com.vaadin.flow.component.combobox.dataview

Class ComboBoxLazyDataView<T>

java.lang.Object

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

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

com.vaadin.flow.component.combobox.dataview.ComboBoxLazyDataView<T>

Type Parameters:

T - the type of the items in ComboBox

All Implemented Interfaces:

com.vaadin.flow.data.provider.DataView<T>, com.vaadin.flow.data.provider.LazyDataView<T>, Serializable

public class ComboBoxLazyDataView<T>
extends com.vaadin.flow.data.provider.AbstractLazyDataView<T>

Data view implementation for ComboBox with lazy data fetching. Provides information on the data and allows operations on it.

See Also:

Serialized Form

Field Summary

Fields inherited from class com.vaadin.flow.data.provider.AbstractDataView

component, dataProviderSupplier, NULL_IDENTIFIER_ERROR_MESSAGE, NULL_ITEM_ERROR_MESSAGE

Constructor Summary

Constructors

Constructor and Description
ComboBoxLazyDataView(com.vaadin.flow.data.provider.DataCommunicator<T> dataCommunicator, com.vaadin.flow.component.Component component) Creates a new lazy data view for ComboBox and verifies the passed data provider is compatible with this data view implementation.

Method Summary

Modifier and Type	Method and Description
com.vaadin.flow.shared.Registration	addItemCountChangeListener(com.vaadin.flow.component.ComponentEventListener<com.vaadin.flow.data.provider.ItemCountChangeEvent<?>> listener)
T	getItem(int index) Gets the item at the given index from the data available in the ComboBox's server-side.
Stream<T>	getItems() Gets the items available on the ComboBox's server-side.
void	setItemCountCallback(com.vaadin.flow.data.provider.CallbackDataProvider.CountCallback<T,String> callback) Sets a callback that the combo box uses to get the exact item count in the backend.
void	setItemCountEstimate(int itemCountEstimate)
void	setItemCountFromDataProvider()
void	setItemCountUnknown()

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

getDataCommunicator, getItemCountEstimate, getItemCountEstimateIncrease, getSupportedDataProviderType, setItemCountEstimateIncrease

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

equals, getIdentifierProvider, refreshAll, refreshItem, setIdentifierProvider, verifyDataProviderType

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.DataView

refreshAll, refreshItem, setIdentifierProvider

Constructor Detail

ComboBoxLazyDataView

public ComboBoxLazyDataView(com.vaadin.flow.data.provider.DataCommunicator<T> dataCommunicator,
                            com.vaadin.flow.component.Component component)

Creates a new lazy data view for ComboBox and verifies the passed data provider is compatible with this data view implementation.

Parameters:

dataCommunicator - the data communicator of the component

component - the ComboBox

Method Detail

setItemCountCallback

public void setItemCountCallback(com.vaadin.flow.data.provider.CallbackDataProvider.CountCallback<T,String> callback)

Sets a callback that the combo box uses to get the exact item count in the backend. Use this when it is cheap to get the exact item count and it is desired that the user sees the "full scrollbar size".

The given callback will be queried for the count instead of the data provider DataProvider.size(Query) method when the component has a distinct data provider set with HasLazyDataView.setItems(BackEndDataProvider).

Parameters:

callback - the callback to use for determining item count in the backend, not null

See Also:

setItemCountFromDataProvider(), setItemCountUnknown()

setItemCountFromDataProvider

public void setItemCountFromDataProvider()

Specified by:

setItemCountFromDataProvider in interface com.vaadin.flow.data.provider.LazyDataView<T>

Overrides:

setItemCountFromDataProvider in class com.vaadin.flow.data.provider.AbstractLazyDataView<T>

setItemCountEstimate

public void setItemCountEstimate(int itemCountEstimate)

Calling this method will clear any previously set count callback setItemCountCallback(CallbackDataProvider.CountCallback).

Specified by:

setItemCountEstimate in interface com.vaadin.flow.data.provider.LazyDataView<T>

Overrides:

setItemCountEstimate in class com.vaadin.flow.data.provider.AbstractLazyDataView<T>

setItemCountUnknown

public void setItemCountUnknown()

Calling this method will clear any previously set count callback setItemCountCallback(CallbackDataProvider.CountCallback).

Specified by:

setItemCountUnknown in interface com.vaadin.flow.data.provider.LazyDataView<T>

Overrides:

setItemCountUnknown in class com.vaadin.flow.data.provider.AbstractLazyDataView<T>

addItemCountChangeListener

public com.vaadin.flow.shared.Registration addItemCountChangeListener(com.vaadin.flow.component.ComponentEventListener<com.vaadin.flow.data.provider.ItemCountChangeEvent<?>> listener)

Combo box fires ItemCountChangeEvent and notifies all the listeners added by this method, if the items count changed, for instance, due to fetching more items while scrolling with unknown item count.

ComboBox's client-side filter change won't fire ItemCountChangeEvent, since it doesn't change the item count on the server-side, but only makes it easier for users to search through the items in the UI.

Specified by:

addItemCountChangeListener in interface com.vaadin.flow.data.provider.DataView<T>

Overrides:

addItemCountChangeListener in class com.vaadin.flow.data.provider.AbstractDataView<T>

getItem

public T getItem(int index)

Gets the item at the given index from the data available in the ComboBox's server-side.

This method does not take into account the ComboBox client-side filtering, since it doesn't change the item count on the server-side, but only makes it easier for users to search through the items in the UI.

Specified by:

getItem in interface com.vaadin.flow.data.provider.DataView<T>

Overrides:

getItem in class com.vaadin.flow.data.provider.AbstractLazyDataView<T>

Parameters:

index - item index number

Returns:

item on index

Throws:

IndexOutOfBoundsException - requested index is outside of the data set

getItems

public Stream<T> getItems()

Gets the items available on the ComboBox's server-side.

This method does not take into account the ComboBox client-filtering, since it doesn't change the item count on the server-side, but only makes it easier for users to search through the items in the UI.

Specified by:

getItems in interface com.vaadin.flow.data.provider.DataView<T>

Overrides:

getItems in class com.vaadin.flow.data.provider.AbstractLazyDataView<T>

Returns:

items available on the server-side