Interface DataProvider<T,​F>

Method Detail

• isInMemory

  boolean isInMemory()

  Gets whether the DataProvider content all available in memory or does it use some external backend.

  Returns:

  true if all data is in memory; false if not

• size

  int size​(Query<T,​F> query)

  Gets the amount of data in this DataProvider.

  Parameters:

  query - query with sorting and filtering

  Returns:

  the size of the data provider

• fetch

  Stream<T> fetch​(Query<T,​F> query)

  Fetches data from this DataProvider using given query.

  Parameters:

  query - given query to request data

  Returns:

  the result of the query request: a stream of data objects, not null

• refreshItem

  void refreshItem​(T item)

  Refreshes the given item. This method should be used to inform all DataProviderListeners that an item has been updated or replaced with a new instance.

  For this to work properly, the item must either implement Object.equals(Object) and Object.hashCode() to consider both the old and the new item instances to be equal, or alternatively getId(Object) should be implemented to return an appropriate identifier.

  Parameters:

  item - the item to refresh

  See Also:

  getId(Object)

• refreshItem

  default void refreshItem​(T item,
                           boolean refreshChildren)

  Refreshes the given item and all of the children of the item as well.

  Parameters:

  item - the item to refresh

  refreshChildren - whether or not to refresh child items

  See Also:

  By default it just does a standard refreshItem, in a hierarchical DataProvider it is supposed to refresh all of the children as well in case 'refreshChildren' is true.

• refreshAll

  void refreshAll()

  Refreshes all data based on currently available data in the underlying provider.

• getId

  default Object getId​(T item)

  Gets an identifier for the given item. This identifier is used by the framework to determine equality between two items.

  Default is to use item itself as its own identifier. If the item has Object.equals(Object) and Object.hashCode() implemented in a way that it can be compared to other items, no changes are required.

  Note: This method will be called often by the Framework. It should not do any expensive operations.

  Parameters:

  item - the item to get identifier for; not null

  Returns:

  the identifier for given item; not null

• addDataProviderListener

  Registration addDataProviderListener​(DataProviderListener<T> listener)

  Adds a data provider listener. The listener is called when some piece of data is updated.

  The refreshAll() method fires DataChangeEvent each time when it's called. It allows to update UI components when user changes something in the underlying data.

  Parameters:

  listener - the data change listener, not null

  Returns:

  a registration for the listener

  See Also:

  refreshAll()

• withConvertedFilter

  default <C> DataProvider<T,​C> withConvertedFilter​(SerializableFunction<C,​F> filterConverter)

  Wraps this data provider to create a data provider that uses a different filter type. This can be used for adapting this data provider to a filter type provided by a Component such as ComboBox.

  For example receiving a String from ComboBox and making a Predicate based on it:

   DataProvider<Person, Predicate<Person>> dataProvider;
   // ComboBox uses String as the filter type
   DataProvider<Person, String> wrappedProvider = dataProvider
           .withConvertedFilter(filterText -> {
               Predicate<Person> predicate = person -> person.getName()
                       .startsWith(filterText);
               return predicate;
           });
   comboBox.setDataProvider(wrappedProvider);
   

  Type Parameters:

  C - the filter type that the wrapped data provider accepts; typically provided by a Component

  Parameters:

  filterConverter - callback that converts the filter in the query of the wrapped data provider into a filter supported by this data provider. Will only be called if the query contains a filter. Not null

  Returns:

  wrapped data provider, not null

• withConfigurableFilter

  default <Q,​C> ConfigurableFilterDataProvider<T,​Q,​C> withConfigurableFilter​(SerializableBiFunction<Q,​C,​F> filterCombiner)

  Wraps this data provider to create a data provider that supports programmatically setting a filter that will be combined with a filter provided through the query.

  Type Parameters:

  Q - the query filter type

  C - the configurable filter type

  Parameters:

  filterCombiner - a callback for combining and the configured filter with the filter from the query to get a filter to pass to the wrapped provider. Either parameter might be null, but the callback will not be invoked at all if both would be null. Not null.

  Returns:

  a data provider with a configurable filter, not null

  See Also:

  withConfigurableFilter(), ConfigurableFilterDataProvider.setFilter(Object)

• withConfigurableFilter

  default ConfigurableFilterDataProvider<T,​Void,​F> withConfigurableFilter()

  Wraps this data provider to create a data provider that supports programmatically setting a filter but no filtering through the query.

  Returns:

  a data provider with a configurable filter, not null

  See Also:

  withConfigurableFilter(SerializableBiFunction), ConfigurableFilterDataProvider.setFilter(Object)

• ofCollection

  static <T> ListDataProvider<T> ofCollection​(Collection<T> items)

  Creates a new data provider backed by a collection.

  The collection is used as-is. Changes in the collection will be visible via the created data provider. The caller should copy the collection if necessary.

  Type Parameters:

  T - the data item type

  Parameters:

  items - the collection of data, not null

  Returns:

  a new list data provider

• ofItems

  @SafeVarargs
  static <T> ListDataProvider<T> ofItems​(T... items)

  Creates a new data provider from the given items.

  The items are copied into a new backing list, so structural changes to the provided array will not be visible via the created data provider.

  Type Parameters:

  T - the data item type

  Parameters:

  items - the data items

  Returns:

  a new list data provider

• fromStream

  static <T> ListDataProvider<T> fromStream​(Stream<T> items)

  Creates a new data provider from the given stream. All items in the stream are eagerly collected to a list.

  This is a shorthand for using ofCollection(Collection) after collecting the items in the stream to a list with e.g. stream.collect(Collectors.toList));.

  Using big streams is not recommended, you should instead use a lazy data provider. See fromCallbacks(CallbackDataProvider.FetchCallback, CallbackDataProvider.CountCallback) or BackEndDataProvider for more info.

  Type Parameters:

  T - the data item type

  Parameters:

  items - a stream of data items, not null

  Returns:

  a new list data provider

• fromFilteringCallbacks

  static <T,​F> CallbackDataProvider<T,​F> fromFilteringCallbacks​(CallbackDataProvider.FetchCallback<T,​F> fetchCallback,
                                                                            CallbackDataProvider.CountCallback<T,​F> countCallback)

  Creates a new data provider that uses filtering callbacks for fetching and counting items from any backing store.

  The query that is passed to each callback may contain a filter value that is provided by the component querying for data.

  Type Parameters:

  T - data provider data type

  F - data provider filter type

  Parameters:

  fetchCallback - function that returns a stream of items from the back end for a query

  countCallback - function that returns the number of items in the back end for a query

  Returns:

  a new callback data provider

• fromCallbacks

  static <T> CallbackDataProvider<T,​Void> fromCallbacks​(CallbackDataProvider.FetchCallback<T,​Void> fetchCallback,
                                                              CallbackDataProvider.CountCallback<T,​Void> countCallback)

  Creates a new data provider that uses callbacks for fetching and counting items from any backing store.

  The query that is passed to each callback will not contain any filter values.

  Type Parameters:

  T - data provider data type

  Parameters:

  fetchCallback - function that returns a stream of items from the back end for a query

  countCallback - function that returns the number of items in the back end for a query

  Returns:

  a new callback data provider