Vaadin Framework 8.4.0.alpha2

Vaadin Framework 8.4.0.alpha2 is a pre-release for evaluating a number of new features and bug fixes. The API in this alpha version is not considered final and may change based on user feedback.

Enhancements in Vaadin Framework 8.4

• ComboBox has a better new item handling implementation with NewItemProvider.
• Binding APIs have been improved to allow more advanced use.
• New ReadOnlyHasValue wrapper class for easy implementation of new HasValues for Binder.
• Built-in StringTo converters now have option to use ErrorMessageProvider.
• Grid headers and footers now support tooltips.
• Added Tree and TreeGrid recursive expand and collapse methods.
• MenuBar items can now be used to start downloads.

Incompatible or Behavior-altering Changes in 8.4

• Date range limits in AbstractDateFieldState are now Strings instead of Dates, some client-side method signatures were changed
• BrowserResizeListener is called lazily during the resize (previously on each and every even browser fired, causing potentially hundreds of server visits per window resize).
• ItemClickEvent for Grid now takes an additional row index parameter.
• AbstractStringToNumberConverter method getErrorMessage now requires ValueContext as a paremeter.
• Class hierarchy of BrowserWindowOpenerConnector and FileDownloaderConnector has changed.