Interface DataSource<T>

Method Detail

• ensureAvailability

  void ensureAvailability​(int firstRowIndex,
                          int numberOfRows)

  Informs the data source that data for the given range is needed. A data source only has one active region at a time, so calling this method discards the previously set range.

  This method triggers lazy loading of data if necessary. The change handler registered using addDataChangeHandler(DataChangeHandler) is informed when new data has been loaded.

  After any possible lazy loading and updates are done, the change handler is informed that new data is available.

  Parameters:

  firstRowIndex - the index of the first needed row

  numberOfRows - the number of needed rows

• getRow

  T getRow​(int rowIndex)

  Retrieves the data for the row at the given index. If the row data is not available, returns null.

  This method does not trigger loading of unavailable data. ensureAvailability(int, int) should be used to signal what data will be needed.

  Parameters:

  rowIndex - the index of the row to retrieve data for

  Returns:

  data for the row; or null if no data is available

• size

  int size()

  Returns the number of rows in the data source.

  Returns:

  the current size of the data source

• addDataChangeHandler

  Registration addDataChangeHandler​(DataChangeHandler dataChangeHandler)

  Sets a data change handler to inform when data is updated, added or removed.

  Parameters:

  dataChangeHandler - the data change handler

  Returns:

  registration for removing the handler

• addDataChangeHandler

  default Registration addDataChangeHandler​(Consumer<Range> refreshMethod)

  Sets a simple data change handler for a widget without lazy loading. Refresh method should reset all the data in the widget.

  Parameters:

  refreshMethod - a method to refresh all data in the widget

  Returns:

  registration for removing the handler

• getHandle

  DataSource.RowHandle<T> getHandle​(T row)

  Gets a DataSource.RowHandle of a row object in the cache.

  Parameters:

  row - the row object for which to retrieve a row handle

  Returns:

  a non-null row handle of the given row object

• isWaitingForData

  boolean isWaitingForData()

  Checks whether this data source is currently waiting for more rows to become available.

  Returns:

  true if waiting for data; otherwise false

  Since:

  7.7.2