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 Summary

Modifier and Type	Method and Description
default Stream<T>	fetch(Query<T,F> query) Fetches data from this HierarchicalDataProvider using given query.
Stream<T>	fetchChildren(HierarchicalQuery<T,F> query) Fetches data from this HierarchicalDataProvider using given query.
int	getChildCount(HierarchicalQuery<T,F> query) Get the number of immediate child data items for the parent item returned by a given query.
boolean	hasChildren(T item) Check whether a given item has any children associated with it.
default int	size(Query<T,F> query) Get the number of immediate child data items for the parent item returned by a given query.
default HierarchicalConfigurableFilterDataProvider<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.
default <Q,C> HierarchicalConfigurableFilterDataProvider<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.
default <C> HierarchicalDataProvider<T,C>	withConvertedFilter(SerializableFunction<C,F> filterConverter) Wraps this data provider to create a data provider that uses a different filter type.

Methods inherited from interface com.vaadin.flow.data.provider.DataProvider

addDataProviderListener, fromCallbacks, fromFilteringCallbacks, fromStream, getId, isInMemory, ofCollection, ofItems, refreshAll, refreshItem, refreshItem

Method Detail

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:

DataProvider.withConfigurableFilter(), ConfigurableFilterDataProvider.setFilter(Object)

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:

DataProvider.withConfigurableFilter(SerializableBiFunction), ConfigurableFilterDataProvider.setFilter(Object)