title: How to create an ObservableBooleanValue from a boolean value
body: <p>Given I have a javafx input field with a validator on it (example taken from the JFoenix <a href="http://www.jfoenix.com/documentation.html#InputFields" rel="nofollow noreferrer">library</a>): </p>
  
  <pre><code>JFXTextField validationField = new JFXTextField();
  validationField.setPromptText("Your age");
  
  NumberValidator validator = new NumberValidator();
  validator.setMessage("Digits only!");    
  validationField.getValidators().add(validator);
  validationField.focusedProperty().addListener((o,oldVal,newVal)-&gt;{
      if(!newVal) validationField.validate();
  });
  </code></pre>
  
  <p>My goal is to enable/disable some button only if the validation on the text field returns true, however <code>validationField.validate()</code> returns a boolean instead of a ObservableBooleanValue.</p>
  
  <pre><code>BooleanBinding invalid = someOtherTextField.textProperty().isEmpty()
                  .or(!validationField.validate()); // invalid syntax                                 
  candidateButton.disableProperty().bind(invalid);
  </code></pre>
  
  <p>How do I create an ObservableBooleanValue from a validation of a text field?</p>