com.vaadin.flow.data.provider

Class DataCommunicator<T>

java.lang.Object

com.vaadin.flow.data.provider.DataCommunicator<T>

Type Parameters:

T - the bean type

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

HierarchicalDataCommunicator

public class DataCommunicator<T>
extends Object
implements Serializable

DataProvider base class. This class is the base for all DataProvider communication implementations. It uses data generators (BiFunctions) to write JsonObjects representing each data object to be sent to the client-side.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
DataCommunicator(DataGenerator<T> dataGenerator, ArrayUpdater arrayUpdater, SerializableConsumer<elemental.json.JsonArray> dataUpdater, StateNode stateNode) Creates a new instance.

Method Summary

Modifier and Type	Method and Description
void	confirmUpdate(int updateId) Confirm update with the given updateId.
protected Stream<T>	fetchFromProvider(int offset, int limit) Fetches a list of items from the DataProvider.
List<QuerySortOrder>	getBackEndSorting() Returns the QuerySortOrder to use with backend sorting.
DataProvider<T,?>	getDataProvider() Gets the current data provider from this DataCommunicator.
protected int	getDataProviderSize() Getter method for finding the size of DataProvider.
protected Object	getFilter() Get the object used for filtering in this data communicator.
SerializableComparator<T>	getInMemorySorting() Returns the Comparator to use with in-memory sorting.
DataKeyMapper<T>	getKeyMapper() Gets the DataKeyMapper used by this DataCommunicator.
void	refresh(T data) Informs the DataCommunicator that a data object has been updated.
void	reset() Resets all the data.
void	setBackEndSorting(List<QuerySortOrder> sortOrder) Sets the QuerySortOrders to use with backend sorting.
<F> SerializableConsumer<F>	setDataProvider(DataProvider<T,F> dataProvider, F initialFilter) Sets the current data provider for this DataCommunicator.
void	setInMemorySorting(SerializableComparator<T> comparator) Sets the Comparator to use with in-memory sorting.
protected void	setKeyMapper(DataKeyMapper<T> keyMapper) Sets the DataKeyMapper used in this DataCommunicator.
void	setRequestedRange(int start, int length) Sets the requested range of data to be sent.

Methods inherited from class java.lang.Object

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

Constructor Detail

DataCommunicator

public DataCommunicator(DataGenerator<T> dataGenerator,
                        ArrayUpdater arrayUpdater,
                        SerializableConsumer<elemental.json.JsonArray> dataUpdater,
                        StateNode stateNode)

Creates a new instance.

Parameters:

dataGenerator - the data generator function

arrayUpdater - array updater strategy

dataUpdater - data updater strategy

stateNode - the state node used to communicate for

Method Detail

setRequestedRange

public void setRequestedRange(int start,
                              int length)

Sets the requested range of data to be sent.

Parameters:

start - the start of the requested range

length - the end of the requested range

reset

public void reset()

Resets all the data.

It effectively resends all available data.

refresh

public void refresh(T data)

Informs the DataCommunicator that a data object has been updated.

Parameters:

data - updated data object; not null

confirmUpdate

public void confirmUpdate(int updateId)

Confirm update with the given updateId.

Parameters:

updateId - the update identifier

getDataProvider

public DataProvider<T,?> getDataProvider()

Gets the current data provider from this DataCommunicator.

Returns:

the data provider

setDataProvider

public <F> SerializableConsumer<F> setDataProvider(DataProvider<T,F> dataProvider,
                                                   F initialFilter)

Sets the current data provider for this DataCommunicator.

The returned consumer can be used to set some other filter value that should be included in queries sent to the data provider. It is only valid until another data provider is set.

Type Parameters:

F - the filter type

Parameters:

dataProvider - the data provider to set, not null

initialFilter - the initial filter value to use, or null to not use any initial filter value

Returns:

a consumer that accepts a new filter value to use

getKeyMapper

public DataKeyMapper<T> getKeyMapper()

Gets the DataKeyMapper used by this DataCommunicator. Key mapper can be used to map keys sent to the client-side back to their respective data objects.

Returns:

key mapper

setKeyMapper

protected void setKeyMapper(DataKeyMapper<T> keyMapper)

Sets the DataKeyMapper used in this DataCommunicator. Key mapper can be used to map keys sent to the client-side back to their respective data objects.

Parameters:

keyMapper - the keyMapper

setInMemorySorting

public void setInMemorySorting(SerializableComparator<T> comparator)

Sets the Comparator to use with in-memory sorting.

Parameters:

comparator - comparator used to sort data

getInMemorySorting

public SerializableComparator<T> getInMemorySorting()

Returns the Comparator to use with in-memory sorting.

Returns:

comparator used to sort data

setBackEndSorting

public void setBackEndSorting(List<QuerySortOrder> sortOrder)

Sets the QuerySortOrders to use with backend sorting.

Parameters:

sortOrder - list of sort order information to pass to a query

getBackEndSorting

public List<QuerySortOrder> getBackEndSorting()

Returns the QuerySortOrder to use with backend sorting.

Returns:

an unmodifiable list of sort order information to pass to a query

getDataProviderSize

protected int getDataProviderSize()

Getter method for finding the size of DataProvider. Can be overridden by a subclass that uses a specific type of DataProvider and/or query.

Returns:

the size of data provider with current filter

getFilter

protected Object getFilter()

Get the object used for filtering in this data communicator.

Returns:

the filter object of this data communicator

fetchFromProvider

protected Stream<T> fetchFromProvider(int offset,
                                      int limit)

Fetches a list of items from the DataProvider.

Parameters:

offset - the starting index of the range

limit - the max number of results

Returns:

the list of items in given range