com.vaadin.flow.component.select

Class Select<T>

java.lang.Object

com.vaadin.flow.component.Component

com.vaadin.flow.component.AbstractField<C,T>

com.vaadin.flow.component.AbstractSinglePropertyField<R,T>

com.vaadin.flow.component.select.generated.GeneratedVaadinSelect<Select<T>,T>

com.vaadin.flow.component.select.Select<T>

Type Parameters:

T - the type of the items for the select

All Implemented Interfaces:

AttachNotifier, BlurNotifier<Select<T>>, DetachNotifier, Focusable<Select<T>>, FocusNotifier<Select<T>>, HasComponents, HasElement, HasEnabled, HasSize, HasStyle, HasValidation, HasValue<AbstractField.ComponentValueChangeEvent<Select<T>,T>,T>, HasValueAndElement<AbstractField.ComponentValueChangeEvent<Select<T>,T>,T>, HasDataProvider<T>, HasItems<T>, HasItemsAndComponents<T>, SingleSelect<Select<T>,T>, Serializable

@JsModule(value="./selectConnector.js")
public class Select<T>
extends GeneratedVaadinSelect<Select<T>,T>
implements HasDataProvider<T>, HasItemsAndComponents<T>, HasSize, HasValidation, SingleSelect<Select<T>,T>

A customizable drop-down select component similar to a native browser select.

This is a server side Java integration for <vaadin-select> web component.

For usage examples, see the demo in vaadin.com.

Author:

Vaadin Ltd.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.vaadin.flow.component.select.generated.GeneratedVaadinSelect

GeneratedVaadinSelect.InvalidChangeEvent<R extends GeneratedVaadinSelect<R,?>>, GeneratedVaadinSelect.OpenedChangeEvent<R extends GeneratedVaadinSelect<R,?>>

Nested classes/interfaces inherited from class com.vaadin.flow.component.AbstractField

AbstractField.ComponentValueChangeEvent<C extends Component,V>

Nested classes/interfaces inherited from interface com.vaadin.flow.data.binder.HasItemsAndComponents

HasItemsAndComponents.ItemComponent<T>

Nested classes/interfaces inherited from interface com.vaadin.flow.component.HasValue

HasValue.ValueChangeEvent<V>, HasValue.ValueChangeListener<E extends HasValue.ValueChangeEvent<?>>

Nested classes/interfaces inherited from interface com.vaadin.flow.component.BlurNotifier

BlurNotifier.BlurEvent<C extends Component>

Nested classes/interfaces inherited from interface com.vaadin.flow.component.FocusNotifier

FocusNotifier.FocusEvent<C extends Component>

Field Summary

Fields

Modifier and Type	Field and Description
static String	LABEL_ATTRIBUTE

Constructor Summary

Constructors

Constructor and Description
Select() Constructs a select.
Select(T... items) Constructs a select with the given items.

Method Summary

Modifier and Type	Method and Description
void	add(Component... components) Adds the given components as children of this component.
void	addComponentAsFirst(Component component) Adds the given component as the first child of this component.
void	addComponentAtIndex(int index, Component component) Adds the given component as child of this component at the specific index.
void	addComponents(T afterItem, Component... components) Adds the components after the given item.
void	addToPrefix(Component... components) Adds the given components as children of this component at the slot 'prefix'.
Stream<Component>	getChildren() Gets the child components of this component.
DataProvider<T,?>	getDataProvider() Gets the data provider.
String	getEmptySelectionCaption()
String	getErrorMessage() Gets the error message to show to the user on invalid selection
SerializablePredicate<T>	getItemEnabledProvider() Returns the item enabled predicate.
ItemLabelGenerator<T>	getItemLabelGenerator() Gets the item label generator.
ComponentRenderer<? extends Component,T>	getItemRenderer() Returns the item component renderer.
String	getLabel() Gets the string for the label element.
String	getPlaceholder() Gets the placeholder hint set for the user.
protected boolean	hasValidValue() Checks whether the element property has a value that can be converted to the model type.
boolean	isAutofocus() Gets whether this select has been set to autofocus when the page loads.
boolean	isEmptySelectionAllowed() Returns whether the user is allowed to select nothing.
boolean	isInvalid() Gets whether the select is currently in invalid state.
boolean	isRequiredIndicatorVisible() Checks whether the required indicator is visible.
protected void	onAttach(AttachEvent attachEvent) Called when the component is attached to a UI.
void	onEnabledStateChanged(boolean enabled) Handle component enable state when the enabled state changes.
void	prependComponents(T beforeItem, Component... components) Adds the components before the given item.
void	remove(Component... components) Removes the given child components from this component.
void	removeAll() Removes all child components that are not items.
void	setAutofocus(boolean autofocus) Sets the select to have focus when the page loads.
void	setDataProvider(DataProvider<T,?> dataProvider) Sets the data provider for this listing.
void	setEmptySelectionAllowed(boolean emptySelectionAllowed) Sets whether the user is allowed to select nothing.
void	setEmptySelectionCaption(String emptySelectionCaption) Sets the empty selection caption when setEmptySelectionAllowed(boolean) has been enabled.
void	setErrorMessage(String errorMessage) Sets the error message to show to the user on invalid selection.
void	setInvalid(boolean invalid) Sets the select to show as invalid state and display error message.
void	setItemEnabledProvider(SerializablePredicate<T> itemEnabledProvider) Sets the item enabled predicate for this select.
void	setItemLabelGenerator(ItemLabelGenerator<T> itemLabelGenerator) Sets the item label generator.
void	setLabel(String label) Sets the string for the label element.
void	setPlaceholder(String placeholder) Sets the placeholder hint for the user.
void	setRenderer(ComponentRenderer<? extends Component,T> renderer) Sets the item renderer for this select group.
void	setRequiredIndicatorVisible(boolean requiredIndicatorVisible) Sets the required indicator visible or not.
void	setTextRenderer(ItemLabelGenerator<T> itemLabelGenerator) Convenience setter for creating a TextRenderer from the given function that converts the item to a string.

Methods inherited from class com.vaadin.flow.component.select.generated.GeneratedVaadinSelect

addInvalidChangeListener, addOpenedChangeListener, getErrorMessageString, getLabelString, getNameString, getPlaceholderString, isAutofocusBoolean, isDisabledBoolean, isInvalidBoolean, isOpenedBoolean, isReadonlyBoolean, isRequiredBoolean, render, setDisabled, setName, setOpened, setReadonly, setRequired, validate

Methods inherited from class com.vaadin.flow.component.AbstractSinglePropertyField

getSynchronizationRegistration, setPresentationValue, setSynchronizedEvent

Methods inherited from class com.vaadin.flow.component.AbstractField

addValueChangeListener, getEmptyValue, getValue, isEmpty, setModelValue, setValue, valueEquals

Methods inherited from class com.vaadin.flow.component.Component

addListener, fireEvent, from, get, getElement, getEventBus, getId, getLocale, getParent, getTranslation, getTranslation, getUI, hasListener, isTemplateMapped, isVisible, onDetach, set, setElement, setId, setVisible

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.binder.HasDataProvider

setItems

Methods inherited from interface com.vaadin.flow.data.binder.HasItemsAndComponents

getItemPosition

Methods inherited from interface com.vaadin.flow.component.HasComponents

add

Methods inherited from interface com.vaadin.flow.data.binder.HasItems

setItems, setItems

Methods inherited from interface com.vaadin.flow.component.HasSize

getHeight, getMaxHeight, getMaxWidth, getMinHeight, getMinWidth, getWidth, setHeight, setHeightFull, setMaxHeight, setMaxWidth, setMinHeight, setMinWidth, setSizeFull, setSizeUndefined, setWidth, setWidthFull

Methods inherited from interface com.vaadin.flow.component.HasValueAndElement

isReadOnly, setReadOnly

Methods inherited from interface com.vaadin.flow.component.HasValue

addValueChangeListener, clear, getEmptyValue, getOptionalValue, getValue, isEmpty, setValue

Methods inherited from interface com.vaadin.flow.component.HasEnabled

isEnabled, setEnabled

Methods inherited from interface com.vaadin.flow.component.HasStyle

addClassName, addClassNames, getClassName, getClassNames, getStyle, hasClassName, removeClassName, removeClassNames, setClassName, setClassName

Methods inherited from interface com.vaadin.flow.component.Focusable

addFocusShortcut, blur, focus, getTabIndex, setTabIndex

Methods inherited from interface com.vaadin.flow.component.BlurNotifier

addBlurListener

Methods inherited from interface com.vaadin.flow.component.FocusNotifier

addFocusListener

Methods inherited from interface com.vaadin.flow.component.AttachNotifier

addAttachListener

Methods inherited from interface com.vaadin.flow.component.DetachNotifier

addDetachListener

Field Detail

LABEL_ATTRIBUTE

public static final String LABEL_ATTRIBUTE

See Also:

Constant Field Values

Constructor Detail

Select

public Select()

Constructs a select.

Select

public Select(T... items)

Constructs a select with the given items.

Parameters:

items - the items for the select

Method Detail

getItemRenderer

public ComponentRenderer<? extends Component,T> getItemRenderer()

Returns the item component renderer.

Returns:

the item renderer or null if none set

See Also:

setRenderer(ComponentRenderer)

setRenderer

public void setRenderer(ComponentRenderer<? extends Component,T> renderer)

Sets the item renderer for this select group. The renderer is applied to each item to create a component which represents the item option in the select's drop down.

Default is null which means that the item's Object.toString() method is used and set as the text content of the vaadin item element.

Parameters:

renderer - the item renderer, or null to clear

setTextRenderer

public void setTextRenderer(ItemLabelGenerator<T> itemLabelGenerator)

Convenience setter for creating a TextRenderer from the given function that converts the item to a string.

NOTE: even though this accepts an ItemLabelGenerator, this is not the same as setItemLabelGenerator(ItemLabelGenerator) which does a different thing.

Parameters:

itemLabelGenerator - the function that creates the text content from the item, not null

setEmptySelectionAllowed

public void setEmptySelectionAllowed(boolean emptySelectionAllowed)

Sets whether the user is allowed to select nothing. When set true a special empty item is shown to the user.

Default is false. The empty selection item can be customized with setEmptySelectionCaption(String).

Parameters:

emptySelectionAllowed - true to allow not selecting anything, false to require selection

See Also:

setEmptySelectionCaption(String)

isEmptySelectionAllowed

public boolean isEmptySelectionAllowed()

Returns whether the user is allowed to select nothing.

Returns:

true if empty selection is allowed, false otherwise

setEmptySelectionCaption

public void setEmptySelectionCaption(String emptySelectionCaption)

Sets the empty selection caption when setEmptySelectionAllowed(boolean) has been enabled. The caption is shown for the empty selection item in the drop down.

When the empty selection item is selected, the select shows the value provided by setItemLabelGenerator(ItemLabelGenerator) for the null item, or the string set with setPlaceholder(String) or an empty string if not placeholder is set.

Default is an empty string "", which will show the place holder when selected.

Parameters:

emptySelectionCaption - the empty selection caption to set, not null

See Also:

setEmptySelectionAllowed(boolean)

getEmptySelectionCaption

public String getEmptySelectionCaption()

getItemEnabledProvider

public SerializablePredicate<T> getItemEnabledProvider()

Returns the item enabled predicate.

Returns:

the item enabled predicate or null if not set

See Also:

setItemEnabledProvider(com.vaadin.flow.function.SerializablePredicate<T>)

setItemEnabledProvider

public void setItemEnabledProvider(SerializablePredicate<T> itemEnabledProvider)

Sets the item enabled predicate for this select. The predicate is applied to each item to determine whether the item should be enabled (true) or disabled (false). Disabled items are displayed as grayed out and the user cannot select them.

By default is null and all the items are enabled.

Parameters:

itemEnabledProvider - the item enable predicate or null to clear

getItemLabelGenerator

public ItemLabelGenerator<T> getItemLabelGenerator()

Gets the item label generator. It generates the text that is shown in the input part for the item when it has been selected.

Default is null.

Returns:

the item label generator, null if not set

setItemLabelGenerator

public void setItemLabelGenerator(ItemLabelGenerator<T> itemLabelGenerator)

Sets the item label generator. It generates the text that is shown in the input part for the item when it has been selected.

Default is null and the text content generated for the item with setRenderer(ComponentRenderer) is used instead.

Parameters:

itemLabelGenerator - the item label generator to set, or null to clear

getPlaceholder

public String getPlaceholder()

Gets the placeholder hint set for the user.

Returns:

the placeholder or null if none set

setPlaceholder

public void setPlaceholder(String placeholder)

Sets the placeholder hint for the user.

The placeholder will be displayed in the case that there is no item selected, or the selected item has an empty string label, or the selected item has no label and it's DOM content is empty.

Default value is null.

Overrides:

setPlaceholder in class GeneratedVaadinSelect<Select<T>,T>

Parameters:

placeholder - the placeholder to set, or null to remove

setLabel

public void setLabel(String label)

Sets the string for the label element.

NOTE: the label must be set for the required indicator to be visible.

Overrides:

setLabel in class GeneratedVaadinSelect<Select<T>,T>

Parameters:

label - string or null to clear it

getLabel

public String getLabel()

Gets the string for the label element.

Returns:

the label string, or null if not set

setAutofocus

public void setAutofocus(boolean autofocus)

Sets the select to have focus when the page loads.

Default is false.

Overrides:

setAutofocus in class GeneratedVaadinSelect<Select<T>,T>

Parameters:

autofocus - the autofocus to set

isAutofocus

public boolean isAutofocus()

Gets whether this select has been set to autofocus when the page loads.

Returns:

true if set to autofocus, false if not

setDataProvider

public void setDataProvider(DataProvider<T,?> dataProvider)

Description copied from interface: HasDataProvider

Sets the data provider for this listing. The data provider is queried for displayed items as needed.

Specified by:

setDataProvider in interface HasDataProvider<T>

Parameters:

dataProvider - the data provider, not null

getDataProvider

public DataProvider<T,?> getDataProvider()

Gets the data provider.

Returns:

the data provider, not null

onEnabledStateChanged

public void onEnabledStateChanged(boolean enabled)

Description copied from class: Component

Handle component enable state when the enabled state changes.

By default this sets or removes the 'disabled' attribute from the element. This can be overridden to have custom handling.

Overrides:

onEnabledStateChanged in class Component

Parameters:

enabled - the new enabled state of the component

setRequiredIndicatorVisible

public void setRequiredIndicatorVisible(boolean requiredIndicatorVisible)

Sets the required indicator visible or not.

If set visible, it is visually indicated in the user interface.

The method is intended to be used with Binder which does server-side validation. In case HTML element has its own (client-side) validation it should be disabled when setRequiredIndicatorVisible(true) is called and re-enabled back on setRequiredIndicatorVisible(false). It's responsibility of each component implementation to follow the contract so that the method call doesn't do anything else than show/hide the "required" indication. Usually components provide their own setRequired method which should be called in case the client-side validation is required. NOTE: The required indicator will not be visible, if the setLabel(String) property is not set for the select.

Specified by:

setRequiredIndicatorVisible in interface HasValue<AbstractField.ComponentValueChangeEvent<Select<T>,T>,T>

Specified by:

setRequiredIndicatorVisible in interface HasValueAndElement<AbstractField.ComponentValueChangeEvent<Select<T>,T>,T>

Parameters:

requiredIndicatorVisible - true to make the required indicator visible, false if not

isRequiredIndicatorVisible

public boolean isRequiredIndicatorVisible()

Checks whether the required indicator is visible. NOTE: The required indicator will not be visible, if the setLabel(String) property is not set for the select.

Specified by:

isRequiredIndicatorVisible in interface HasValue<AbstractField.ComponentValueChangeEvent<Select<T>,T>,T>

Specified by:

isRequiredIndicatorVisible in interface HasValueAndElement<AbstractField.ComponentValueChangeEvent<Select<T>,T>,T>

Returns:

true if visible, false if not

setErrorMessage

public void setErrorMessage(String errorMessage)

Sets the error message to show to the user on invalid selection.

Specified by:

setErrorMessage in interface HasValidation

Overrides:

setErrorMessage in class GeneratedVaadinSelect<Select<T>,T>

Parameters:

errorMessage - the error message or null to clear it

getErrorMessage

public String getErrorMessage()

Gets the error message to show to the user on invalid selection

Specified by:

getErrorMessage in interface HasValidation

Returns:

the error message or null if not set

setInvalid

public void setInvalid(boolean invalid)

Sets the select to show as invalid state and display error message.

Specified by:

setInvalid in interface HasValidation

Overrides:

setInvalid in class GeneratedVaadinSelect<Select<T>,T>

Parameters:

invalid - true for invalid, false for valid

isInvalid

public boolean isInvalid()

Gets whether the select is currently in invalid state.

Specified by:

isInvalid in interface HasValidation

Returns:

true for invalid, false for valid

add

public void add(Component... components)

Adds the given components as children of this component.

In case the any of the specified components has already been added to another parent, it will be removed from there and added to this one.

NOTE: If you add a component with the slot attribute set, it will be placed in the light-dom of the vaadin-select instead of the drop down, similar to addToPrefix(Component...)

Specified by:

add in interface HasComponents

Parameters:

components - the components to add

addComponents

public void addComponents(T afterItem,
                          Component... components)

Description copied from interface: HasItemsAndComponents

Adds the components after the given item.

Specified by:

addComponents in interface HasItemsAndComponents<T>

Parameters:

afterItem - item to add components after

components - components to add after item

prependComponents

public void prependComponents(T beforeItem,
                              Component... components)

Description copied from interface: HasItemsAndComponents

Adds the components before the given item.

Specified by:

prependComponents in interface HasItemsAndComponents<T>

Parameters:

beforeItem - item to add components in front of

components - components to add before item

addComponentAtIndex

public void addComponentAtIndex(int index,
                                Component component)

Adds the given component as child of this component at the specific index.

In case the specified component has already been added to another parent, it will be removed from there and added to this one.

NOTE: If you add a component with the slot attribute set, it will be placed in the light-dom of the vaadin-select instead of the drop down, similar to addToPrefix(Component...)

Specified by:

addComponentAtIndex in interface HasComponents

Parameters:

index - the index, where the component will be added. The index must be non-negative and may not exceed the children count

component - the component to add, value should not be null

addComponentAsFirst

public void addComponentAsFirst(Component component)

Adds the given component as the first child of this component.

In case the specified component has already been added to another parent, it will be removed from there and added to this one.

NOTE: If you add a component with the slot attribute set, it will be placed in the light-dom of the vaadin-select instead of the drop down, similar to addToPrefix(Component...)

Specified by:

addComponentAsFirst in interface HasComponents

Parameters:

component - the component to add, value should not be null

addToPrefix

public void addToPrefix(Component... components)

Description copied from class: GeneratedVaadinSelect

Adds the given components as children of this component at the slot 'prefix'.

Overrides:

addToPrefix in class GeneratedVaadinSelect<Select<T>,T>

Parameters:

components - The components to add.

See Also:

MDN page about slots, Spec website about slots

getChildren

public Stream<Component> getChildren()

Description copied from class: Component

Gets the child components of this component.

The default implementation finds child components by traversing each child Element tree.

If the component is injected to a PolymerTemplate using the @Id annotation the getChildren method will only return children added from the server side and will not return any children declared in the template file.

Overrides:

getChildren in class Component

Returns:

the child components of this component

See Also:

Id

remove

public void remove(Component... components)

Removes the given child components from this component.

NOTE: any component with the slot attribute will be attempted to removed from the light dom of the vaadin-select, instead of inside the options drop down.

Specified by:

remove in interface HasComponents

Overrides:

remove in class GeneratedVaadinSelect<Select<T>,T>

Parameters:

components - the components to remove

Throws:

IllegalArgumentException - if any of the components is not a child of this component

removeAll

public void removeAll()

Removes all child components that are not items. To remove all items, reset the data provider or use HasItems.setItems(Object[]).

NOTE: this will remove all non-items from the drop down and any slotted components from vaadin-select's light dom.

Specified by:

removeAll in interface HasComponents

Overrides:

removeAll in class GeneratedVaadinSelect<Select<T>,T>

See Also:

HasComponents.removeAll()

hasValidValue

protected boolean hasValidValue()

Description copied from class: AbstractSinglePropertyField

Checks whether the element property has a value that can be converted to the model type. Property changes from the element will be ignored if this method returns false. The default implementation always return true.

Overrides:

hasValidValue in class AbstractSinglePropertyField<Select<T>,T>

Returns:

true if the element property value can be converted to the model type; otherwise false

onAttach

protected void onAttach(AttachEvent attachEvent)

Description copied from class: Component

Called when the component is attached to a UI.

The default implementation does nothing.

This method is invoked before the AttachEvent is fired for the component.

Overrides:

onAttach in class Component

Parameters:

attachEvent - the attach event