001/*
002 * Copyright 2002-2016 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.messaging.simp.user;
018
019import java.util.Set;
020
021import org.springframework.lang.Nullable;
022
023/**
024 * A registry of currently connected users.
025 *
026 * @author Rossen Stoyanchev
027 * @since 4.2
028 */
029public interface SimpUserRegistry {
030
031        /**
032         * Get the user for the given name.
033         * @param userName the name of the user to look up
034         * @return the user, or {@code null} if not connected
035         */
036        @Nullable
037        SimpUser getUser(String userName);
038
039        /**
040         * Return a snapshot of all connected users.
041         * <p>The returned set is a copy and will not reflect further changes.
042         * @return the connected users, or an empty set if none
043         */
044        Set<SimpUser> getUsers();
045
046        /**
047         * Return the count of all connected users.
048         * @return the number of connected users
049         * @since 4.3.5
050         */
051        int getUserCount();
052
053        /**
054         * Find subscriptions with the given matcher.
055         * @param matcher the matcher to use
056         * @return a set of matching subscriptions, or an empty set if none
057         */
058        Set<SimpSubscription> findSubscriptions(SimpSubscriptionMatcher matcher);
059
060}