title: How to detect enter key press in vaadin TextArea
body: <p>I am using a vaadin TextArea as a rough console. The user can enter commands which should be executed when he presses the enter key. Is there a way to specify this with a listener on the TextArea?</p>
  
  <p>The closest thing I found is to use:</p>
  
  <pre><code>TextArea textArea = new TextArea();
  textArea.addTextChangeListener(this);
  textArea.setTextChangeEventMode(TextChangeEventMode.EAGER);
  </code></pre>
  
  <p>And handle the text change event:</p>
  
  <pre><code>@Override
  public void textChange(TextChangeEvent event) {
     System.out.println(event.getText());
  }
  </code></pre>
  
  <p>This is however triggered as soon as text has been entered in the TextArea. I would like to be notified only when the enter key has been pressed.</p>