Package org.djutils.event

Class EventProducer

java.lang.Object
org.djutils.event.EventProducer
All Implemented Interfaces:
Serializable, EventProducerInterface
Direct Known Subclasses:
EventProducingCollection, EventProducingIterator, EventProducingList, EventProducingMap, EventProducingSet
public abstract class EventProducer
extends Object
implements EventProducerInterface, Serializable
The EventProducer forms the reference implementation of the EventProducerInterface. Objects extending this class are provided all the functionalities for registration and event firing. The storage of the listeners is done in a Map with the EventType as the key, and a List of References (weak or strong) to the Listeners. The class uses a helper class EventProducerImpl to do the real work, and avoid code duplication.

Copyright (c) 2002-2020 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See for project information https://djutils.org. The DJUTILS project is distributed under a three-clause BSD-style license, which can be found at https://djutils.org/docs/license.html. This class was originally part of the DSOL project, see https://simulation.tudelft.nl/dsol/manual.

Author:
Peter Jacobs , Alexander Verbraeck
See Also:
Serialized Form

  • Field Details

  • Constructor Details

    • EventProducer

      public EventProducer()
      Constructs a new EventProducer and checks for duplicate values in event types.

  • Method Details

    • getSourceId

      public abstract Serializable getSourceId()
      Provide the sourceId that will be transmitted with the fired Event.
      Specified by:
      getSourceId in interface EventProducerInterface
      Returns:
      Serializable; the sourceId that will be transmitted with the fired Event

    • addListener

      public final boolean addListener​(EventListenerInterface listener, EventType eventType)
      Add a listener as strong reference to the BEGINNING of a queue of listeners.
      Specified by:
      addListener in interface EventProducerInterface
      Parameters:
      listener - EventListenerInterface; the listener which is interested at events of eventType
      eventType - EventType; the events of interest
      Returns:
      the success of adding the listener. If a listener was already added false is returned

    • addListener

      public final boolean addListener​(EventListenerInterface listener, EventType eventType, ReferenceType referenceType)
      Add a listener to the BEGINNING of a queue of listeners.
      Specified by:
      addListener in interface EventProducerInterface
      Parameters:
      listener - EventListenerInterface; the listener which is interested at events of eventType
      eventType - EventType; the events of interest
      referenceType - ReferenceType; whether the listener is added as a strong or as a weak reference
      Returns:
      the success of adding the listener. If a listener was already added false is returned
      See Also:
      WeakReference

    • addListener

      public final boolean addListener​(EventListenerInterface listener, EventType eventType, int position)
      Add a listener as strong reference to the specified position of a queue of listeners.
      Specified by:
      addListener in interface EventProducerInterface
      Parameters:
      listener - EventListenerInterface; the listener which is interested at events of eventType
      eventType - EventType; the events of interest
      position - int; the position of the listener in the queue
      Returns:
      the success of adding the listener. If a listener was already added, or an illegal position is provided false is returned

    • addListener

      public final boolean addListener​(EventListenerInterface listener, EventType eventType, int position, ReferenceType referenceType)
      Add a listener to the specified position of a queue of listeners.
      Specified by:
      addListener in interface EventProducerInterface
      Parameters:
      listener - EventListenerInterface; which is interested at certain events
      eventType - EventType; the events of interest
      position - int; the position of the listener in the queue
      referenceType - ReferenceType; whether the listener is added as a strong or as a weak reference
      Returns:
      the success of adding the listener. If a listener was already added or an illegal position is provided false is returned
      See Also:
      WeakReference

    • fireEvent

      protected EventInterface fireEvent​(EventInterface event)
      Transmit an event to all interested listeners.
      Parameters:
      event - EventInterface; the event
      Returns:
      EventInterface; the event (for method chaining)

    • fireEvent

      protected Serializable fireEvent​(EventType eventType, Serializable value)
      Transmit an event with a serializable object as payload to all interested listeners.
      Parameters:
      eventType - EventType; the eventType of the event
      value - Serializable; the object sent with the event
      Returns:
      Serializable; the payload

    • fireEvent

      protected void fireEvent​(EventType eventType)
      Transmit an event with no payload object to all interested listeners.
      Parameters:
      eventType - EventType; the eventType of the event

    • fireTimedEvent

      protected <C extends Comparable<C> & Serializable> Serializable fireTimedEvent​(EventType eventType, Serializable value, C time)
      Transmit a time-stamped event with a Serializable object (payload) to all interested listeners.
      Type Parameters:
      C - the comparable type to indicate the time when the event is fired
      Parameters:
      eventType - EventType; the eventType of the event.
      value - Serializable; the payload sent with the event
      time - C; a time stamp for the event
      Returns:
      Serializable; the payload

    • fireEvent

      protected byte fireEvent​(EventType eventType, byte value)
      Transmit an event with a one byte payload to all interested listeners.
      Parameters:
      eventType - EventType; the eventType of the event
      value - byte; the payload
      Returns:
      byte; the payload

    • fireTimedEvent

      protected <C extends Comparable<C> & Serializable> byte fireTimedEvent​(EventType eventType, byte value, C time)
      Transmit a time-stamped event with a one byte payload to all interested listeners.
      Type Parameters:
      C - the comparable type to indicate the time when the event is fired
      Parameters:
      eventType - EventType; the eventType of the event
      value - byte; the payload
      time - C; a time stamp for the event
      Returns:
      byte; the payload

    • fireEvent

      protected boolean fireEvent​(EventType eventType, boolean value)
      Transmit an event with a boolean payload to all interested listeners.
      Parameters:
      eventType - EventType; the eventType of the event
      value - boolean; the payload
      Returns:
      boolean; the payload

    • fireTimedEvent

      protected <C extends Comparable<C> & Serializable> boolean fireTimedEvent​(EventType eventType, boolean value, C time)
      Transmit a time-stamped event with a boolean payload to all interested listeners.
      Type Parameters:
      C - the comparable type to indicate the time when the event is fired
      Parameters:
      eventType - EventType; the eventType of the event
      value - boolean; the payload
      time - C; a time stamp for the event
      Returns:
      boolean; the payload

    • fireEvent

      protected double fireEvent​(EventType eventType, double value)
      Transmit an event with a double value payload to all interested listeners.
      Parameters:
      eventType - EventType; the eventType of the event
      value - double; the payload
      Returns:
      double; the payload

    • fireTimedEvent

      protected <C extends Comparable<C> & Serializable> double fireTimedEvent​(EventType eventType, double value, C time)
      Transmit a time-stamped event with a double value payload to interested listeners.
      Type Parameters:
      C - the comparable type to indicate the time when the event is fired
      Parameters:
      eventType - EventType; the eventType of the event
      value - double; the payload
      time - C; a time stamp for the event
      Returns:
      double; the payload

    • fireEvent

      protected int fireEvent​(EventType eventType, int value)
      Transmit an event with an integer payload to all interested listeners.
      Parameters:
      eventType - EventType; the eventType of the event
      value - int; the payload
      Returns:
      int; the payload

    • fireTimedEvent

      protected <C extends Comparable<C> & Serializable> int fireTimedEvent​(EventType eventType, int value, C time)
      Transmit a time-stamped event with an integer payload to all interested listeners.
      Type Parameters:
      C - the comparable type to indicate the time when the event is fired
      Parameters:
      eventType - EventType; the eventType of the event
      value - int; the payload
      time - C; a time stamp for the event
      Returns:
      int; the payload

    • fireEvent

      protected long fireEvent​(EventType eventType, long value)
      Transmit an event with a long payload to all interested listeners.
      Parameters:
      eventType - EventType; the eventType of the event
      value - long; the payload
      Returns:
      long; the payload

    • fireTimedEvent

      protected <C extends Comparable<C> & Serializable> long fireTimedEvent​(EventType eventType, long value, C time)
      Transmit a time-stamped event with a long payload to all interested listeners.
      Type Parameters:
      C - the comparable type to indicate the time when the event is fired
      Parameters:
      eventType - EventType; the eventType of the event
      value - long; the payload
      time - C; a time stamp for the event
      Returns:
      long; the payload

    • fireEvent

      protected short fireEvent​(EventType eventType, short value)
      Transmit an event with a short payload to all interested listeners.
      Parameters:
      eventType - EventType; the eventType of the event
      value - short; the payload
      Returns:
      short; the payload

    • fireTimedEvent

      protected <C extends Comparable<C> & Serializable> short fireTimedEvent​(EventType eventType, short value, C time)
      Transmit a time-stamped event with a short payload to all interested listeners.
      Type Parameters:
      C - the comparable type to indicate the time when the event is fired
      Parameters:
      eventType - EventType; the eventType of the event
      value - short; the payload
      time - C; a time stamp for the event
      Returns:
      short; the payload

    • removeAllListeners

      protected int removeAllListeners()
      Remove all the listeners from this event producer.
      Returns:
      int; the number of removed event types

    • removeAllListeners

      protected int removeAllListeners​(Class<?> ofClass)
      Removes all the listeners of a class from this event producer.
      Parameters:
      ofClass - Class<?>; the class or superclass
      Returns:
      int; the number of removed listeners

    • removeListener

      public final boolean removeListener​(EventListenerInterface listener, EventType eventType)
      Remove the subscription of a listener for a specific event.
      Specified by:
      removeListener in interface EventProducerInterface
      Parameters:
      listener - EventListenerInterface; which is no longer interested
      eventType - EventType; the event which is of no interest any more
      Returns:
      the success of removing the listener. If a listener was not subscribed false is returned

    • hasListeners

      public boolean hasListeners()
      Return whether the EventProducer has listeners.
      Specified by:
      hasListeners in interface EventProducerInterface
      Returns:
      boolean; whether the EventProducer has listeners or not

    • numberOfListeners

      public int numberOfListeners​(EventType eventType)
      Return the number of listeners for the provided EventType.
      Specified by:
      numberOfListeners in interface EventProducerInterface
      Parameters:
      eventType - EventType; the event type to return the number of listeners for
      Returns:
      boolean; whether the EventProducer has listeners or not

    • getEventTypesWithListeners

      public Set<EventType> getEventTypesWithListeners()
      Return the EventTypes for which the EventProducer has listeners.
      Specified by:
      getEventTypesWithListeners in interface EventProducerInterface
      Returns:
      Set<EventType>; the EventTypes for which the EventProducer has registered listeners

    • getListenerReferences

      protected List<Reference<EventListenerInterface>> getListenerReferences​(EventType eventType)
      Return a safe copy of the list of (strong or weak) references to the registered listeners for the provided event type, or an empty list when nothing is registered for this event type. The method never returns a null pointer, so it is safe to use the result directly in an iterator. The references to the listeners are the original references, so not safe copies.
      Parameters:
      eventType - EventType; the event type to look up the listeners for
      Returns:
      List<Reference<EventListenerInterface>>; the list of references to the listeners for this event type, or an empty list when the event type is not registered