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

Class 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 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

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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

        addIdentifierProviderChangeListener, equals, getIdentifierProvider, refreshAll, refreshItem, setIdentifierProvider, verifyDataProviderType

      • 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()

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

        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