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
021/**
022 * A registry of currently connected users.
023 *
024 * @author Rossen Stoyanchev
025 * @since 4.2
026 */
027public interface SimpUserRegistry {
028
029        /**
030         * Get the user for the given name.
031         * @param userName the name of the user to look up
032         * @return the user, or {@code null} if not connected
033         */
034        SimpUser getUser(String userName);
035
036        /**
037         * Return a snapshot of all connected users.
038         * <p>The returned set is a copy and will not reflect further changes.
039         * @return the connected users, or an empty set if none
040         */
041        Set<SimpUser> getUsers();
042
043        /**
044         * Return the count of all connected users.
045         * @return the number of connected users
046         * @since 4.3.5
047         */
048        int getUserCount();
049
050        /**
051         * Find subscriptions with the given matcher.
052         * @param matcher the matcher to use
053         * @return a set of matching subscriptions, or an empty set if none
054         */
055        Set<SimpSubscription> findSubscriptions(SimpSubscriptionMatcher matcher);
056
057}