Class EventType<T extends Event>

  • Type Parameters:
    T - the event associated with this type
    All Implemented Interfaces:
    java.io.Serializable

    public class EventType<T extends Event>
    extends java.lang.Object
    implements java.io.Serializable

    A class representing an event type.

    The events produced by Commons Configuration all have a specific type. The event type can be used to determine the meaning of a specific event. It also acts as filter criterion when event listeners are registered. The listener is then called only for events of this type or derived types. The events in this library form a natural hierarchy with base types and more specialized types. By specifying an appropriate event type at listener registration time, it can be determined on a fine-granular basis which events are propagated to the listener.

    Note: Users familiar with JavaFX probably recognize this approach to event handling. It allows for generic event listener interfaces and a natural selection of events to be processed.

    Since:
    2.0
    See Also:
    Serialized Form
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private static java.lang.String FMT_TO_STRING
      Constant for the format used by toString().
      private java.lang.String name
      A name for this event type.
      private static long serialVersionUID
      Serial version UID.
      private EventType<? super T> superType
      Stores the super type of this type.
    • Constructor Summary

      Constructors 
      Constructor Description
      EventType​(EventType<? super T> superEventType, java.lang.String typeName)
      Creates a new instance of EventType and initializes it with the super type and a type name.
    • Field Detail

      • serialVersionUID

        private static final long serialVersionUID
        Serial version UID.
        See Also:
        Constant Field Values
      • FMT_TO_STRING

        private static final java.lang.String FMT_TO_STRING
        Constant for the format used by toString().
        See Also:
        Constant Field Values
      • superType

        private final EventType<? super T extends Event> superType
        Stores the super type of this type.
      • name

        private final java.lang.String name
        A name for this event type.
    • Constructor Detail

      • EventType

        public EventType​(EventType<? super T> superEventType,
                         java.lang.String typeName)
        Creates a new instance of EventType and initializes it with the super type and a type name. If no super type is specified, this is the root event type.
        Parameters:
        superEventType - the super event type
        typeName - the name of this event type
    • Method Detail

      • fetchSuperEventTypes

        public static java.util.Set<EventType<?>> fetchSuperEventTypes​(EventType<?> eventType)
        Returns a set with all event types that are super types of the specified type. This set contains the direct and indirect super types and also includes the given type itself. The passed in type may be null, then an empty set is returned.
        Parameters:
        eventType - the event type in question
        Returns:
        a set with all super event types
      • isInstanceOf

        public static boolean isInstanceOf​(EventType<?> derivedType,
                                           EventType<?> baseType)
        Checks whether an event type is derived from another type. This implementation tests whether baseType is a direct or indirect super type of derivedType. If one of the types is null, result is false.
        Parameters:
        derivedType - the derived event type
        baseType - the base event type
        Returns:
        true if the derived type is an instance of the base type, false otherwise
      • getName

        public java.lang.String getName()
        Gets the name of this event type. The name has no specific semantic meaning. It is just used for debugging purposes and also part of the string representation of this event type.
        Returns:
        the event type name
      • getSuperType

        public EventType<? super T> getSuperType()
        Gets the super event type. Result is null for the root event type.
        Returns:
        the super event type
      • toString

        public java.lang.String toString()
        Returns a string representation for this object. This method is mainly overridden for debugging purposes. The returned string contains the name of this event type.
        Overrides:
        toString in class java.lang.Object
        Returns:
        a string for this object