com.vaadin.flow.data.provider

Class AbstractDataView<T>

java.lang.Object

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

Type Parameters:

T - data type

All Implemented Interfaces:

DataView<T>, Serializable

Direct Known Subclasses:

AbstractLazyDataView, AbstractListDataView, CheckboxGroupDataView, ComboBoxDataView, GridDataView, ListBoxDataView, RadioButtonGroupDataView, SelectDataView

public abstract class AbstractDataView<T>
extends Object
implements DataView<T>

Abstract data view implementation which handles parts that apply for any type of data.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected Component	component
protected SerializableSupplier<? extends DataProvider<T,?>>	dataProviderSupplier
protected static String	NULL_IDENTIFIER_ERROR_MESSAGE
protected static String	NULL_ITEM_ERROR_MESSAGE

Constructor Summary

Constructors

Constructor and Description
AbstractDataView(SerializableSupplier<? extends DataProvider<T,?>> dataProviderSupplier, Component component) Creates a new instance of AbstractDataView subclass and verifies the passed data provider is compatible with this data view implementation.

Method Summary

Modifier and Type	Method and Description
Registration	addItemCountChangeListener(ComponentEventListener<ItemCountChangeEvent<?>> listener) Add an item count change listener that is fired when the item count changes.
protected boolean	equals(T item, T compareTo)
protected IdentifierProvider<T>	getIdentifierProvider()
Stream<T>	getItems() Get the full data available to the component.
protected abstract Class<?>	getSupportedDataProviderType() Returns supported DataProvider type for this DataView.
void	refreshAll() Notifies the component that all the items should be refreshed.
void	refreshItem(T item) Notifies the component that the item has been updated and thus should be refreshed.
void	setIdentifierProvider(IdentifierProvider<T> identifierProvider) Sets an identifier provider, which returns an identifier for the given item.
protected void	verifyDataProviderType(Class<?> dataProviderType) Verifies an obtained DataProvider type is appropriate for current Data View type.

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

getItem

Field Detail

NULL_ITEM_ERROR_MESSAGE

protected static final String NULL_ITEM_ERROR_MESSAGE

See Also:

Constant Field Values

NULL_IDENTIFIER_ERROR_MESSAGE

protected static final String NULL_IDENTIFIER_ERROR_MESSAGE

See Also:

Constant Field Values

dataProviderSupplier

protected SerializableSupplier<? extends DataProvider<T,?>> dataProviderSupplier

component

protected Component component

Constructor Detail

AbstractDataView

public AbstractDataView(SerializableSupplier<? extends DataProvider<T,?>> dataProviderSupplier,
                        Component component)

Creates a new instance of AbstractDataView subclass and verifies the passed data provider is compatible with this data view implementation.

Parameters:

dataProviderSupplier - supplier from which the DataProvider can be gotten

component - the component that the dataView is bound to

Method Detail

addItemCountChangeListener

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

Description copied from interface: DataView

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.

Specified by:

addItemCountChangeListener in interface DataView<T>

Parameters:

listener - item count change listener to register

Returns:

registration for removing the listener

getSupportedDataProviderType

protected abstract Class<?> getSupportedDataProviderType()

Returns supported DataProvider type for this DataView.

Returns:

supported data provider type

verifyDataProviderType

protected final void verifyDataProviderType(Class<?> dataProviderType)

Verifies an obtained DataProvider type is appropriate for current Data View type.

Parameters:

dataProviderType - data provider type to be verified

Throws:

IllegalStateException - if data provider type is incompatible with data view type

getItems

public Stream<T> getItems()

Description copied from interface: DataView

Get the full data available to the component. Data is filtered and sorted the same way as in the component.

Specified by:

getItems in interface DataView<T>

Returns:

filtered and sorted data set

refreshItem

public void refreshItem(T item)

Description copied from interface: DataView

Notifies the component that the item has been updated and thus should be refreshed.

For this to work properly, the item must either implement Object.equals(Object) and Object.hashCode() to consider both the old and the new item instances to be equal, or alternatively use the DataView.setIdentifierProvider(IdentifierProvider) to set an appropriate item's identifier.

This method delegates the update to DataProvider.refreshItem(Object).

Specified by:

refreshItem in interface DataView<T>

Parameters:

item - item containing updated state

See Also:

DataView.setIdentifierProvider(IdentifierProvider)

refreshAll

public void refreshAll()

Description copied from interface: DataView

Notifies the component that all the items should be refreshed.

Specified by:

refreshAll in interface DataView<T>

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>

Parameters:

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

getIdentifierProvider

protected IdentifierProvider<T> getIdentifierProvider()

equals

protected boolean equals(T item,
                         T compareTo)