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}