Method Details

• addEventData

  DomListenerRegistration addEventData(String eventData)

  Add a JavaScript expression for extracting event data. When an event is fired in the browser, the expression is evaluated and its value is sent back to the server. The expression is evaluated in a context where element refers to this element and event refers to the fired event. If multiple expressions are defined for the same event, their order of execution is undefined.

  The result of the evaluation is available in DomEvent.getEventData() with the expression as the key in the JSON object. An expression might be e.g.

  • element.value the get the value of an input element for a change event.
  • event.button === 0 to get true for click events triggered by the primary mouse button.

  Parameters:

  eventData - definition for data that should be passed back to the server together with the event, not null

  Returns:

  this registration, for chaining

  See Also:

  • for mapping an element
  • to map the event.target to an element

• setFilter

  DomListenerRegistration setFilter(String filter)

  Sets a JavaScript expression that is used for filtering events to this listener. When an event is fired in the browser, the expression is evaluated and an event is sent to the server only if the expression value is true-ish according to JavaScript type coercion rules. The expression is evaluated in a context where element refers to this element and event refers to the fired event.

  An expression might be e.g. event.button === 0 to only forward events triggered by the primary mouse button.

  Any previous filter for this registration is discarded.

  Parameters:

  filter - the JavaScript filter expression, or null to clear the filter

  Returns:

  this registration, for chaining

• getFilter

  String getFilter()

  Gets the currently set filter expression.

  Returns:

  the current filter expression, or null if no filter is in use

  See Also:

  • setFilter(String)

• setDisabledUpdateMode

  DomListenerRegistration setDisabledUpdateMode(DisabledUpdateMode disabledUpdateMode)

  Configure whether this listener will be called even in cases when the element is disabled.

  When used in combination with synchronizeProperty(String), the most permissive update mode for the same property will be effective. This means that there might be unexpected property updates for a disabled component if multiple parties independently configure different aspects for the same component. This is based on the assumption that if a property is explicitly safe to update for disabled components in one context, then the nature of that property is probably such that it's also safe to update in other contexts.

  Parameters:

  disabledUpdateMode - controls RPC communication from the client side to the server side when the element is disabled, not null

  Returns:

  this registration, for chaining

• debounce

  DomListenerRegistration debounce(int timeout, DebouncePhase firstPhase, DebouncePhase... rest)

  Configures the debouncing phases for which this listener should be triggered. Debouncing is disabled and the set phases are ignored if timeout is set to 0 (the default).

  This methods overrides the settings previously set through debounce(int), throttle(int) or debounce(int, DebouncePhase, DebouncePhase...).

  The tested and supported combinations of phases are:

  DebouncePhase.TRAILING

  The server side is notified once after the event hasn't been triggered within the timeout. For example only the last keydown event is fired if a person continuously types without pauses longer than the timeout. This is the most commonly used mode. There is debounce(int) shorthand for this mode.

  DebouncePhase.LEADING

  In this case you only get notified of this event once right away on the server side. Other events of the same type will be ignored until the timeout has passed.

  DebouncePhase.LEADING + DebouncePhase.TRAILING

  This works like with the basic DebouncePhase.TRAILING, but in addition the first event of the burst gets reported rightaway. This is good if your want normal debouncing, but you are also interested to know if the user input has started.

  DebouncePhase.TIMEOUT

  In this case the listener is triggered only after the given timeout. If there are multiple events during that period, only the last one is reported.

  DebouncePhase.LEADING + DebouncePhase.TIMEOUT

  In this case the listener is triggered when an event burst starts, but afterwards only after the given timeout has passed. There is throttle(int) shorthand for this mode.

  In case another event in the UI triggers a "server roundtrip" from the client-side, events possibly queued by the debouncer are fired before that. Thus, events may occur before than expected. Also in the otherway around, due to the client-server nature of the web apps, events may arrive bit late. Do not expect debouncing to be perfectly deterministic!

  Also note that due to the client-side implementation, de-bounce settings are global for keys formed of "element-to-event-type-to-timeout". Behavior is unspecified if you configure multiple debouncing rules for the same event on the same element.

  Parameters:

  timeout - the debounce timeout in milliseconds, or 0 to disable debouncing

  firstPhase - the first phase to use. If you are interested about the first event in the burst, you should give DebouncePhase.TRAILING as a parameter here. Otherwise either DebouncePhase.TRAILING or DebouncePhase.INTERMEDIATE.

  rest - any remaining phases to use. In practice, only either DebouncePhase.TRAILING and DebouncePhase.INTERMEDIATE should be given here, if DebouncePhase.LEADING is given as a firstPhase.

  Returns:

  this registration, for chaining

  See Also:

  • DebouncePhase

• debounce

  default DomListenerRegistration debounce(int timeout)

  Configures this listener to be notified only when at least timeout milliseconds has passed since the last time the event was triggered. This is useful for cases such as text input where it's only relevant to know the result once the user stops typing.

  This is a shorthand for debounce(int, DebouncePhase, DebouncePhase...) with only DebouncePhase.TRAILING specified. See debounce(int, DebouncePhase, DebouncePhase...) for complete documentation!

  Parameters:

  timeout - the debounce timeout in milliseconds, or 0 to disable debouncing

  Returns:

  this registration, for chaining

• throttle

  default DomListenerRegistration throttle(int period)

  Configures this listener to not be notified more often than period milliseconds.

  Throttling is disabled if the period is set to 0.

  This is a shorthand for debounce(int, DebouncePhase, DebouncePhase...) with DebouncePhase.LEADING and DebouncePhase.INTERMEDIATE specified. See debounce(int, DebouncePhase, DebouncePhase...) for complete documentation!

  Parameters:

  period - the minimum period between listener invocations, or 0 to disable throttling

  Returns:

  this registration, for chaining

• getDebounceTimeout

  default int getDebounceTimeout()

  Gets the debounce timeout that is configured by debounce or throttle.

  Returns:

  timeout in milliseconds, or 0 if debouncing is disabled

  See Also:

  • debounce(int, DebouncePhase, DebouncePhase...)
  • debounce(int)
  • throttle(int)

• getDebouncePhases

  default Set<DebouncePhase> getDebouncePhases()

  Gets the debouncing phases for which this listener should be triggered.

  Returns:

  debounce phases

  See Also:

  • debounce(int, DebouncePhase, DebouncePhase...)
  • debounce(int)
  • throttle(int)

• getEventType

  default String getEventType()

  Gets the event type that the listener is registered for.

  Returns:

  DOM event type of the listener

• onUnregister

  default DomListenerRegistration onUnregister(SerializableRunnable unregisterHandler)

  Adds a handler that will be run when this registration is removed.

  Parameters:

  unregisterHandler - the handler to run when the registration is removed, not null

  Returns:

  this registration, for chaining

  Since:

  1.3

• synchronizeProperty

  default DomListenerRegistration synchronizeProperty(String propertyName)

  Marks that the DOM event of this registration should trigger synchronization for the given property.

  Parameters:

  propertyName - the name of the property to synchronize, not null or ""

  Returns:

  this registration, for chaining

• mapEventTargetElement

  default DomListenerRegistration mapEventTargetElement()

  Marks that the DOM event should map the event.target to the closest corresponding Element on the server side, to be returned by DomEvent.getEventTarget().

  Returns:

  this registration, for chaining

  Since:

  9.0

• addEventDataElement

  default DomListenerRegistration addEventDataElement(String eventData)

  Add a JavaScript expression for extracting an element as event data. When an event is fired in the browser, the expression is evaluated and if it returns an element from DOM, the server side element or closest parent element is sent to server side. The expression is evaluated in a context where element refers to this element and event refers to the fired event. If multiple expressions are defined for the same event, their order of execution is undefined.

  The result of the evaluation is available in DomEvent.getEventDataElement(String) with the expression as the key in the JSON object.

  In case you want to get the event.target element to the server side, use the mapEventTargetElement() method to get it mapped and the DomEvent.getEventTarget() to fetch the element.

  Parameters:

  eventData - definition for element that should be passed back to the server together with the event, not null

  Returns:

  this registration, for chaining

  Since:

  9.0

  See Also:

  • to map the event.target to an element

• stopPropagation

  default DomListenerRegistration stopPropagation()

  Stops propagation of the event to upper level DOM elements.

  Returns:

  the DomListenerRegistration for further configuration

  See Also:

  • MDN docs for related JS DOM API

• preventDefault

  default DomListenerRegistration preventDefault()

  Tries to prevent the default behavior of the event in the browser, such as shortcut action on key press or context menu on "right click". This might not be possible for some events.

  Returns:

  the DomListenerRegistration for further configuration

  See Also:

  • MDN docs for related JS DOM API

• allowInert

  DomListenerRegistration allowInert()

  Configures the event listener to bypass the server side security checks for modality. Handle with care! Can be ok when transferring data from "non-ui" component events through the Element API, like e.g. geolocation events.

  Returns:

  the DomListenerRegistration for further configuration