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     */
017    package org.apache.activemq.network;
018    
019    import java.util.Set;
020    import java.util.concurrent.CopyOnWriteArraySet;
021    import java.util.concurrent.atomic.AtomicBoolean;
022    import java.util.concurrent.atomic.AtomicInteger;
023    
024    import org.apache.activemq.command.ConsumerId;
025    import org.apache.activemq.command.ConsumerInfo;
026    import org.apache.activemq.command.NetworkBridgeFilter;
027    import org.slf4j.Logger;
028    import org.slf4j.LoggerFactory;
029    
030    /**
031     * Represents a network bridge interface
032     */
033    public class DemandSubscription {
034        private static final Logger LOG = LoggerFactory.getLogger(DemandSubscription.class);
035    
036        private final ConsumerInfo remoteInfo;
037        private final ConsumerInfo localInfo;
038        private final Set<ConsumerId> remoteSubsIds = new CopyOnWriteArraySet<ConsumerId>();
039        private final AtomicInteger dispatched = new AtomicInteger(0);
040        private final AtomicBoolean activeWaiter = new AtomicBoolean();
041    
042        private NetworkBridgeFilter networkBridgeFilter;
043    
044        DemandSubscription(ConsumerInfo info) {
045            remoteInfo = info;
046            localInfo = info.copy();
047            localInfo.setNetworkSubscription(true);
048            remoteSubsIds.add(info.getConsumerId());
049        }
050    
051        /**
052         * Increment the consumers associated with this subscription
053         *
054         * @param id
055         * @return true if added
056         */
057        public boolean add(ConsumerId id) {
058            return remoteSubsIds.add(id);
059        }
060    
061        /**
062         * Increment the consumers associated with this subscription
063         *
064         * @param id
065         * @return true if removed
066         */
067        public boolean remove(ConsumerId id) {
068            return remoteSubsIds.remove(id);
069        }
070    
071        /**
072         * @return true if there are no interested consumers
073         */
074        public boolean isEmpty() {
075            return remoteSubsIds.isEmpty();
076        }
077    
078        public int size() {
079            return remoteSubsIds.size();
080        }
081        /**
082         * @return Returns the localInfo.
083         */
084        public ConsumerInfo getLocalInfo() {
085            return localInfo;
086        }
087    
088        /**
089         * @return Returns the remoteInfo.
090         */
091        public ConsumerInfo getRemoteInfo() {
092            return remoteInfo;
093        }
094    
095        public void waitForCompletion() {
096            if (dispatched.get() > 0) {
097                if (LOG.isDebugEnabled()) {
098                    LOG.debug("Waiting for completion for sub: " + localInfo.getConsumerId() + ", dispatched: " + this.dispatched.get());
099                }
100                activeWaiter.set(true);
101                if (dispatched.get() > 0) {
102                    synchronized (activeWaiter) {
103                        try {
104                            activeWaiter.wait();
105                        } catch (InterruptedException ignored) {
106                        }
107                    }
108                    if (this.dispatched.get() > 0) {
109                        LOG.warn("demand sub interrupted or timedout while waiting for outstanding responses, " +
110                                 "expect potentially " + this.dispatched.get() + " duplicate deliveried");
111                    }
112                }
113            }
114        }
115    
116        public void decrementOutstandingResponses() {
117            if (dispatched.decrementAndGet() == 0 && activeWaiter.get()) {
118                synchronized (activeWaiter) {
119                    activeWaiter.notifyAll();
120                }
121            }
122        }
123    
124        public boolean incrementOutstandingResponses() {
125            dispatched.incrementAndGet();
126            if (activeWaiter.get()) {
127                decrementOutstandingResponses();
128                return false;
129            }
130            return true;
131        }
132    
133        public NetworkBridgeFilter getNetworkBridgeFilter() {
134            return networkBridgeFilter;
135        }
136    
137        public void setNetworkBridgeFilter(NetworkBridgeFilter networkBridgeFilter) {
138            this.networkBridgeFilter = networkBridgeFilter;
139        }
140    }