Package com.vaadin.flow.component.combobox.dataview

Class ComboBoxListDataView<T>

java.lang.Object

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

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

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

Type Parameters:

T - the type of the items in ComboBox

All Implemented Interfaces:

DataView<T>, ListDataView<T,AbstractListDataView<T>>, Serializable

public class ComboBoxListDataView<T>
extends AbstractListDataView<T>

Data view implementation for ComboBox with in-memory list data. 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	Description
ComboBoxListDataView(DataCommunicator<T> dataCommunicator, ComboBoxBase<?,T,?> comboBox, SerializableBiConsumer<SerializablePredicate<T>,SerializableComparator<T>> filterOrSortingChangedCallback)	Creates a new instance of ComboBox in-memory data view and verifies the passed data provider is compatible with this data view implementation.

Method Summary

Modifier and Type	Method	Description
ComboBoxListDataView<T>	addFilter(SerializablePredicate<T> filter)	Adds a filter to be applied to all queries.
Registration	addItemCountChangeListener(ComponentEventListener<ItemCountChangeEvent<?>> listener)	Add an item count change listener that is fired when the item count changes.
int	getItemCount()	Get the full item count with filters if any set.
Stream<T>	getItems()	Gets the items available on the ComboBox's server-side.
ComboBoxListDataView<T>	removeFilters()	Removes all in-memory filters set or added.
ComboBoxListDataView<T>	setFilter(SerializablePredicate<T> filter)	Sets a filter to be applied to the data.
void	setIdentifierProvider(IdentifierProvider<T> identifierProvider)	Sets an identifier provider, which returns an identifier for the given item.

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

addItem, addItemAfter, addItemBefore, addItems, addItemsAfter, addItemsBefore, addSortComparator, addSortOrder, contains, getDataProvider, getItem, getNextItem, getPreviousItem, getSupportedDataProviderType, removeItem, removeItems, removeSorting, setSortComparator, setSortOrder, validateItemIndex

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

addIdentifierProviderChangeListener, equals, getIdentifierProvider, getItemIndex, getItemIndex, refreshAll, refreshItem, verifyDataProviderType, 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

getItemIndex, refreshAll, refreshItem

Constructor Details

ComboBoxListDataView

public ComboBoxListDataView(DataCommunicator<T> dataCommunicator,
 ComboBoxBase<?,T,?> comboBox,
 SerializableBiConsumer<SerializablePredicate<T>,SerializableComparator<T>> filterOrSortingChangedCallback)

Creates a new instance of ComboBox in-memory data view and verifies the passed data provider is compatible with this data view implementation.

Parameters:

dataCommunicator - the data communicator of the ComboBox, not null

comboBox - the ComboBox component, not null

filterOrSortingChangedCallback - callback, which is being invoked when the ComboBox's filtering or sorting changes, not null

Method Details

getItems

public Stream<T> getItems()

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

Data is sorted the same way as in the ComboBox, but it 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. Only the server-side filtering considered, which is set by: setFilter(SerializablePredicate) or addFilter(SerializablePredicate).

Specified by:

getItems in interface DataView<T>

Overrides:

getItems in class AbstractListDataView<T>

Returns:

filtered and sorted items available in server-side

getItemCount

public int getItemCount()

Get the full item count with filters if any set. As the item count might change at any point, it is recommended to add a listener with the DataView.addItemCountChangeListener(ComponentEventListener) method instead to get notified when the item count has changed.

This method takes into account only the server-side filtering, which is set by: setFilter(SerializablePredicate) or addFilter(SerializablePredicate). ComboBox's client-side filter is not considered, 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:

getItemCount in interface ListDataView<T,AbstractListDataView<T>>

Overrides:

getItemCount in class AbstractListDataView<T>

Returns:

filtered item count

See Also:

• DataView.addItemCountChangeListener(ComponentEventListener)

setIdentifierProvider

public void setIdentifierProvider(IdentifierProvider<T> identifierProvider)

Description copied from interface: DataView

Sets an identifier provider, which returns an identifier for the given item. The identifier is used for comparing the equality of items. Usage example: dataView.setIdentifiedProvider(Item::getId);.

Specified by:

setIdentifierProvider in interface DataView<T>

Overrides:

setIdentifierProvider in class AbstractDataView<T>

Parameters:

identifierProvider - function that returns the non-null identifier for a given item

addItemCountChangeListener

public Registration addItemCountChangeListener(ComponentEventListener<ItemCountChangeEvent<?>> listener)

Add an item count change listener that is fired when the item count changes. This can happen for instance when filtering the items.

Item count change listener is bound to the component and will be retained even if the data changes by setting of a new items or DataProvider to component.

NOTE: when the component supports lazy loading (implements HasLazyDataView) and a count callback has not been provided, an estimate of the item count is used and increased until the actual count has been reached. When the estimate is used, the event is fired with the ItemCountChangeEvent.isItemCountEstimated() returning true.

Combo box fires ItemCountChangeEvent and notifies all the listeners added by this method, if the items count changed due to adding or removing an item(s), or by changing the server-side filtering with setFilter(SerializablePredicate) or addFilter(SerializablePredicate).

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 DataView<T>

Overrides:

addItemCountChangeListener in class AbstractDataView<T>

Parameters:

listener - item count change listener to register

Returns:

registration for removing the listener

addFilter

public ComboBoxListDataView<T> addFilter(SerializablePredicate<T> filter)

Adds a filter to be applied to all queries. The filter will be used in addition to any filter that has been set or added previously through setFilter(com.vaadin.flow.function.SerializablePredicate<T>) or addFilter(com.vaadin.flow.function.SerializablePredicate<T>). This filter is applied to data set permanently until it's changed through setFilter(com.vaadin.flow.function.SerializablePredicate<T>) or removeFilters(), in contrary with the client-side filter that can be typed in by user and does not modify the data set on server-side, but only defines which items are shown for a single request and erases on drop down close.

This filter is bound to the component. Thus, any other component using the same DataProvider object would not be affected by setting a filter through data view of another component. A filter set by this method won't be retained when a new DataProvider is set to the component.

Specified by:

addFilter in interface ListDataView<T,AbstractListDataView<T>>

Overrides:

addFilter in class AbstractListDataView<T>

Parameters:

filter - the filter to add, not null

Returns:

ComboBoxListDataView instance

See Also:

• setFilter(SerializablePredicate)
• removeFilters()

removeFilters

public ComboBoxListDataView<T> removeFilters()

Removes all in-memory filters set or added.

Specified by:

removeFilters in interface ListDataView<T,AbstractListDataView<T>>

Overrides:

removeFilters in class AbstractListDataView<T>

Returns:

ComboBoxListDataView instance

See Also:

• addFilter(SerializablePredicate)
• setFilter(SerializablePredicate)

setFilter

public ComboBoxListDataView<T> setFilter(SerializablePredicate<T> filter)

Sets a filter to be applied to the data. The filter replaces any filter that has been set or added previously. null will clear all filters. This filter is applied to data set permanently until it's changed through setFilter(com.vaadin.flow.function.SerializablePredicate<T>) or removeFilters(), in contrary with the client-side filter that can be typed in by user and does not modify the data set on server-side, but only defines which items are shown for a single request and erases on drop down close.

This filter is bound to the component. Thus, any other component using the same DataProvider object would not be affected by setting a filter through data view of another component. A filter set by this method won't be retained when a new DataProvider is set to the component.

Specified by:

setFilter in interface ListDataView<T,AbstractListDataView<T>>

Overrides:

setFilter in class AbstractListDataView<T>

Parameters:

filter - filter to be set, or null to clear any previously set filters

Returns:

ComboBoxListDataView instance

See Also:

• addFilter(SerializablePredicate)
• removeFilters()