Package eu.webtoolkit.jwt

Class EventSignal

java.lang.Object
eu.webtoolkit.jwt.AbstractSignal
eu.webtoolkit.jwt.AbstractEventSignal
eu.webtoolkit.jwt.EventSignal
public class EventSignal extends AbstractEventSignal
An signal which relays a browser event. This event signal does not pass any event details.

  • Method Details

    • addListener

      public AbstractSignal.Connection addListener(WObject listenerOwner, Signal.Listener listener)
      Description copied from class: AbstractSignal
      Adds a listener for this signal.

      Each listener will be notified when the signal is triggered.

      An owner object may be passed when the listener is implemented using an (anonymous) inner class. In that case the owner object should be the enclosing object of the listener object, and this is used to bind the lifetime of the listener. To avoid the owner object from not being garbage collected when it is no longer used, only the owner object will add a reference to the listener, while the signal will use a weak reference.

      This avoids the most common reason for memory leaks in Java implementations of the Observer pattern: the owner object will not get garbage collected because of the (anonymous) listener object having a reference to it, even if the receiver object is no longer referenced from anywhere. When the owner object is not null, the listener is stored using a strong reference in the owner object, and using a weak reference in the signal.

      Specified by:
      addListener in class AbstractSignal
      Parameters:
      listenerOwner - if not null, the enclosing object for a listener implemented using an inner class
      listener - the listener
      Returns:
      a connection object that may be used to control the connection

    • getListenerCount

      protected int getListenerCount()
      Description copied from class: AbstractSignal
      Returns the number of connected listeners.
      Overrides:
      getListenerCount in class AbstractEventSignal
      Returns:
      the number of connected listeners.

    • removeListener

      public void removeListener(Signal.Listener listener)
      Description copied from class: AbstractSignal
      Removes a listener.

      Specified by:
      removeListener in class AbstractSignal
      Parameters:
      listener - a listener that was previously added.

    • trigger

      public void trigger()

    • addListener

      public void addListener(JSlot slot)
      Description copied from class: AbstractEventSignal
      Adds a JavaScript event listener.
      Overrides:
      addListener in class AbstractEventSignal
      Parameters:
      slot - the JavaScript event listener

    • addListener

      public void addListener(WObject receiver, AbstractEventSignal.LearningListener listener)
      Description copied from class: AbstractEventSignal
      Adds a learning listener to this signal.

      An owner object may be passed when the listener is implemented using an anonymous inner class. In that case the owner object should be the enclosing object of the listener object, and this is used to bind the lifetime of the listener: when the owner object is garbage collected, the listener will be freed as well. This avoids the most common reason for memory leaks in Java implementations of the Observer pattern: the owner object will not get garbage collected because of the (anonymous) listener object having a reference to it, even if the receiver object is no longer referenced from anywhere. When the owner object is not null, the listener is stored using a strong reference in the owner object, and using a weak reference in the signal. Note: The receiver is currently not yet used.

      Overrides:
      addListener in class AbstractEventSignal
      Parameters:
      receiver - if not null, the enclosing object for an anonymous listener
      listener - the listener

    • getArgumentCount

      protected int getArgumentCount()
      Description copied from class: AbstractSignal
      Returns the number of parameters (excluding an 'event').
      Specified by:
      getArgumentCount in class AbstractSignal