Module javafx.base
Package javafx.beans

Interface Observable

    • Method Detail

      • addListener

        void addListener​(InvalidationListener listener)
        Adds an InvalidationListener which will be notified whenever the Observable becomes invalid. If the same listener is added more than once, then it will be notified more than once. That is, no check is made to ensure uniqueness.

        Note that the same actual InvalidationListener instance may be safely registered for different Observables.

        The Observable stores a strong reference to the listener which will prevent the listener from being garbage collected and may result in a memory leak. It is recommended to either unregister a listener by calling removeListener after use or to use an instance of WeakInvalidationListener avoid this situation.

        Parameters:
        listener - The listener to register
        Throws:
        NullPointerException - if the listener is null
        See Also:
        removeListener(InvalidationListener)
      • removeListener

        void removeListener​(InvalidationListener listener)
        Removes the given listener from the list of listeners, that are notified whenever the value of the Observable becomes invalid.

        If the given listener has not been previously registered (i.e. it was never added) then this method call is a no-op. If it had been previously added then it will be removed. If it had been added more than once, then only the first occurrence will be removed.

        Parameters:
        listener - The listener to remove
        Throws:
        NullPointerException - if the listener is null
        See Also:
        addListener(InvalidationListener)