io.github.dronesecurity.userapplication.events.DomainEvents Maven / Gradle / Ivy
/*
* Copyright (c) 2021-2022, Mirko Felice & Maxim Derevyanchenko. All rights reserved.
* Licensed under the MIT license. See LICENSE file in the project root for details.
*/
package io.github.dronesecurity.userapplication.events;
import org.jetbrains.annotations.NotNull;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Consumer;
/**
* Manager class of all domain events.
*/
public final class DomainEvents {
private static final Map, List>> ALL_CONSUMERS =
new ConcurrentHashMap<>();
private DomainEvents() { }
/**
* Adds a handler to manage the arrival of an event.
* @param clazz {@link Class} of the {@link DomainEvent} to register on
* @param handler the {@link Consumer} to execute when an event is raised
* @param type parameter to constraint consuming only {@link DomainEvent} subclasses
*/
public static void register(final Class clazz, final Consumer handler) {
ALL_CONSUMERS.computeIfAbsent(clazz, k -> new ArrayList<>());
ALL_CONSUMERS.get(clazz).add(handler);
}
/**
* Removes a handler previously registered.
* @param clazz {@link Class} of the {@link DomainEvent} to unregister from
* @param handler the {@link Consumer} previously registered
* @param type parameter to constraint consuming only {@link DomainEvent} subclasses
*/
public static void unregister(final Class clazz, final Consumer handler) {
final List> consumers = ALL_CONSUMERS.get(clazz);
if (consumers != null && handler != null) {
consumers.remove(handler);
if (consumers.isEmpty())
ALL_CONSUMERS.remove(clazz);
}
}
/**
* Raises the event for the domain.
*
* @param event the new event
* @param type parameter to constraint raising only {@link DomainEvent} subclasses
*/
@SuppressWarnings("unchecked")
public static void raise(final @NotNull T event) {
final List> consumers =
List.copyOf(ALL_CONSUMERS.getOrDefault(event.getClass(), new ArrayList<>()));
for (final Consumer cons : consumers) {
((Consumer) cons).accept(event);
}
}
}