Package com.vaadin.flow.data.provider.hierarchy

Interface HierarchicalDataProvider<T,F>

Type Parameters:
T - data type
F - filter type
All Superinterfaces:
DataProvider<T,F>, Serializable
All Known Subinterfaces:
BackEndHierarchicalDataProvider<T,F>, HierarchicalConfigurableFilterDataProvider<T,Q,C>
All Known Implementing Classes:
AbstractBackEndHierarchicalDataProvider, AbstractHierarchicalDataProvider, TreeDataProvider
public interface HierarchicalDataProvider<T,F> extends DataProvider<T,F>
A common interface for fetching hierarchical data from a data source, such as an in-memory collection or a backend database.
Since:
1.2
Author:
Vaadin Ltd

  • Method Details

    • size

      default int size(Query<T,F> query)
      Get the number of immediate child data items for the parent item returned by a given query.
      Specified by:
      size in interface DataProvider<T,F>
      Parameters:
      query - given query to request the count for
      Returns:
      the count of child data items for the data item HierarchicalQuery.getParent()
      Throws:
      IllegalArgumentException - if the query is not of type HierarchicalQuery

    • fetch

      default Stream<T> fetch(Query<T,F> query)
      Fetches data from this HierarchicalDataProvider using given query. Only the immediate children of HierarchicalQuery.getParent() will be returned.
      Specified by:
      fetch in interface DataProvider<T,F>
      Parameters:
      query - given query to request data with
      Returns:
      a stream of data objects resulting from the query
      Throws:
      IllegalArgumentException - if the query is not of type HierarchicalQuery

    • getChildCount

      int getChildCount(HierarchicalQuery<T,F> query)
      Get the number of immediate child data items for the parent item returned by a given query.
      Parameters:
      query - given query to request the count for
      Returns:
      the count of child data items for the data item HierarchicalQuery.getParent()

    • fetchChildren

      Stream<T> fetchChildren(HierarchicalQuery<T,F> query)
      Fetches data from this HierarchicalDataProvider using given query. Only the immediate children of HierarchicalQuery.getParent() will be returned.
      Parameters:
      query - given query to request data with
      Returns:
      a stream of data objects resulting from the query

    • hasChildren

      boolean hasChildren(T item)
      Check whether a given item has any children associated with it.
      Parameters:
      item - the item to check for children
      Returns:
      whether the given item has children

    • withConfigurableFilter

      default <Q, C> HierarchicalConfigurableFilterDataProvider<T,Q,C> withConfigurableFilter(SerializableBiFunction<Q,C,F> filterCombiner)
      Description copied from interface: DataProvider
      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.
      Specified by:
      withConfigurableFilter in interface DataProvider<T,F>
      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:

    • withConvertedFilter

      default <C> HierarchicalDataProvider<T,C> withConvertedFilter(SerializableFunction<C,F> filterConverter)
      Description copied from interface: DataProvider
      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);
      Specified by:
      withConvertedFilter in interface DataProvider<T,F>
      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 HierarchicalConfigurableFilterDataProvider<T,Void,F> withConfigurableFilter()
      Description copied from interface: DataProvider
      Wraps this data provider to create a data provider that supports programmatically setting a filter but no filtering through the query.
      Specified by:
      withConfigurableFilter in interface DataProvider<T,F>
      Returns:
      a data provider with a configurable filter, not null
      See Also: