How to indicate a file has changed after modifying it using IFile - eclipse

Question

I've been able to successfully update the contents of a file via a popup menu extension I've created underneath the Source menu that comes up when right-clicking on a file.
I'd like to indicate that the file has been changed and needs to be saved. Right now, the file contents change and save automatically. I thought the IFile.touch method would cause the file to be in a state where it needed to be saved but I'm not seeing that happen.
Here's my code...
public Object execute(ExecutionEvent event) throws ExecutionException {
IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindowChecked(event);
IEditorPart editorPart = HandlerUtil.getActiveEditor(event);
IEditorInput input = editorPart.getEditorInput();
InputStream is = null;
if (input instanceof FileEditorInput) {
IFile file = ((FileEditorInput) input).getFile();
try {
is = file.getContents();
String originalContents = convertStreamToString(is);
String newContents = originalContents + "testing changing the contents...";
InputStream newInput = new ByteArrayInputStream(newContents.getBytes());
file.setContents(newInput, false, true, null);
file.touch(null);
} catch (CoreException e) {
MessageDialog.openError(
window.getShell(),
"Generate Builder Error",
"An Exception has been thrown when interacting with file " + file.getName() +
": " + e.getMessage());
}
}
return null;
}

Answer 1

If you want the file's contents marked as needing to be saved, you need to be interacting with the in-memory representation you want to prompt as needing to be saved--the editor from which you're getting the input.

Answer 2

Based on help from nitind and this post - Replace selected code from eclipse editor thru plugin comand - I was able to update the text editor and the file shows up as modified. The key was to work with the ITextEditor and IDocumentProvider instead of a FileEditor.
Here's the updated code...
public Object execute(ExecutionEvent event) throws ExecutionException {
IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindowChecked(event);
IEditorPart editorPart = HandlerUtil.getActiveEditor(event);
if (editorPart instanceof ITextEditor ) {
ITextEditor editor = (ITextEditor)editorPart;
IDocumentProvider prov = editor.getDocumentProvider();
IDocument doc = prov.getDocument( editor.getEditorInput() );
String className = getClassName(doc.get());
ISelection sel = editor.getSelectionProvider().getSelection();
if (sel instanceof TextSelection ) {
TextSelection textSel = (TextSelection)sel;
String newText = generateBuilderText(className, textSel.getText());
try {
doc.replace(textSel.getOffset(), textSel.getLength(), newText);
} catch (Exception e) {
MessageDialog.openError(
window.getShell(),
"Generate Builder Error",
"An Exception has been thrown when attempting to replace "
+ "text in editor " + editor.getTitle() +
": " + e.getMessage());
}
}
}
return null;
}