Subscriptions.java

/*****************************************************************************
 * Copyright 2013 Olivier Croquette <ocroquette@free.fr>                     *
 *                                                                           *
 *  Licensed under the Apache License, Version 2.0 (the "License");          *
 *  you may not use this file except in compliance with the License.         *
 *  You may obtain a copy of the License at                                  *
 *                                                                           *
 *      http://www.apache.org/licenses/LICENSE-2.0                           *
 *                                                                           *
 *  Unless required by applicable law or agreed to in writing, software      *
 *  distributed under the License is distributed on an "AS IS" BASIS,        *
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
 *  See the License for the specific language governing permissions and      *
 *  limitations under the License.                                           *
 ****************************************************************************/
package org.magnum.soda.server.wamp;

import java.util.Collections;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;


public class Subscriptions {

	public interface ActionOnSubscriber {
		void execute(ClientId clientId);
	}
	
	public Subscriptions() {
		subscriptions = new ConcurrentHashMap<String, Set<ClientId>>();
	}

	public void subscribe(ClientId clientId, String topicUri) {
		Set<ClientId> clientList = subscriptions.get(topicUri);
		if ( clientList == null ) {
			clientList = newClientSet();
			subscriptions.put(topicUri, clientList);
		}
		clientList.add(clientId);
	}

	public void unsubscribe(ClientId clientId, String topicUri) {
		Set<ClientId> clientList = subscriptions.get(topicUri);
		if ( clientList == null ) {
			return;
		}
		clientList.remove(clientId);
	}
	
	public long forAllSubscribers(String topic, ActionOnSubscriber action) {
		long performed = 0;
		Set<ClientId> set = subscriptions.get(topic);
		if (set == null)
			return performed;
		for (ClientId clientId: set) {
			action.execute(clientId);
			performed++;
		}
		return performed;
	}


	private Set<ClientId> newClientSet() {
		return Collections.newSetFromMap(new ConcurrentHashMap<ClientId, Boolean>());
	}
	
	protected Map<String, Set<ClientId>> subscriptions;
}