2 * Copyright (c) 2013 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.yangtools.util;
10 import static java.util.Objects.requireNonNull;
12 import com.google.common.base.MoreObjects;
13 import java.util.Collections;
14 import java.util.EventListener;
16 import java.util.concurrent.ConcurrentHashMap;
17 import java.util.function.Consumer;
18 import java.util.stream.Stream;
19 import org.eclipse.jdt.annotation.NonNull;
20 import org.opendaylight.yangtools.concepts.AbstractListenerRegistration;
21 import org.opendaylight.yangtools.concepts.ListenerRegistration;
22 import org.opendaylight.yangtools.concepts.Mutable;
25 * A registry of EventListeners, maintaining a set of registrations. This class is thread-safe.
27 * @param <T> Type of listeners this registry handles
29 public final class ListenerRegistry<T extends EventListener> implements Mutable {
31 private final Set<ListenerRegistration<? extends T>> listeners = ConcurrentHashMap.newKeySet();
32 // This conversion is known to be safe.
33 @SuppressWarnings({ "rawtypes", "unchecked" })
34 private final Set<ListenerRegistration<T>> unmodifiableView = (Set) Collections.unmodifiableSet(listeners);
36 private final String name;
38 private ListenerRegistry(final String name) {
42 public static <T extends EventListener> @NonNull ListenerRegistry<T> create() {
43 return new ListenerRegistry<>(null);
46 public static <T extends EventListener> @NonNull ListenerRegistry<T> create(final @NonNull String name) {
47 return new ListenerRegistry<>(requireNonNull(name));
50 @Deprecated(forRemoval = true)
51 public @NonNull Set<? extends ListenerRegistration<? extends T>> getRegistrations() {
52 return unmodifiableView;
56 listeners.stream().forEach(ListenerRegistration::close);
59 public boolean isEmpty() {
60 return listeners.isEmpty();
63 public Stream<? extends T> streamListeners() {
64 return listeners.stream().map(ListenerRegistration::getInstance);
67 public <L extends T> @NonNull ListenerRegistration<L> register(final L listener) {
68 final ListenerRegistration<L> ret = new ListenerRegistrationImpl<>(listener, listeners::remove);
74 public String toString() {
75 return MoreObjects.toStringHelper(this).omitNullValues()
77 .add("size", listeners.size())
81 private static final class ListenerRegistrationImpl<T extends EventListener>
82 extends AbstractListenerRegistration<T> {
83 private Consumer<ListenerRegistration<? super T>> removeCall;
85 ListenerRegistrationImpl(final T instance, final Consumer<ListenerRegistration<? super T>> removeCall) {
87 this.removeCall = requireNonNull(removeCall);
91 protected void removeRegistration() {
92 removeCall.accept(this);
93 // Do not retain reference to that state