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

Class AbstractBackEndHierarchicalDataProvider<T,F>

java.lang.Object

com.vaadin.flow.data.provider.AbstractDataProvider<T,F>

com.vaadin.flow.data.provider.hierarchy.AbstractHierarchicalDataProvider<T,F>

com.vaadin.flow.data.provider.hierarchy.AbstractBackEndHierarchicalDataProvider<T,F>

Type Parameters:

T - data type

F - filter type

All Implemented Interfaces:

BackEndDataProvider<T,F>, DataProvider<T,F>, BackEndHierarchicalDataProvider<T,F>, HierarchicalDataProvider<T,F>, Serializable

public abstract class AbstractBackEndHierarchicalDataProvider<T,F>
extends AbstractHierarchicalDataProvider<T,F>
implements BackEndHierarchicalDataProvider<T,F>

Abstract base class for implementing BackEndHierarchicalDataProviders.

Since:

1.2

Author:

Vaadin Ltd

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.vaadin.flow.data.provider.hierarchy.HierarchicalDataProvider

HierarchicalDataProvider.HierarchyFormat

Constructor Summary

Constructors

Constructor	Description
AbstractBackEndHierarchicalDataProvider()

Method Summary

Modifier and Type	Method	Description
Stream<T>	fetchChildren(HierarchicalQuery<T,F> query)	Fetches children based on the given hierarchical query.
protected abstract Stream<T>	fetchChildrenFromBackEnd(HierarchicalQuery<T,F> query)	Fetches data from the back end using the given query.
boolean	isInMemory()	Gets whether the DataProvider content all available in memory or does it use some external backend.
void	setSortOrders(List<QuerySortOrder> sortOrders)	Sets a list of sort orders to use as the default sorting for this data provider.

Methods inherited from class com.vaadin.flow.data.provider.hierarchy.AbstractHierarchicalDataProvider

refreshItem, withConfigurableFilter, withConfigurableFilter, withConvertedFilter

Methods inherited from class com.vaadin.flow.data.provider.AbstractDataProvider

addDataProviderListener, addListener, fireEvent, refreshAll, refreshItem

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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

setSortOrder, setSortOrders

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

addDataProviderListener, getId, refreshAll, refreshItem, refreshItem

Methods inherited from interface com.vaadin.flow.data.provider.hierarchy.HierarchicalDataProvider

fetch, getChildCount, getDepth, getHierarchyFormat, getItemIndex, getParent, hasChildren, size, withConfigurableFilter, withConfigurableFilter, withConvertedFilter

Constructor Details

AbstractBackEndHierarchicalDataProvider

public AbstractBackEndHierarchicalDataProvider()

Method Details

fetchChildren

public Stream<T> fetchChildren(HierarchicalQuery<T,F> query)

Description copied from interface: HierarchicalDataProvider

Fetches children based on the given hierarchical query.

This method must be implemented in accordance with the selected hierarchy type, see HierarchicalDataProvider.getHierarchyFormat() and HierarchicalDataProvider.HierarchyFormat.

Specified by:

fetchChildren in interface HierarchicalDataProvider<T,F>

Parameters:

query - given query to request data with

Returns:

a stream of data objects for the parent item or the root level if the parent is null, must not contain null values

isInMemory

public boolean isInMemory()

Description copied from interface: DataProvider

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

Specified by:

isInMemory in interface BackEndDataProvider<T,F>

Specified by:

isInMemory in interface DataProvider<T,F>

Returns:

true if all data is in memory; false if not

setSortOrders

public void setSortOrders(List<QuerySortOrder> sortOrders)

Description copied from interface: BackEndDataProvider

Sets a list of sort orders to use as the default sorting for this data provider. This overrides the sorting set by any other method that manipulates the default sorting of this data provider.

The default sorting is used if the query defines no sorting. The default sorting is also used to determine the ordering of items that are considered equal by the sorting defined in the query.

Specified by:

setSortOrders in interface BackEndDataProvider<T,F>

Parameters:

sortOrders - a list of sort orders to set, not null

See Also:

• BackEndDataProvider.setSortOrder(QuerySortOrder)

fetchChildrenFromBackEnd

protected abstract Stream<T> fetchChildrenFromBackEnd(HierarchicalQuery<T,F> query)

Fetches data from the back end using the given query.

Parameters:

query - the query that defines sorting, filtering, paging and the parent item to fetch children from

Returns:

a stream of items matching the query

See Also:

• HierarchicalQuery