SyntheticaFX Validation Overview / Quick Start

• Validator

  A Validator is a functional interface which returns true on validation success only.

  public interface Validator<T extends Node>{
    boolean isValid(T n);
  }
  

When exactly a Validator is called depends on the Validation.Type. Three different types are supported.
• MANUAL - Validation is triggered by calling Validator#revalidate()
• LAZY - Validation is triggered on focus lost
• EAGER - Validation is triggered on text/value change and focus lost

For the ease of use some installation methods are predefined in the Validation class.

• Validation

  The Validation class provides the Validation.Type and some convenient installation methods. Generally adding validation to a node is an easy task and can be done in a single line - see example below.

  TextField loginNameField = createTextField();
  Validation.installValidator(loginNameField, Validator.createEmptyValidator(loginNameField), Validation.Type.LAZY, Decorator.createWarningDecorator("Field can not be empty!"));
  //custom validator - minimum name length is 6
  //Validation.installValidator(loginNameField, n -> {return n.getText().length() > 5;}, Validation.Type.LAZY, Decorator.createWarningDecorator("Minimum length is 6!"));
  

• Decorator

  As a visual feedback of an invalid input a node can be displayed as decorator on top of the owner control. Generally any Node can be used as decorator. The Decorator class is a wrapper for the decorator node and allows you to specify some additional parameter where the decorator will appear in relation to the owner. The static method #createWarningDecorator(String) creates a warning icon with the specified text as tooltip. Instead or together with a decorator a style class name for the owner can be specified. The class name will be set as soon as the owner becomes invalid and has to be defined in your CSS file. Additionally the pseudo class :invalid is set on the owner node and allows you to define CSS highlighting for specific controls. In the screenshot below the red text color and the red borders are provided this way. The related CSS is part of the SyntheticaFXModena theme.

  

• Validity

  Each installation method returns a Validity object which represents the validation state of a control since the last validation check. Because Validity is a ObjectProperty<Boolean>, it can be simply bound to other properties. To generate bindings in a fluent style some convenience methods are already predefined. By default the property is initialized with null which also means that the related Validator hasn't been called so far. A Validity object can be updated any time by calling Validity#revalidate().

  TextField loginNameField = createTextField();
  Validity v1 = Validation.installValidator(loginNameField, ...);
  TextField emailField = createTextField();
  Validity v2 = Validation.installValidator(emailField, ...);
  Button button = new Button("Create Account");
  //button.disableProperty().bind(v1.and(v2).not());
  button.setOnAction(e -> {
        boolean allValid = v1.and(v2).get();
        System.out.println(allValid);
      });
  

See also