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ActiveMQ example source code file (StoreDurableSubscriberCursor.java)

This example ActiveMQ source code file (StoreDurableSubscriberCursor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - ActiveMQ tags/keywords

destination, durabletopicsubscription, exception, exception, list, message, override, override, pendingmessagecursor, pendingmessagecursor, string, threading, threads, topicstoreprefetch, topicstoreprefetch, unknown, util

The ActiveMQ StoreDurableSubscriberCursor.java source code

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.activemq.broker.region.cursors;

import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CopyOnWriteArrayList;
import org.apache.activemq.advisory.AdvisorySupport;
import org.apache.activemq.broker.Broker;
import org.apache.activemq.broker.ConnectionContext;
import org.apache.activemq.broker.region.Destination;
import org.apache.activemq.broker.region.DurableTopicSubscription;
import org.apache.activemq.broker.region.MessageReference;
import org.apache.activemq.broker.region.Topic;
import org.apache.activemq.command.Message;
import org.apache.activemq.usage.SystemUsage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * persist pending messages pending message (messages awaiting dispatch to a
 * consumer) cursor
 * 
 * 
 */
public class StoreDurableSubscriberCursor extends AbstractPendingMessageCursor {

    private static final Logger LOG = LoggerFactory.getLogger(StoreDurableSubscriberCursor.class);
    private static final int UNKNOWN = -1;
    private final String clientId;
    private final String subscriberName;
    private final Map<Destination, TopicStorePrefetch> topics = new HashMap();
    private final List<PendingMessageCursor> storePrefetches = new CopyOnWriteArrayList();
    private final PendingMessageCursor nonPersistent;
    private PendingMessageCursor currentCursor;
    private final DurableTopicSubscription subscription;
    private int cacheCurrentLowestPriority = UNKNOWN;
    private boolean immediatePriorityDispatch = true;
    /**
     * @param broker Broker for this cursor
     * @param clientId clientId for this cursor
     * @param subscriberName subscriber name for this cursor
     * @param maxBatchSize currently ignored
     * @param subscription  subscription for this cursor
     */
    public StoreDurableSubscriberCursor(Broker broker,String clientId, String subscriberName,int maxBatchSize, DurableTopicSubscription subscription) {
        super(AbstractPendingMessageCursor.isPrioritizedMessageSubscriber(broker,subscription));
        this.subscription=subscription;
        this.clientId = clientId;
        this.subscriberName = subscriberName;
        if (broker.getBrokerService().isPersistent()) {
            this.nonPersistent = new FilePendingMessageCursor(broker,clientId + subscriberName,this.prioritizedMessages);
        } else {
            this.nonPersistent = new VMPendingMessageCursor(this.prioritizedMessages);
        }
        
        this.nonPersistent.setMaxBatchSize(maxBatchSize);
        this.nonPersistent.setSystemUsage(systemUsage);
        this.storePrefetches.add(this.nonPersistent);

        if (prioritizedMessages) {
            setMaxAuditDepth(10*getMaxAuditDepth());
        }
    }

    @Override
    public synchronized void start() throws Exception {
        if (!isStarted()) {
            super.start();
            for (PendingMessageCursor tsp : storePrefetches) {
            	tsp.setMessageAudit(getMessageAudit());
                tsp.start();
            }
        }
    }

    @Override
    public synchronized void stop() throws Exception {
        if (isStarted()) {
            if (subscription.isKeepDurableSubsActive()) {
                super.gc();
                super.getMessageAudit().clear();
                for (PendingMessageCursor tsp : storePrefetches) {
                    tsp.gc();
                    tsp.getMessageAudit().clear();
                }
            } else {
                super.stop();
                for (PendingMessageCursor tsp : storePrefetches) {
                    tsp.stop();
                }
            }
        }
    }

    /**
     * Add a destination
     * 
     * @param context
     * @param destination
     * @throws Exception
     */
    @Override
    public synchronized void add(ConnectionContext context, Destination destination) throws Exception {
        if (destination != null && !AdvisorySupport.isAdvisoryTopic(destination.getActiveMQDestination())) {
            TopicStorePrefetch tsp = new TopicStorePrefetch(this.subscription,(Topic)destination, clientId, subscriberName);
            tsp.setMaxBatchSize(destination.getMaxPageSize());
            tsp.setSystemUsage(systemUsage);
            tsp.setMessageAudit(getMessageAudit());
            tsp.setEnableAudit(isEnableAudit());
            tsp.setMemoryUsageHighWaterMark(getMemoryUsageHighWaterMark());
            topics.put(destination, tsp);
            storePrefetches.add(tsp);
            if (isStarted()) {
                tsp.start();
            }
        }
    }

    /**
     * remove a destination
     * 
     * @param context
     * @param destination
     * @throws Exception
     */
    @Override
    public synchronized List<MessageReference> remove(ConnectionContext context, Destination destination) throws Exception {
        PendingMessageCursor tsp = topics.remove(destination);
        if (tsp != null) {
            storePrefetches.remove(tsp);
        }
        return Collections.EMPTY_LIST;
    }

    /**
     * @return true if there are no pending messages
     */
    @Override
    public synchronized boolean isEmpty() {
        for (PendingMessageCursor tsp : storePrefetches) {
            if( !tsp.isEmpty() )
                return false;
        }
        return true;
    }

    @Override
    public synchronized boolean isEmpty(Destination destination) {
        boolean result = true;
        TopicStorePrefetch tsp = topics.get(destination);
        if (tsp != null) {
            result = tsp.isEmpty();
        }
        return result;
    }

    /**
     * Informs the Broker if the subscription needs to intervention to recover
     * it's state e.g. DurableTopicSubscriber may do
     * 
     * @see org.apache.activemq.broker.region.cursors.AbstractPendingMessageCursor
     * @return true if recovery required
     */
    @Override
    public boolean isRecoveryRequired() {
        return false;
    }

    @Override
    public synchronized void addMessageLast(MessageReference node) throws Exception {
        if (node != null) {
            Message msg = node.getMessage();
            if (isStarted()) {
                if (!msg.isPersistent()) {
                    nonPersistent.addMessageLast(node);
                }
            }
            if (msg.isPersistent()) {
                Destination dest = msg.getRegionDestination();
                TopicStorePrefetch tsp = topics.get(dest);
                if (tsp != null) {
                    // cache can become high priority cache for immediate dispatch
                    final int priority = msg.getPriority();
                    if (isStarted() && this.prioritizedMessages && immediatePriorityDispatch && !tsp.isCacheEnabled()) {
                        if (priority > tsp.getCurrentLowestPriority()) {
                            if (LOG.isTraceEnabled()) {
                                LOG.trace("enabling cache for cursor on high priority message " + priority
                                        + ", current lowest: " + tsp.getCurrentLowestPriority());
                            }
                            tsp.setCacheEnabled(true);
                            cacheCurrentLowestPriority = tsp.getCurrentLowestPriority();
                        }
                    } else if (cacheCurrentLowestPriority != UNKNOWN && priority <= cacheCurrentLowestPriority) {
                        // go to the store to get next priority message as lower priority messages may be recovered
                        // already and need to acked sequence order
                        if (LOG.isTraceEnabled()) {
                            LOG.trace("disabling/clearing cache for cursor on lower priority message "
                                    + priority + ", tsp current lowest: " + tsp.getCurrentLowestPriority()
                                    + " cache lowest: " + cacheCurrentLowestPriority);
                        }
                        tsp.setCacheEnabled(false);
                        cacheCurrentLowestPriority = UNKNOWN;
                    }
                    tsp.addMessageLast(node);
                }
            }

        }
    }

    @Override
    public boolean isTransient() {
        return subscription.isKeepDurableSubsActive();
    }

    @Override
    public void addMessageFirst(MessageReference node) throws Exception {
        // for keep durable subs active, need to deal with redispatch
        if (node != null) {
            Message msg = node.getMessage();
            if (!msg.isPersistent()) {
                nonPersistent.addMessageFirst(node);
            } else {
                Destination dest = msg.getRegionDestination();
                TopicStorePrefetch tsp = topics.get(dest);
                if (tsp != null) {
                    tsp.addMessageFirst(node);
                }
            }
        }
    }

    @Override
    public synchronized void addRecoveredMessage(MessageReference node) throws Exception {
        nonPersistent.addMessageLast(node);
    }

    @Override
    public synchronized void clear() {
        for (PendingMessageCursor tsp : storePrefetches) {
            tsp.clear();
        }
    }

    @Override
    public synchronized boolean hasNext() {
        boolean result = true;
        if (result) {
            try {
                currentCursor = getNextCursor();
            } catch (Exception e) {
                LOG.error("Failed to get current cursor ", e);
                throw new RuntimeException(e);
            }
            result = currentCursor != null ? currentCursor.hasNext() : false;
        }
        return result;
    }

    @Override
    public synchronized MessageReference next() {
        MessageReference result = currentCursor != null ? currentCursor.next() : null;
        return result;
    }

    @Override
    public synchronized void remove() {
        if (currentCursor != null) {
            currentCursor.remove();
        }
    }

    @Override
    public synchronized void remove(MessageReference node) {
        if (currentCursor != null) {
            currentCursor.remove(node);
        }
    }

    @Override
    public synchronized void reset() {
        for (PendingMessageCursor storePrefetch : storePrefetches) {
            storePrefetch.reset();
        }
    }

    @Override
    public synchronized void release() {
        for (PendingMessageCursor storePrefetch : storePrefetches) {
            storePrefetch.release();
        }
    }

    @Override
    public synchronized int size() {
        int pendingCount=0;
        for (PendingMessageCursor tsp : storePrefetches) {
            pendingCount += tsp.size();
        }
        return pendingCount;
    }

    @Override
    public void setMaxBatchSize(int newMaxBatchSize) {
        for (PendingMessageCursor storePrefetch : storePrefetches) {
            storePrefetch.setMaxBatchSize(newMaxBatchSize);
        }
        super.setMaxBatchSize(newMaxBatchSize);
    }

    @Override
    public synchronized void gc() {
        for (PendingMessageCursor tsp : storePrefetches) {
            tsp.gc();
        }
        cacheCurrentLowestPriority = UNKNOWN;
    }

    @Override
    public void setSystemUsage(SystemUsage usageManager) {
        super.setSystemUsage(usageManager);
        for (PendingMessageCursor tsp : storePrefetches) {
            tsp.setSystemUsage(usageManager);
        }
    }
    
    @Override
    public void setMemoryUsageHighWaterMark(int memoryUsageHighWaterMark) {
        super.setMemoryUsageHighWaterMark(memoryUsageHighWaterMark);
        for (PendingMessageCursor cursor : storePrefetches) {
            cursor.setMemoryUsageHighWaterMark(memoryUsageHighWaterMark);
        }
    }
    
    @Override
    public void setMaxProducersToAudit(int maxProducersToAudit) {
        super.setMaxProducersToAudit(maxProducersToAudit);
        for (PendingMessageCursor cursor : storePrefetches) {
            cursor.setMaxAuditDepth(maxAuditDepth);
        }
    }

    @Override
    public void setMaxAuditDepth(int maxAuditDepth) {
        super.setMaxAuditDepth(maxAuditDepth);
        for (PendingMessageCursor cursor : storePrefetches) {
            cursor.setMaxAuditDepth(maxAuditDepth);
        }
    }
    
    @Override
    public void setEnableAudit(boolean enableAudit) {
        super.setEnableAudit(enableAudit);
        for (PendingMessageCursor cursor : storePrefetches) {
            cursor.setEnableAudit(enableAudit);
        }
    }
    
    @Override
    public  void setUseCache(boolean useCache) {
        super.setUseCache(useCache);
        for (PendingMessageCursor cursor : storePrefetches) {
            cursor.setUseCache(useCache);
        }
    }
    
    protected synchronized PendingMessageCursor getNextCursor() throws Exception {
        if (currentCursor == null || currentCursor.isEmpty()) {
            currentCursor = null;
            for (PendingMessageCursor tsp : storePrefetches) {
                if (tsp.hasNext()) {
                    currentCursor = tsp;
                    break;
                }
            }
            // round-robin
            if (storePrefetches.size()>1) {
                PendingMessageCursor first = storePrefetches.remove(0);
                storePrefetches.add(first);
            }
        }
        return currentCursor;
    }
    
    @Override
    public String toString() {
        return "StoreDurableSubscriber(" + clientId + ":" + subscriberName + ")";
    }

    public boolean isImmediatePriorityDispatch() {
        return immediatePriorityDispatch;
    }

    public void setImmediatePriorityDispatch(boolean immediatePriorityDispatch) {
        this.immediatePriorityDispatch = immediatePriorityDispatch;
    }

}

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