001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.activemq.broker.view;
018
019import java.util.HashMap;
020import java.util.Map;
021
022import org.apache.activemq.broker.BrokerRegistry;
023import org.apache.activemq.broker.BrokerService;
024
025public class MessageBrokerViewRegistry {
026
027    private static final MessageBrokerViewRegistry INSTANCE = new MessageBrokerViewRegistry();
028
029    private final Object mutex = new Object();
030    private final Map<String, MessageBrokerView> brokerViews = new HashMap<String, MessageBrokerView>();
031
032    public static MessageBrokerViewRegistry getInstance() {
033        return INSTANCE;
034    }
035
036    /**
037     * @param brokerName
038     * @return the BrokerService
039     */
040    public MessageBrokerView lookup(String brokerName) {
041        MessageBrokerView result = null;
042        synchronized (mutex) {
043            result = brokerViews.get(brokerName);
044            if (result==null){
045                BrokerService brokerService = BrokerRegistry.getInstance().lookup(brokerName);
046                if (brokerService != null){
047                    result = new MessageBrokerView(brokerService);
048                    brokerViews.put(brokerName,result);
049                }
050            }
051
052        }
053        return result;
054    }
055}