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/**
* 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.LinkedList;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
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.IndirectMessageReference;
import org.apache.activemq.broker.region.MessageReference;
import org.apache.activemq.broker.region.QueueMessageReference;
import org.apache.activemq.command.Message;
import org.apache.activemq.filter.NonCachedMessageEvaluationContext;
import org.apache.activemq.openwire.OpenWireFormat;
import org.apache.activemq.store.PList;
import org.apache.activemq.store.PListStore;
import org.apache.activemq.store.PListEntry;
import org.apache.activemq.usage.SystemUsage;
import org.apache.activemq.usage.Usage;
import org.apache.activemq.usage.UsageListener;
import org.apache.activemq.wireformat.WireFormat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.activemq.util.ByteSequence;
/**
* persist pending messages pending message (messages awaiting dispatch to a
* consumer) cursor
*
*
*/
public class FilePendingMessageCursor extends AbstractPendingMessageCursor implements UsageListener {
static final Logger LOG = LoggerFactory.getLogger(FilePendingMessageCursor.class);
private static final AtomicLong NAME_COUNT = new AtomicLong();
protected Broker broker;
private final PListStore store;
private final String name;
private PendingList memoryList;
private PList diskList;
private Iterator iter;
private Destination regionDestination;
private boolean iterating;
private boolean flushRequired;
private final AtomicBoolean started = new AtomicBoolean();
private final WireFormat wireFormat = new OpenWireFormat();
/**
* @param broker
* @param name
* @param prioritizedMessages
*/
public FilePendingMessageCursor(Broker broker, String name, boolean prioritizedMessages) {
super(prioritizedMessages);
if (this.prioritizedMessages) {
this.memoryList = new PrioritizedPendingList();
} else {
this.memoryList = new OrderedPendingList();
}
this.broker = broker;
// the store can be null if the BrokerService has persistence
// turned off
this.store = broker.getTempDataStore();
this.name = NAME_COUNT.incrementAndGet() + "_" + name;
}
@Override
public void start() throws Exception {
if (started.compareAndSet(false, true)) {
if( this.broker != null) {
wireFormat.setVersion(this.broker.getBrokerService().getStoreOpenWireVersion());
}
super.start();
if (systemUsage != null) {
systemUsage.getMemoryUsage().addUsageListener(this);
}
}
}
@Override
public void stop() throws Exception {
if (started.compareAndSet(true, false)) {
super.stop();
if (systemUsage != null) {
systemUsage.getMemoryUsage().removeUsageListener(this);
}
}
}
/**
* @return true if there are no pending messages
*/
@Override
public synchronized boolean isEmpty() {
if (memoryList.isEmpty() && isDiskListEmpty()) {
return true;
}
for (Iterator iterator = memoryList.iterator(); iterator.hasNext();) {
MessageReference node = iterator.next();
if (node == QueueMessageReference.NULL_MESSAGE) {
continue;
}
if (!node.isDropped()) {
return false;
}
// We can remove dropped references.
iterator.remove();
}
return isDiskListEmpty();
}
/**
* reset the cursor
*/
@Override
public synchronized void reset() {
iterating = true;
last = null;
if (isDiskListEmpty()) {
this.iter = this.memoryList.iterator();
} else {
this.iter = new DiskIterator();
}
}
@Override
public synchronized void release() {
iterating = false;
if (iter instanceof DiskIterator) {
((DiskIterator)iter).release();
};
if (flushRequired) {
flushRequired = false;
if (!hasSpace()) {
flushToDisk();
}
}
// ensure any memory ref is released
iter = null;
}
@Override
public synchronized void destroy() throws Exception {
stop();
for (Iterator i = memoryList.iterator(); i.hasNext();) {
MessageReference node = i.next();
node.decrementReferenceCount();
}
memoryList.clear();
destroyDiskList();
}
private void destroyDiskList() throws Exception {
if (diskList != null) {
store.removePList(name);
diskList = null;
}
}
@Override
public synchronized LinkedList pageInList(int maxItems) {
LinkedList result = new LinkedList();
int count = 0;
for (Iterator i = memoryList.iterator(); i.hasNext() && count < maxItems;) {
MessageReference ref = i.next();
ref.incrementReferenceCount();
result.add(ref);
count++;
}
if (count < maxItems && !isDiskListEmpty()) {
for (Iterator i = new DiskIterator(); i.hasNext() && count < maxItems;) {
Message message = (Message) i.next();
message.setRegionDestination(regionDestination);
message.setMemoryUsage(this.getSystemUsage().getMemoryUsage());
message.incrementReferenceCount();
result.add(message);
count++;
}
}
return result;
}
/**
* add message to await dispatch
*
* @param node
* @throws Exception
*/
@Override
public synchronized boolean addMessageLast(MessageReference node) throws Exception {
return tryAddMessageLast(node, 0);
}
@Override
public synchronized boolean tryAddMessageLast(MessageReference node, long maxWaitTime) throws Exception {
if (!node.isExpired()) {
try {
regionDestination = (Destination) node.getMessage().getRegionDestination();
if (isDiskListEmpty()) {
if (hasSpace() || this.store == null) {
memoryList.addMessageLast(node);
node.incrementReferenceCount();
setCacheEnabled(true);
return true;
}
}
if (!hasSpace()) {
if (isDiskListEmpty()) {
expireOldMessages();
if (hasSpace()) {
memoryList.addMessageLast(node);
node.incrementReferenceCount();
return true;
} else {
flushToDisk();
}
}
}
if (systemUsage.getTempUsage().waitForSpace(maxWaitTime)) {
ByteSequence bs = getByteSequence(node.getMessage());
getDiskList().addLast(node.getMessageId().toString(), bs);
return true;
}
return false;
} catch (Exception e) {
LOG.error("Caught an Exception adding a message: {} first to FilePendingMessageCursor ", node, e);
throw new RuntimeException(e);
}
} else {
discardExpiredMessage(node);
}
//message expired
return true;
}
/**
* add message to await dispatch
*
* @param node
*/
@Override
public synchronized void addMessageFirst(MessageReference node) {
if (!node.isExpired()) {
try {
regionDestination = (Destination) node.getMessage().getRegionDestination();
if (isDiskListEmpty()) {
if (hasSpace()) {
memoryList.addMessageFirst(node);
node.incrementReferenceCount();
setCacheEnabled(true);
return;
}
}
if (!hasSpace()) {
if (isDiskListEmpty()) {
expireOldMessages();
if (hasSpace()) {
memoryList.addMessageFirst(node);
node.incrementReferenceCount();
return;
} else {
flushToDisk();
}
}
}
systemUsage.getTempUsage().waitForSpace();
node.decrementReferenceCount();
ByteSequence bs = getByteSequence(node.getMessage());
Object locator = getDiskList().addFirst(node.getMessageId().toString(), bs);
node.getMessageId().setPlistLocator(locator);
} catch (Exception e) {
LOG.error("Caught an Exception adding a message: {} first to FilePendingMessageCursor ", node, e);
throw new RuntimeException(e);
}
} else {
discardExpiredMessage(node);
}
}
/**
* @return true if there pending messages to dispatch
*/
@Override
public synchronized boolean hasNext() {
return iter.hasNext();
}
/**
* @return the next pending message
*/
@Override
public synchronized MessageReference next() {
MessageReference reference = iter.next();
last = reference;
if (!isDiskListEmpty()) {
// got from disk
reference.getMessage().setRegionDestination(regionDestination);
reference.getMessage().setMemoryUsage(this.getSystemUsage().getMemoryUsage());
}
reference.incrementReferenceCount();
return reference;
}
/**
* remove the message at the cursor position
*/
@Override
public synchronized void remove() {
iter.remove();
if (last != null) {
last.decrementReferenceCount();
}
}
/**
* @param node
* @see org.apache.activemq.broker.region.cursors.AbstractPendingMessageCursor#remove(org.apache.activemq.broker.region.MessageReference)
*/
@Override
public synchronized void remove(MessageReference node) {
if (memoryList.remove(node) != null) {
node.decrementReferenceCount();
}
if (!isDiskListEmpty()) {
try {
getDiskList().remove(node.getMessageId().getPlistLocator());
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
/**
* @return the number of pending messages
*/
@Override
public synchronized int size() {
return memoryList.size() + (isDiskListEmpty() ? 0 : (int)getDiskList().size());
}
/**
* clear all pending messages
*/
@Override
public synchronized void clear() {
memoryList.clear();
if (!isDiskListEmpty()) {
try {
getDiskList().destroy();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
last = null;
}
@Override
public synchronized boolean isFull() {
return super.isFull() || (!isDiskListEmpty() && systemUsage != null && systemUsage.getTempUsage().isFull());
}
@Override
public boolean hasMessagesBufferedToDeliver() {
return !isEmpty();
}
@Override
public void setSystemUsage(SystemUsage usageManager) {
super.setSystemUsage(usageManager);
}
public void onUsageChanged(Usage usage, int oldPercentUsage, int newPercentUsage) {
if (newPercentUsage >= getMemoryUsageHighWaterMark()) {
synchronized (this) {
if (!flushRequired && size() != 0) {
flushRequired =true;
if (!iterating) {
expireOldMessages();
if (!hasSpace()) {
flushToDisk();
flushRequired = false;
}
}
}
}
}
}
@Override
public boolean isTransient() {
return true;
}
protected synchronized void expireOldMessages() {
if (!memoryList.isEmpty()) {
for (Iterator iterator = memoryList.iterator(); iterator.hasNext();) {
MessageReference node = iterator.next();
if (node.isExpired()) {
node.decrementReferenceCount();
discardExpiredMessage(node);
iterator.remove();
}
}
}
}
protected synchronized void flushToDisk() {
if (!memoryList.isEmpty() && store != null) {
long start = 0;
if (LOG.isTraceEnabled()) {
start = System.currentTimeMillis();
LOG.trace("{}, flushToDisk() mem list size: {} {}", new Object[]{ name, memoryList.size(), (systemUsage != null ? systemUsage.getMemoryUsage() : "") });
}
for (Iterator iterator = memoryList.iterator(); iterator.hasNext();) {
MessageReference node = iterator.next();
node.decrementReferenceCount();
ByteSequence bs;
try {
bs = getByteSequence(node.getMessage());
getDiskList().addLast(node.getMessageId().toString(), bs);
} catch (IOException e) {
LOG.error("Failed to write to disk list", e);
throw new RuntimeException(e);
}
}
memoryList.clear();
setCacheEnabled(false);
LOG.trace("{}, flushToDisk() done - {} ms {}", new Object[]{ name, (System.currentTimeMillis() - start), (systemUsage != null ? systemUsage.getMemoryUsage() : "") });
}
}
protected boolean isDiskListEmpty() {
return diskList == null || diskList.isEmpty();
}
public PList getDiskList() {
if (diskList == null) {
try {
diskList = store.getPList(name);
} catch (Exception e) {
LOG.error("Caught an IO Exception getting the DiskList {}", name, e);
throw new RuntimeException(e);
}
}
return diskList;
}
private void discardExpiredMessage(MessageReference reference) {
LOG.debug("Discarding expired message {}", reference);
if (broker.isExpired(reference)) {
ConnectionContext context = new ConnectionContext(new NonCachedMessageEvaluationContext());
context.setBroker(broker);
((Destination)reference.getRegionDestination()).messageExpired(context, null, new IndirectMessageReference(reference.getMessage()));
}
}
protected ByteSequence getByteSequence(Message message) throws IOException {
org.apache.activemq.util.ByteSequence packet = wireFormat.marshal(message);
return new ByteSequence(packet.data, packet.offset, packet.length);
}
protected Message getMessage(ByteSequence bs) throws IOException {
org.apache.activemq.util.ByteSequence packet = new org.apache.activemq.util.ByteSequence(bs.getData(), bs
.getOffset(), bs.getLength());
return (Message) this.wireFormat.unmarshal(packet);
}
final class DiskIterator implements Iterator {
private final PList.PListIterator iterator;
DiskIterator() {
try {
iterator = getDiskList().iterator();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public boolean hasNext() {
return iterator.hasNext();
}
public MessageReference next() {
try {
PListEntry entry = iterator.next();
Message message = getMessage(entry.getByteSequence());
message.getMessageId().setPlistLocator(entry.getLocator());
return message;
} catch (IOException e) {
LOG.error("I/O error", e);
throw new RuntimeException(e);
}
}
public void remove() {
iterator.remove();
}
public void release() {
iterator.release();
}
}
}