this example. Here, we’ll display a message box when the user selects our menu item or clicks our toolbar button, as the plug-in developed earlier in this chapter did.

To do that, we’ll need an object that implements the Workbench window interface, IWorkbenchWindow. The object we need is passed to the init method in Action1.java, so we’ll begin by creating a private class variable, window, to hold it:

public class Action1 implements IWorkbenchWindowActionDelegate {
    private IWorkbenchWindow window;
        .
        .
        .

Then we’ll store the Workbench window passed to us in the init method in this variable like so:

public void init(IWorkbenchWindow window)  {
    this.window = window;
}

We can use this variable and the openInformation method of the MessageDialog class to display a message box with the message This plug-in is functional. in the action’s run method. To use the MessageDialog class, we first import it and then call it in the run method:

               import org.eclipse.jface.dialogs.MessageDialog;
        .
        .
        .
public void run(IAction action)  {
    MessageDialog.openInformation(
               window.getShell( ),
    "New Plug-in" ...