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; 018 019import java.util.concurrent.atomic.AtomicReference; 020 021/** 022 * Like a BrokerFilter but it allows you to switch the getNext().broker. This 023 * has more overhead than a BrokerFilter since access to the getNext().broker 024 * has to synchronized since it is mutable 025 * 026 * 027 */ 028public class MutableBrokerFilter extends BrokerFilter { 029 030 protected AtomicReference<Broker> next = new AtomicReference<Broker>(); 031 032 public MutableBrokerFilter(Broker next) { 033 super(null); // prevent future code from using the inherited 'next' 034 this.next.set(next); 035 } 036 037 @Override 038 public Broker getAdaptor(Class<?> type) { 039 if (type.isInstance(this)) { 040 return this; 041 } 042 return next.get().getAdaptor(type); 043 } 044 045 public Broker getNext() { 046 return next.get(); 047 } 048 049 public void setNext(Broker next) { 050 this.next.set(next); 051 } 052 053}