com.vaadin.flow.data.provider

Class AbstractBackEndDataProvider<T,F>

java.lang.Object

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

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

Type Parameters:

T - data provider data type

F - data provider filter type

All Implemented Interfaces:

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

Direct Known Subclasses:

CallbackDataProvider

public abstract class AbstractBackEndDataProvider<T,F>
extends AbstractDataProvider<T,F>
implements BackEndDataProvider<T,F>

Abstract base class for implementing back end data providers.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
AbstractBackEndDataProvider()

Method Summary

Modifier and Type	Method and Description
Stream<T>	fetch(Query<T,F> query) Fetches data from this DataProvider using given query.
protected abstract Stream<T>	fetchFromBackEnd(Query<T,F> query) Fetches data from the back end using the given query.
void	setSortOrders(List<QuerySortOrder> sortOrders) Sets a list of sort orders to use as the default sorting for this data provider.
int	size(Query<T,F> query) Gets the amount of data in this DataProvider.
protected abstract int	sizeInBackEnd(Query<T,F> query) Counts the number of items available in the back end.

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

isInMemory, setSortOrder, setSortOrders

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

addDataProviderListener, fromCallbacks, fromFilteringCallbacks, fromStream, getId, ofCollection, ofItems, refreshAll, refreshItem, withConfigurableFilter, withConfigurableFilter, withConvertedFilter

Constructor Detail

AbstractBackEndDataProvider

public AbstractBackEndDataProvider()

Method Detail

fetch

public Stream<T> fetch(Query<T,F> query)

Description copied from interface: DataProvider

Fetches data from this DataProvider using given query.

Specified by:

fetch in interface DataProvider<T,F>

Parameters:

query - given query to request data

Returns:

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

size

public int size(Query<T,F> query)

Description copied from interface: DataProvider

Gets the amount of data in this DataProvider.

Specified by:

size in interface DataProvider<T,F>

Parameters:

query - query with sorting and filtering

Returns:

the size of the data provider

fetchFromBackEnd

protected abstract Stream<T> fetchFromBackEnd(Query<T,F> query)

Fetches data from the back end using the given query.

Parameters:

query - the query that defines sorting, filtering and paging for fetching the data

Returns:

a stream of items matching the query

sizeInBackEnd

protected abstract int sizeInBackEnd(Query<T,F> query)

Counts the number of items available in the back end.

Parameters:

query - the query that defines filtering to be used for counting the number of items

Returns:

the number of available items

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)