private File getFile(URI uri) {

	if (uri != null) {

		/** to resolve this we need the workspace root */
		IWorkspaceRoot myWorkspaceRoot = ResourcesPlugin.getWorkspace()
				.getRoot();
		/** create an new IPath from the URI (decode blanks etc.) */
		IPath path = new Path(uri.toPlatformString(true));
		/** finally resolve the file with the workspace */
		IFile file = myWorkspaceRoot.getFile(path);

		if (file != null && file.getLocation() != null) {

			/** get java.io.File object */
			File f = file.getLocation().toFile();
			return f;
		}
	}
	return null;
}

public static void main(String[] args) throws IOException {
		Injector injector = new 
MyDslStandaloneSetup().createInjectorAndDoEMFRegistration();
		ResourceSet rs = injector.getInstance(ResourceSet.class);
		URI uri = URI.createURI("../org.xtext.example.mydsl/src/Test.mydsl");
		Resource r = rs.getResource(uri, true);
		Model m = (Model) r.getContents().get(0);
		String absolutePath = new 
File(m.eResource().getURI().toFileString()).getCanonicalPath();
		System.out.println(absolutePath);
	}