/**
* 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.io.IOException;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import org.apache.activemq.broker.region.Destination;
import org.apache.activemq.broker.region.MessageReference;
import org.apache.activemq.broker.region.Subscription;
import org.apache.activemq.broker.region.Topic;
import org.apache.activemq.command.Message;
import org.apache.activemq.command.MessageId;
import org.apache.activemq.filter.MessageEvaluationContext;
import org.apache.activemq.store.MessageRecoveryListener;
import org.apache.activemq.store.TopicMessageStore;
import org.apache.activemq.usage.SystemUsage;
import org.apache.activemq.usage.Usage;
import org.apache.activemq.usage.UsageListener;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* perist pendingCount messages pendingCount message (messages awaiting disptach
* to a consumer) cursor
*
* @version $Revision: 599129 $
*/
class TopicStorePrefetch extends AbstractPendingMessageCursor implements MessageRecoveryListener, UsageListener {
private static final Log LOG = LogFactory.getLog(TopicStorePrefetch.class);
private TopicMessageStore store;
private final LinkedHashMap<MessageId,Message> batchList = new LinkedHashMap<MessageId,Message> ();
private String clientId;
private String subscriberName;
private Destination regionDestination;
private boolean batchResetNeeded = true;
private boolean storeMayHaveMoreMessages = true;
private boolean started;
private final Subscription subscription;
/**
* @param topic
* @param clientId
* @param subscriberName
*/
public TopicStorePrefetch(Topic topic, String clientId, String subscriberName, Subscription subscription) {
this.regionDestination = topic;
this.subscription = subscription;
this.store = (TopicMessageStore)topic.getMessageStore();
this.clientId = clientId;
this.subscriberName = subscriberName;
this.maxProducersToAudit=32;
this.maxAuditDepth=10000;
}
public synchronized void start() throws Exception {
if (!started) {
started = true;
super.start();
getSystemUsage().getMemoryUsage().addUsageListener(this);
safeFillBatch();
}
}
public synchronized void stop() throws Exception {
if (started) {
started = false;
getSystemUsage().getMemoryUsage().removeUsageListener(this);
super.stop();
store.resetBatching(clientId, subscriberName);
gc();
}
}
/**
* @return true if there are no pendingCount messages
*/
public synchronized boolean isEmpty() {
safeFillBatch();
return batchList.isEmpty();
}
public synchronized int size() {
safeFillBatch();
return batchList.size();
}
public synchronized void addMessageLast(MessageReference node) throws Exception {
if (node != null) {
storeMayHaveMoreMessages=true;
node.decrementReferenceCount();
}
}
public synchronized void addMessageFirst(MessageReference node) throws Exception {
if (node != null) {
storeMayHaveMoreMessages=true;
node.decrementReferenceCount();
rollback(node.getMessageId());
}
}
public synchronized void remove() {
}
public synchronized void remove(MessageReference node) {
}
public synchronized void clear() {
gc();
}
public synchronized boolean hasNext() {
boolean result = !isEmpty();
return result;
}
public synchronized MessageReference next() {
Message result = null;
safeFillBatch();
if (batchList.isEmpty()) {
return null;
} else {
Iterator i = batchList.entrySet().iterator();
result = (Message) ((Map.Entry)i.next()).getValue();
i.remove();
result.setRegionDestination(regionDestination);
result.setMemoryUsage(this.getSystemUsage().getMemoryUsage());
}
return result;
}
public void reset() {
}
// MessageRecoveryListener implementation
public void finished() {
}
public synchronized boolean recoverMessage(Message message)
throws Exception {
MessageEvaluationContext messageEvaluationContext = new MessageEvaluationContext();
messageEvaluationContext.setMessageReference(message);
if (subscription.matches(message, messageEvaluationContext)) {
message.setRegionDestination(regionDestination);
if (!isDuplicate(message.getMessageId())) {
// only increment if count is zero (could have been cached)
if (message.getReferenceCount() == 0) {
message.setMemoryUsage(this.getSystemUsage().getMemoryUsage());
message.incrementReferenceCount();
}
batchList.put(message.getMessageId(), message);
}else {
this.storeMayHaveMoreMessages=true;
}
}
return true;
}
public boolean recoverMessageReference(MessageId messageReference) throws Exception {
// shouldn't get called
throw new RuntimeException("Not supported");
}
/**
* Mark a message as already dispatched
* @param message
*/
public synchronized void dispatched(MessageReference message) {
if (this.audit != null) {
isDuplicate(message.getMessageId());
Message removed = this.batchList.remove(message.getMessageId());
if (removed != null) {
removed.decrementReferenceCount();
}
}
}
// implementation
protected synchronized void safeFillBatch() {
try {
fillBatch();
} catch (Exception e) {
LOG.error("Failed to fill batch", e);
throw new RuntimeException(e);
}
}
protected synchronized void fillBatch() throws Exception {
if (batchResetNeeded) {
this.store.resetBatching(clientId, subscriberName);
this.batchResetNeeded = false;
this.storeMayHaveMoreMessages = true;
}
while (this.batchList.isEmpty() && this.storeMayHaveMoreMessages) {
this.storeMayHaveMoreMessages = false;
this.store.recoverNextMessages(clientId, subscriberName,
maxBatchSize, this);
if (!this.batchList.isEmpty()) {
this.storeMayHaveMoreMessages=true;
}
}
}
protected synchronized int getStoreSize() {
try {
return store.getMessageCount(clientId, subscriberName);
} catch (IOException e) {
LOG.error(this + " Failed to get the outstanding message count from the store", e);
throw new RuntimeException(e);
}
}
public synchronized void gc() {
for (Message msg : batchList.values()) {
msg.decrementReferenceCount();
}
batchList.clear();
batchResetNeeded = true;
}
public void onUsageChanged(Usage usage, int oldPercentUsage,int newPercentUsage) {
if (oldPercentUsage > newPercentUsage && oldPercentUsage >= 90) {
storeMayHaveMoreMessages = true;
try {
fillBatch();
} catch (Exception e) {
LOG.error("Failed to fill batch ", e);
}
}
}
public String toString() {
return "TopicStorePrefetch" + System.identityHashCode(this) + "(" + clientId + "," + subscriberName + ")";
}
}