Input Prompt Pattern in GWT

For a GWT project I'm working on, I've reached a point where I wanted to apply input prompts to a text box; this doesn't seem to be something that's built in to the basic GWT framework, or an easily-located extension. For that matter, I couldn't find anyone who'd done it and blogged about it, although it might be that they've used different terminology.

I thought it was worth a quick experiment to see how easy they would be to apply, and this is what I came up with:

package com.codiform.gwt.widget;

import com.google.gwt.event.dom.client.BlurEvent;
import com.google.gwt.event.dom.client.BlurHandler;
import com.google.gwt.event.dom.client.FocusEvent;
import com.google.gwt.event.dom.client.FocusHandler;

public class InputPrompt implements BlurHandler, FocusHandler {

 private String promptText;
 
 public InputPrompt( String text, TextBox... inputs ) {
  this.promptText = text;
  for( TextBox item : inputs ) {
   apply( item );
  }
 }

 public void apply( TextBox input ) {
  input.addBlurHandler( this );
  input.addFocusHandler( this );
  applyPrompt( input );
 }

 public void onBlur( BlurEvent event ) {
  TextBox blurred = (TextBox) event.getSource();
  applyPrompt( blurred );
 }

 private void applyPrompt( TextBox input ) {
  if( input.getText().isEmpty() ) {
   input.setText( promptText );
   input.addStyleName( "inputPrompt" ); 
  }
 }

 public void onFocus( FocusEvent event ) {
  TextBox focused = (TextBox) event.getSource();
  if( promptText.equals( focused.getText() ) ) {
   focused.setText( "" );
   focused.removeStyleName( "inputPrompt" ); 
  }
 }
}

The final version has some project-specific tweaks (interface for the textbox to make this code testable with mocks, a style name in the project namespace), but for the most part the above code seems to do the trick well and I'll be applying it shortly.