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}