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com.vaadin.client.

Class EventHelper

  • public class EventHelper
extends Object

    Helper class for attaching/detaching handlers for Vaadin client side components, based on identifiers in UIDL. Helpers expect Paintables to be both listeners and sources for events. This helper cannot be used for more complex widgets.

    Possible current registration is given as parameter. The returned registration (possibly the same as given, should be store for next update.

    Pseudocode what helpers do: 

     if paintable has event listener in UIDL
      if registration is null
              register paintable as as handler for event
      return the registration
 else
      if registration is not null
              remove the handler from paintable
      return null

    • Constructor Summary

      Constructors
      Constructor Description
      EventHelper()  

    • Method Summary

      All Methods
      Modifier and Type Method Description
      static <T extends ComponentConnector & com.google.gwt.event.dom.client.BlurHandler>
      com.google.gwt.event.shared.HandlerRegistration      		 updateBlurHandler​(T connector, com.google.gwt.event.shared.HandlerRegistration handlerRegistration)

      Adds or removes a blur handler depending on if the connector has blur listeners on the server side or not.
      static <T extends ComponentConnector & com.google.gwt.event.dom.client.BlurHandler>
      com.google.gwt.event.shared.HandlerRegistration      		 updateBlurHandler​(T connector, com.google.gwt.event.shared.HandlerRegistration handlerRegistration, com.google.gwt.user.client.ui.Widget widget)

      Adds or removes a blur handler depending on if the connector has blur listeners on the server side or not.
      static <T extends ComponentConnector & com.google.gwt.event.dom.client.FocusHandler>
      com.google.gwt.event.shared.HandlerRegistration      		 updateFocusHandler​(T connector, com.google.gwt.event.shared.HandlerRegistration handlerRegistration)

      Adds or removes a focus handler depending on if the connector has focus listeners on the server side or not.
      static <T extends ComponentConnector & com.google.gwt.event.dom.client.FocusHandler>
      com.google.gwt.event.shared.HandlerRegistration      		 updateFocusHandler​(T connector, com.google.gwt.event.shared.HandlerRegistration handlerRegistration, com.google.gwt.user.client.ui.Widget widget)

      Adds or removes a focus handler depending on if the connector has focus listeners on the server side or not.
      static <H extends com.google.gwt.event.shared.EventHandler>
      com.google.gwt.event.shared.HandlerRegistration      		 updateHandler​(ComponentConnector connector, H handler, String eventIdentifier, com.google.gwt.event.shared.HandlerRegistration handlerRegistration, com.google.gwt.event.dom.client.DomEvent.Type<H> type, com.google.gwt.user.client.ui.Widget widget)  
      static <H extends com.google.gwt.event.shared.EventHandler,​W extends com.google.gwt.user.client.ui.Widget>
      com.google.gwt.event.shared.HandlerRegistration      		 updateHandler​(ComponentConnector connector, String eventIdentifier, com.google.gwt.event.shared.HandlerRegistration handlerRegistration, Supplier<com.google.gwt.event.shared.HandlerRegistration> handlerProvider)

      Updates handler registered using handlerProvider: removes it if connector doesn't have anymore eventIdentifier using provided handlerRegistration and adds it via provided handlerProvider if connector has event listener with eventIdentifier.

    • Constructor Detail

      • EventHelper

        public EventHelper()

    • Method Detail

      • updateFocusHandler

        public static <T extends ComponentConnector & com.google.gwt.event.dom.client.FocusHandler> com.google.gwt.event.shared.HandlerRegistration updateFocusHandler​(T connector,
                                                                                                                                                               com.google.gwt.event.shared.HandlerRegistration handlerRegistration)

        Adds or removes a focus handler depending on if the connector has focus listeners on the server side or not.

        Parameters:

        connector - The connector to update. Must implement focusHandler.

        handlerRegistration - The old registration reference or null if no handler has been registered previously

        Returns:

        a new registration handler that can be used to unregister the handler later

      • updateFocusHandler

        public static <T extends ComponentConnector & com.google.gwt.event.dom.client.FocusHandler> com.google.gwt.event.shared.HandlerRegistration updateFocusHandler​(T connector,
                                                                                                                                                               com.google.gwt.event.shared.HandlerRegistration handlerRegistration,
                                                                                                                                                               com.google.gwt.user.client.ui.Widget widget)

        Adds or removes a focus handler depending on if the connector has focus listeners on the server side or not.

        Parameters:

        connector - The connector to update. Must implement focusHandler.

        handlerRegistration - The old registration reference or null if no handler has been registered previously

        widget - The widget which emits focus events

        Returns:

        a new registration handler that can be used to unregister the handler later

      • updateBlurHandler

        public static <T extends ComponentConnector & com.google.gwt.event.dom.client.BlurHandler> com.google.gwt.event.shared.HandlerRegistration updateBlurHandler​(T connector,
                                                                                                                                                             com.google.gwt.event.shared.HandlerRegistration handlerRegistration)

        Adds or removes a blur handler depending on if the connector has blur listeners on the server side or not.

        Parameters:

        connector - The connector to update. Must implement BlurHandler.

        handlerRegistration - The old registration reference or null if no handler has been registered previously

        Returns:

        a new registration handler that can be used to unregister the handler later

      • updateBlurHandler

        public static <T extends ComponentConnector & com.google.gwt.event.dom.client.BlurHandler> com.google.gwt.event.shared.HandlerRegistration updateBlurHandler​(T connector,
                                                                                                                                                             com.google.gwt.event.shared.HandlerRegistration handlerRegistration,
                                                                                                                                                             com.google.gwt.user.client.ui.Widget widget)

        Adds or removes a blur handler depending on if the connector has blur listeners on the server side or not.

        Parameters:

        connector - The connector to update. Must implement BlurHandler.

        handlerRegistration - The old registration reference or null if no handler has been registered previously

        widget - The widget which emits blur events

        Returns:

        a new registration handler that can be used to unregister the handler later

      • updateHandler

        public static <H extends com.google.gwt.event.shared.EventHandler> com.google.gwt.event.shared.HandlerRegistration updateHandler​(ComponentConnector connector,
                                                                                                                                 H handler,
                                                                                                                                 String eventIdentifier,
                                                                                                                                 com.google.gwt.event.shared.HandlerRegistration handlerRegistration,
                                                                                                                                 com.google.gwt.event.dom.client.DomEvent.Type<H> type,
                                                                                                                                 com.google.gwt.user.client.ui.Widget widget)

      • updateHandler

        public static <H extends com.google.gwt.event.shared.EventHandler,​W extends com.google.gwt.user.client.ui.Widget> com.google.gwt.event.shared.HandlerRegistration updateHandler​(ComponentConnector connector,
                                                                                                                                                                                      String eventIdentifier,
                                                                                                                                                                                      com.google.gwt.event.shared.HandlerRegistration handlerRegistration,
                                                                                                                                                                                      Supplier<com.google.gwt.event.shared.HandlerRegistration> handlerProvider)

        Updates handler registered using handlerProvider: removes it if connector doesn't have anymore eventIdentifier using provided handlerRegistration and adds it via provided handlerProvider if connector has event listener with eventIdentifier.

        Parameters:

        connector - connector to check event listener presence

        eventIdentifier - event identifier whose presence in the connector is checked

        handlerRegistration - resulting handler registration to remove added handler in case of absence event listener

        handlerProvider - the strategy to register handler

        Returns:

        handlerRegistration which should be used to remove registered handler via handlerProvider