com.vaadin.flow.component

Class ComponentUtil

java.lang.Object

com.vaadin.flow.component.ComponentUtil

public class ComponentUtil
extends Object

Utility methods for Component.

Since:

1.0

Author:

Vaadin Ltd

Method Summary

Modifier and Type	Method and Description
static <T extends ComponentEvent<?>> Registration	addListener(Component component, Class<T> eventType, ComponentEventListener<T> listener) Adds a listener for an event of the given type to the component.
static <T extends ComponentEvent<?>> Registration	addListener(Component component, Class<T> eventType, ComponentEventListener<T> listener, Consumer<DomListenerRegistration> domListenerConsumer) Adds a listener for an event of the given type to the component, and customizes the corresponding DOM event listener with the given consumer.
static <T extends Component> T	componentFromElement(Element element, Class<T> componentType, boolean mapComponent) Creates a new component instance using the given element, maps the component to the element and optionally maps the element to the component (if mapComponent is true).
static void	findComponents(Element element, Consumer<Component> componentConsumer) Finds the first component instance in each Element subtree by traversing the Element tree starting from the given element.
static Optional<Component>	findParentComponent(Element element) Finds the first component by traversing upwards in the element hierarchy, starting from the given element.
static <T extends Component> void	fireEvent(T component, ComponentEvent<? extends T> componentEvent) Dispatches the event to all listeners registered for the event type.
static <T> T	getData(Component component, Class<T> type) Gets a data instance with the given type, or null if there is no such instance.
static Object	getData(Component component, String key) Gets a data instance with the given key, or null if no data has been set for that key.
static ComponentMetaData.DependencyInfo	getDependencies(VaadinService service, Class<? extends Component> componentClass) Gets the dependencies for the given class, defined using annotations ( HtmlImport, JavaScript, StyleSheet and Uses).
static Component	getInnermostComponent(Composite<?> composite) Returns the innermost component from a Composite chain, i.e.
static Component	getInnermostComponent(Element element) Gets the innermost mapped component for the element.
static Component	getParentUsingComposite(Composite<?> composite, Component component) Gets the parent of the given component, which is inside the given composite.
static Collection<ComponentMetaData.SynchronizedPropertyInfo>	getSynchronizedProperties(Class<? extends Component> componentClass) Gets the synchronized property infos of the properties that are defined declaratively for the given class with their RPC update mode.
static Stream<String>	getSynchronizedPropertyEvents(Class<? extends Component> componentClass) Gets the name of the synchronized property event defined declaratively for the given class.
static boolean	isCompositeContent(Composite<?> composite, Component component) Checks if the given component is inside a Composite chain, i.e.
static void	onComponentAttach(Component component, boolean initialAttach) Handles triggering the onAttach method and firing the AttachEvent for the given component when it has been attached to a UI.
static void	onComponentDetach(Component component) Handles triggering the onDetach method and firing the DetachEvent for the given component right before it is detached from a UI.
static <T> void	setData(Component component, Class<T> type, T value) Stores an instance of a specific type for the given component.
static void	setData(Component component, String key, Object value) Stores a arbitrary value for the given component.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

findComponents

public static void findComponents(Element element,
                                  Consumer<Component> componentConsumer)

Finds the first component instance in each Element subtree by traversing the Element tree starting from the given element.

Parameters:

element - the element to start scanning from

componentConsumer - a consumer which is called for each found component

getParentUsingComposite

public static Component getParentUsingComposite(Composite<?> composite,
                                                Component component)

Gets the parent of the given component, which is inside the given composite.

This method is meant for internal use only.

Parameters:

composite - the composite containing the component

component - the component to get the parent for, must be inside the composite or a nested composite

Returns:

the parent of the component, never null

getInnermostComponent

public static Component getInnermostComponent(Composite<?> composite)

Returns the innermost component from a Composite chain, i.e. the first content which is not a Composite.

Parameters:

composite - a composite in the chain

Returns:

the innermost component

isCompositeContent

public static boolean isCompositeContent(Composite<?> composite,
                                         Component component)

Checks if the given component is inside a Composite chain, i.e. it is a composite in the chain or the content of the innermost Composite.

Parameters:

composite - the first composite

component - the component to look for

Returns:

true if the component is inside the composite chain, false otherwise

findParentComponent

public static Optional<Component> findParentComponent(Element element)

Finds the first component by traversing upwards in the element hierarchy, starting from the given element.

Parameters:

element - the element from which to begin the search

Returns:

optional of the component, empty if no component is found

getInnermostComponent

public static Component getInnermostComponent(Element element)

Gets the innermost mapped component for the element.

This returns Element.getComponent() if something else than a Composite is mapped to the element. If a Composite is mapped to the element, finds the innermost content of the Composite chain.

Parameters:

element - the element which is mapped to a component

Returns:

the innermost component mapped to the element

onComponentAttach

public static void onComponentAttach(Component component,
                                     boolean initialAttach)

Handles triggering the onAttach method and firing the AttachEvent for the given component when it has been attached to a UI.

Parameters:

component - the component attached to a UI

initialAttach - indicates if this is the first time the component (element) has been attached

onComponentDetach

public static void onComponentDetach(Component component)

Handles triggering the onDetach method and firing the DetachEvent for the given component right before it is detached from a UI.

Parameters:

component - the component detached from a UI

addListener

public static <T extends ComponentEvent<?>> Registration addListener(Component component,
                                                                     Class<T> eventType,
                                                                     ComponentEventListener<T> listener)

Adds a listener for an event of the given type to the component.

Type Parameters:

T - the component event type

Parameters:

component - the component to add the listener

eventType - the component event type, not null

listener - the listener to add, not null

Returns:

a handle that can be used for removing the listener

addListener

public static <T extends ComponentEvent<?>> Registration addListener(Component component,
                                                                     Class<T> eventType,
                                                                     ComponentEventListener<T> listener,
                                                                     Consumer<DomListenerRegistration> domListenerConsumer)

Adds a listener for an event of the given type to the component, and customizes the corresponding DOM event listener with the given consumer. This allows overriding eg. the debounce settings defined in the DomEvent annotation.

Note that customizing the DOM event listener works only for event types which are annotated with DomEvent. Use addListener(Component, Class, ComponentEventListener) for other listeners, or if you don't need to customize the DOM listener.

Type Parameters:

T - the event type

Parameters:

component - the component to add the listener

eventType - the event type for which to call the listener, must be annotated with DomEvent

listener - the listener to call when the event occurs, not null

domListenerConsumer - a consumer to customize the behavior of the DOM event listener, not null

Returns:

a handle that can be used for removing the listener

Throws:

IllegalArgumentException - if the event type is not annotated with DomEvent

fireEvent

public static <T extends Component> void fireEvent(T component,
                                                   ComponentEvent<? extends T> componentEvent)

Dispatches the event to all listeners registered for the event type.

Type Parameters:

T - the type of the component

Parameters:

component - the component for which to fire events

componentEvent - the event to fire

See Also:

Component.fireEvent(ComponentEvent)

componentFromElement

public static <T extends Component> T componentFromElement(Element element,
                                                           Class<T> componentType,
                                                           boolean mapComponent)

Creates a new component instance using the given element, maps the component to the element and optionally maps the element to the component (if mapComponent is true).

This is a helper method for Element#as and Component#from.

Type Parameters:

T - the component type

Parameters:

element - the element

componentType - the component type

mapComponent - true to also map the element to the component, false to only map the component to the element

Returns:

a new component instance of the given type

See Also:

Component.from(Element, Class), Element.as(Class)

getSynchronizedProperties

public static Collection<ComponentMetaData.SynchronizedPropertyInfo> getSynchronizedProperties(Class<? extends Component> componentClass)

Gets the synchronized property infos of the properties that are defined declaratively for the given class with their RPC update mode.

Parameters:

componentClass - the component class to check

Returns:

the synchronized property infos of the properties defined declaratively for the class

getSynchronizedPropertyEvents

public static Stream<String> getSynchronizedPropertyEvents(Class<? extends Component> componentClass)

Gets the name of the synchronized property event defined declaratively for the given class.

Parameters:

componentClass - the component class to check

Returns:

the synchronized property events defined declaratively for the class

getDependencies

public static ComponentMetaData.DependencyInfo getDependencies(VaadinService service,
                                                               Class<? extends Component> componentClass)

Gets the dependencies for the given class, defined using annotations ( HtmlImport, JavaScript, StyleSheet and Uses).

Parameters:

service - the service to use for resolving dependencies

componentClass - the component class to check

Returns:

the dependencies for the given class

setData

public static void setData(Component component,
                           String key,
                           Object value)

Stores a arbitrary value for the given component.

Parameters:

component - the component for which to set the data

key - the key with which the instance can be retrieved, not null

value - the data to set, or null to remove data previously set with the same key

See Also:

setData(Component, Class, Object), getData(Component, String)

setData

public static <T> void setData(Component component,
                               Class<T> type,
                               T value)

Stores an instance of a specific type for the given component.

Type Parameters:

T - the data instance type

Parameters:

component - the component for which to set the data

type - the type of the data to set, not null

value - the data instance to set, or null to remove data previously set with the same type

See Also:

setData(Component, String, Object), getData(Component, Class)

getData

public static Object getData(Component component,
                             String key)

Gets a data instance with the given key, or null if no data has been set for that key.

Parameters:

component - the component from which to get the data

key - the data key

Returns:

the data instance, or null if no instance has been set using the given key

See Also:

setData(Component, String, Object)

getData

public static <T> T getData(Component component,
                            Class<T> type)

Gets a data instance with the given type, or null if there is no such instance.

Type Parameters:

T - the data instance type

Parameters:

component - the component from which to get the data

type - the data type

Returns:

the data instance, or null if no instance has been set using the given type

See Also:

setData(Component, Class, Object)