org.apache.commons.configuration2.event

Class EventType<T extends Event>

java.lang.Object

org.apache.commons.configuration2.event.EventType<T>

Type Parameters:

T - the event associated with this type

All Implemented Interfaces:

Serializable

public class EventType<T extends Event>
extends Object
implements 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

Version:

$Id: EventType.java 1842194 2018-09-27 22:24:23Z ggregory $

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
EventType(EventType<? super T> superEventType, String typeName) Creates a new instance of EventType and initializes it with the super type and a type name.

Method Summary

Modifier and Type	Method and Description
static Set<EventType<?>>	fetchSuperEventTypes(EventType<?> eventType) Returns a set with all event types that are super types of the specified type.
String	getName() Returns the name of this event type.
EventType<? super T>	getSuperType() Returns the super event type.
static boolean	isInstanceOf(EventType<?> derivedType, EventType<?> baseType) Checks whether an event type is derived from another type.
String	toString() Returns a string representation for this object.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

EventType

public EventType(EventType<? super T> superEventType,
                 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

getSuperType

public EventType<? super T> getSuperType()

Returns the super event type. Result is null for the root event type.

Returns:

the super event type

getName

public String getName()

Returns 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

toString

public 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 Object

Returns:

a string for this object

fetchSuperEventTypes

public static 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