etc.to

Getting the IWorkbench

To get the IWorkbench from a plugin use IWorkbench wb = PlatformUI.getWorkbench();

Getting the IWorkspace

The workspace can be gotten using ResourcesPlugin.getWorkspace();

Getting the "root" IResource of the workspace

This can be gotten from IWorkspace.getRoot()

Getting the "active" editor from an Action/command

public ITextEditor getTextEditor()
{
IWorkbench wb = PlatformUI.getWorkbench();
IWorkbenchWindow win = wb.getActiveWorkbenchWindow();
IWorkbenchPage page = win.getActivePage();
IEditorPart editor = page.getActiveEditor();
return (ITextEditor) editor;
}