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Associated with the Form is an ValidationTracker that tracks all the provided user input and validation errors for every field in the form. The tracker can be provided to the Form via the Form's tracker parameter, but this is rarely necessary.

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In your own logic, it is possible to record your own errors. Form includes two different versions of method recordError(), one of which specifies a Field (an interface implemented by all form element components), and one of which is for "global" errors, unassociated with any particular field.

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Centralizing Validation with @Validate

The Validate annotation can take the place of the validate parameter of TextField, PasswordField, TextArea and other components. When the validate parameter is not bound, the component will check for the @Validate annotation and use its value as the validation definition.

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The TextField, PasswordField and TextArea components all have a translate parameter, a FieldTranslator object that is used to convert values on the server side to strings on the client side.

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The event handler may also throw ValidationException to indicate a value that can't be parsed.

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