title: Vaadin 7 Combo Box - how to populate and dropdown when text is typed?
body: <p>I have an app that has editors for various database records. These records are referencing each other. I'm developing a new custom data-aware component that is based on ComboBox:</p>
  
  <pre><code>public abstract class CustomDbLookupField&lt;T&gt; extends CustomField&lt;T&gt; implements Field&lt;T&gt; 
  </code></pre>
  
  <p>Here is what I want:</p>
  
  <ul>
  <li>the component looks like a combo box (I could do this easily)</li>
  <li>when the corresponding field has a row id value, then the component displays the textual representation of that referenced record (I could also do this)</li>
  <li>when the user starts typing text in the combobox, then I want to search for keywords in the database, and populate the combobox with those items, and let then</li>
  <li>drop down the combo box for him and et him select from the results</li>
  </ul>
  
  <p>I cannot seem to do the last two parts. I wanted to bind listener to the "text typed into combo box" event, but I cannot find any method for that. Moreover, I don't know how to get the text that was just typed in. I was trying this:</p>
  
  <pre><code>cmb.addListener(com.vaadin.event.FieldEvents.TextChangeEvent.class,target, method);
  </code></pre>
  
  <p>but I don't know what to pass for parameters target and method.</p>