Package org.apache.tapestry5

# Interface NullFieldStrategy

All Known Implementing Classes:
  `DefaultNullFieldStrategy`, `ZeroNullFieldStrategy`

public interface NullFieldStrategy
Defines a strategy, used by `Field` components such as `TextField`, to handle the case where either the server-side value to be sent (as a string) to the client, or the client-side string passed back up to the server, is null or blank.

See Also:
  - `NullFieldStrategySource`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `String`
  `replaceFromClient()`
  Provides a replacement value for a null or blank string passed from the client to the server as part of a form submission.
  `Object`
  `replaceToClient()`
  Provides a replacement value for null, when converting the server-side object to a client-side string.

- ## Method Details

  - ### replaceToClient

    Object replaceToClient()
    Provides a replacement value for null, when converting the server-side object to a client-side string. The replacement value, if non-null, will be passed to `Translator.toClient(Object)`.

  - ### replaceFromClient

    String replaceFromClient()
    Provides a replacement value for a null or blank string passed from the client to the server as part of a form submission. This replacement value will be passed to `Translator.parseClient(Field, String, String)` as if it were the value supplied by the user.
    Returns:
      replacement value (this must not be null)