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本文主要研究一下artemis的duplicateProperty
Message
activemq-artemis-2.11.0/artemis-core-client/src/main/java/org/apache/activemq/artemis/api/core/Message.java
public interface Message {
//......
default Object getDuplicateProperty() {
return null;
}
default byte[] getDuplicateIDBytes() {
Object duplicateID = getDuplicateProperty();
if (duplicateID == null) {
return null;
} else {
if (duplicateID instanceof SimpleString) {
return ((SimpleString) duplicateID).getData();
} else if (duplicateID instanceof String) {
return new SimpleString(duplicateID.toString()).getData();
} else {
return (byte[]) duplicateID;
}
}
}
//......
}
- Message接口定义了getDuplicateProperty、getDuplicateIDBytes方法，其中getDuplicateIDBytes方法会读取getDuplicateProperty的值，然后转换为byte数组
CoreMessage
activemq-artemis-2.11.0/artemis-core-client/src/main/java/org/apache/activemq/artemis/core/message/impl/CoreMessage.java
public class CoreMessage extends RefCountMessage implements ICoreMessage {
//......
public Object getDuplicateProperty() {
return getObjectProperty(Message.HDR_DUPLICATE_DETECTION_ID);
}
//......
}
- CoreMessage实现了ICoreMessage接口，而ICoreMessage接口继承了Message接口；它的getDuplicateProperty方法会取Message.HDR_DUPLICATE_DETECTION_ID属性的值
checkDuplicateID
activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/postoffice/impl/PostOfficeImpl.java
public class PostOfficeImpl implements PostOffice, NotificationListener, BindingsFactory {
//......
private final ConcurrentMap<SimpleString, DuplicateIDCache> duplicateIDCaches = new ConcurrentHashMap<>();
//......
public RoutingStatus route(final Message message,
final RoutingContext context,
final boolean direct,
boolean rejectDuplicates,
final Binding bindingMove) throws Exception {
RoutingStatus result;
// Sanity check
if (message.getRefCount() > 0) {
throw new IllegalStateException("Message cannot be routed more than once");
}
final SimpleString address = context.getAddress(message);
setPagingStore(address, message);
AtomicBoolean startedTX = new AtomicBoolean(false);
applyExpiryDelay(message, address);
if (context.isDuplicateDetection() && !checkDuplicateID(message, context, rejectDuplicates, startedTX)) {
return RoutingStatus.DUPLICATED_ID;
}
message.clearInternalProperties();
Bindings bindings = addressManager.getBindingsForRoutingAddress(address);
AddressInfo addressInfo = addressManager.getAddressInfo(address);
//......
if (server.hasBrokerMessagePlugins()) {
server.callBrokerMessagePlugins(plugin -> plugin.afterMessageRoute(message, context, direct, rejectDuplicates, result));
}
return result;
}
private boolean checkDuplicateID(final Message message,
final RoutingContext context,
boolean rejectDuplicates,
AtomicBoolean startedTX) throws Exception {
// Check the DuplicateCache for the Bridge first
Object bridgeDup = message.removeExtraBytesProperty(Message.HDR_BRIDGE_DUPLICATE_ID);
if (bridgeDup != null) {
// if the message is being sent from the bridge, we just ignore the duplicate id, and use the internal one
byte[] bridgeDupBytes = (byte[]) bridgeDup;
DuplicateIDCache cacheBridge = getDuplicateIDCache(BRIDGE_CACHE_STR.concat(context.getAddress(message).toString()));
if (context.getTransaction() == null) {
context.setTransaction(new TransactionImpl(storageManager));
startedTX.set(true);
}
if (!cacheBridge.atomicVerify(bridgeDupBytes, context.getTransaction())) {
context.getTransaction().rollback();
startedTX.set(false);
message.decrementRefCount();
return false;
}
} else {
// if used BridgeDuplicate, it's not going to use the regular duplicate
// since this will would break redistribution (re-setting the duplicateId)
byte[] duplicateIDBytes = message.getDuplicateIDBytes();
DuplicateIDCache cache = null;
boolean isDuplicate = false;
if (duplicateIDBytes != null) {
cache = getDuplicateIDCache(context.getAddress(message));
isDuplicate = cache.contains(duplicateIDBytes);
if (rejectDuplicates && isDuplicate) {
ActiveMQServerLogger.LOGGER.duplicateMessageDetected(message);
String warnMessage = "Duplicate message detected - message will not be routed. Message information:" + message.toString();
if (context.getTransaction() != null) {
context.getTransaction().markAsRollbackOnly(new ActiveMQDuplicateIdException(warnMessage));
}
message.decrementRefCount();
return false;
}
}
if (cache != null && !isDuplicate) {
if (context.getTransaction() == null) {
// We need to store the duplicate id atomically with the message storage, so we need to create a tx for this
context.setTransaction(new TransactionImpl(storageManager));
startedTX.set(true);
}
cache.addToCache(duplicateIDBytes, context.getTransaction(), startedTX.get());
}
}
return true;
}
public DuplicateIDCache getDuplicateIDCache(final SimpleString address) {
DuplicateIDCache cache = duplicateIDCaches.get(address);
if (cache == null) {
cache = new DuplicateIDCacheImpl(address, idCacheSize, storageManager, persistIDCache);
DuplicateIDCache oldCache = duplicateIDCaches.putIfAbsent(address, cache);
if (oldCache != null) {
cache = oldCache;
}
}
return cache;
}
//......
}
- PostOfficeImpl的route方法在context.isDuplicateDetection()为true时，会调用checkDuplicateID方法，在其返回false时会直接返回RoutingStatus.DUPLICATED_ID；checkDuplicateID方法在bridgeDup为null时会通过message.getDuplicateIDBytes()获取duplicateIDBytes，若不为null则通过getDuplicateIDCache方法从duplicateIDCaches获取DuplicateIDCache，然后判断是否包含该duplicateIDBytes，若为true且rejectDuplicates为true则返回false；而对于cache不为null，且isDuplicate为false的则通过cache.addToCache(duplicateIDBytes, context.getTransaction(), startedTX.get())方法将该duplicateIDBytes添加到cache
handleDuplicateIds
activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/PostOfficeJournalLoader.java
public class PostOfficeJournalLoader implements JournalLoader {
//......
public void handleDuplicateIds(Map<SimpleString, List<Pair<byte[], Long>>> duplicateIDMap) throws Exception {
for (Map.Entry<SimpleString, List<Pair<byte[], Long>>> entry : duplicateIDMap.entrySet()) {
SimpleString address = entry.getKey();
DuplicateIDCache cache = postOffice.getDuplicateIDCache(address);
if (configuration.isPersistIDCache()) {
cache.load(entry.getValue());
}
}
}
//......
}
- PostOfficeJournalLoader的handleDuplicateIds方法在configuration.isPersistIDCache()为true时会执行cache.load(entry.getValue())
DuplicateIDCache
activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/postoffice/DuplicateIDCache.java
public interface DuplicateIDCache {
boolean contains(byte[] duplicateID);
boolean atomicVerify(byte[] duplID, Transaction tx) throws Exception;
void addToCache(byte[] duplicateID) throws Exception;
void addToCache(byte[] duplicateID, Transaction tx) throws Exception;
/**
* it will add the data to the cache.
* If TX == null it won't use a transaction.
* if instantAdd=true, it won't wait a transaction to add on the cache which is needed on the case of the Bridges
*/
void addToCache(byte[] duplicateID, Transaction tx, boolean instantAdd) throws Exception;
void deleteFromCache(byte[] duplicateID) throws Exception;
void load(List<Pair<byte[], Long>> theIds) throws Exception;
void load(Transaction tx, byte[] duplID);
void clear() throws Exception;
List<Pair<byte[], Long>> getMap();
}
- DuplicateIDCache定义了contains、addToCache、load等方法
DuplicateIDCacheImpl
activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/postoffice/impl/DuplicateIDCacheImpl.java
public class DuplicateIDCacheImpl implements DuplicateIDCache {
private static final Logger logger = Logger.getLogger(DuplicateIDCacheImpl.class);
// ByteHolder, position
private final Map<ByteArrayHolder, Integer> cache = new ConcurrentHashMap<>();
private final SimpleString address;
// Note - deliberately typed as ArrayList since we want to ensure fast indexed
// based array access
private final ArrayList<Pair<ByteArrayHolder, Long>> ids;
private int pos;
private final int cacheSize;
private final StorageManager storageManager;
private final boolean persist;
public DuplicateIDCacheImpl(final SimpleString address,
final int size,
final StorageManager storageManager,
final boolean persist) {
this.address = address;
cacheSize = size;
ids = new ArrayList<>(size);
this.storageManager = storageManager;
this.persist = persist;
}
@Override
public void load(final List<Pair<byte[], Long>> theIds) throws Exception {
long txID = -1;
// If we have more IDs than cache size, we shrink the first ones
int deleteCount = theIds.size() - cacheSize;
if (deleteCount < 0) {
deleteCount = 0;
}
for (Pair<byte[], Long> id : theIds) {
if (deleteCount > 0) {
if (txID == -1) {
txID = storageManager.generateID();
}
if (logger.isTraceEnabled()) {
logger.trace("DuplicateIDCacheImpl::load deleting id=" + describeID(id.getA(), id.getB()));
}
storageManager.deleteDuplicateIDTransactional(txID, id.getB());
deleteCount--;
} else {
ByteArrayHolder bah = new ByteArrayHolder(id.getA());
Pair<ByteArrayHolder, Long> pair = new Pair<>(bah, id.getB());
cache.put(bah, ids.size());
ids.add(pair);
if (logger.isTraceEnabled()) {
logger.trace("DuplicateIDCacheImpl::load loading id=" + describeID(id.getA(), id.getB()));
}
}
}
if (txID != -1) {
storageManager.commit(txID);
}
pos = ids.size();
if (pos == cacheSize) {
pos = 0;
}
}
public boolean contains(final byte[] duplID) {
boolean contains = cache.get(new ByteArrayHolder(duplID)) != null;
if (contains) {
logger.trace("DuplicateIDCacheImpl(" + this.address + ")::constains found a duplicate " + describeID(duplID, 0));
}
return contains;
}
public synchronized void addToCache(final byte[] duplID, final Transaction tx, boolean instantAdd) throws Exception {
long recordID = -1;
if (tx == null) {
if (persist) {
recordID = storageManager.generateID();
storageManager.storeDuplicateID(address, duplID, recordID);
}
addToCacheInMemory(duplID, recordID);
} else {
if (persist) {
recordID = storageManager.generateID();
storageManager.storeDuplicateIDTransactional(tx.getID(), address, duplID, recordID);
tx.setContainsPersistent();
}
if (logger.isTraceEnabled()) {
logger.trace("DuplicateIDCacheImpl(" + this.address + ")::addToCache Adding duplicateID TX operation for " + describeID(duplID, recordID) + ", tx=" + tx);
}
if (instantAdd) {
tx.addOperation(new AddDuplicateIDOperation(duplID, recordID, false));
} else {
// For a tx, it's important that the entry is not added to the cache until commit
// since if the client fails then resends them tx we don't want it to get rejected
tx.afterStore(new AddDuplicateIDOperation(duplID, recordID, true));
}
}
}
private synchronized void addToCacheInMemory(final byte[] duplID, final long recordID) {
if (logger.isTraceEnabled()) {
logger.trace("DuplicateIDCacheImpl(" + this.address + ")::addToCacheInMemory Adding " + describeID(duplID, recordID));
}
ByteArrayHolder holder = new ByteArrayHolder(duplID);
cache.put(holder, pos);
Pair<ByteArrayHolder, Long> id;
if (pos < ids.size()) {
// Need fast array style access here -hence ArrayList typing
id = ids.get(pos);
// The id here might be null if it was explicit deleted
if (id.getA() != null) {
if (logger.isTraceEnabled()) {
logger.trace("DuplicateIDCacheImpl(" + this.address + ")::addToCacheInMemory removing excess duplicateDetection " + describeID(id.getA().bytes, id.getB()));
}
cache.remove(id.getA());
// Record already exists - we delete the old one and add the new one
// Note we can't use update since journal update doesn't let older records get
// reclaimed
if (id.getB() != null) {
try {
storageManager.deleteDuplicateID(id.getB());
} catch (Exception e) {
ActiveMQServerLogger.LOGGER.errorDeletingDuplicateCache(e);
}
}
}
id.setA(holder);
// The recordID could be negative if the duplicateCache is configured to not persist,
// -1 would mean null on this case
id.setB(recordID >= 0 ? recordID : null);
if (logger.isTraceEnabled()) {
logger.trace("DuplicateIDCacheImpl(" + this.address + ")::addToCacheInMemory replacing old duplicateID by " + describeID(id.getA().bytes, id.getB()));
}
holder.pos = pos;
} else {
id = new Pair<>(holder, recordID >= 0 ? recordID : null);
if (logger.isTraceEnabled()) {
logger.trace("DuplicateIDCacheImpl(" + this.address + ")::addToCacheInMemory Adding new duplicateID " + describeID(id.getA().bytes, id.getB()));
}
ids.add(id);
holder.pos = pos;
}
if (pos++ == cacheSize - 1) {
pos = 0;
}
}
//......
}
- DuplicateIDCacheImpl实现了DuplicateIDCache接口，其load方法会将数据加载到cache中，其key为ByteArrayHolder类型；其contains方法则根据duplID的byte数组创建ByteArrayHolder，然后从cache中查找是否存在；addToCache方法在tx为null时，则执行addToCacheInMemory，否则往tx添加AddDuplicateIDOperation或者在afterStore时执行AddDuplicateIDOperation；addToCacheInMemory主要是往cache添加记录，同时将cache的大小维护在指定的cacheSize
AddDuplicateIDOperation
activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/postoffice/impl/DuplicateIDCacheImpl.java
private final class AddDuplicateIDOperation extends TransactionOperationAbstract {
final byte[] duplID;
final long recordID;
volatile boolean done;
private final boolean afterCommit;
AddDuplicateIDOperation(final byte[] duplID, final long recordID, boolean afterCommit) {
this.duplID = duplID;
this.recordID = recordID;
this.afterCommit = afterCommit;
}
private void process() {
if (!done) {
addToCacheInMemory(duplID, recordID);
done = true;
}
}
@Override
public void afterCommit(final Transaction tx) {
if (afterCommit) {
process();
}
}
@Override
public void beforeCommit(Transaction tx) throws Exception {
if (!afterCommit) {
process();
}
}
@Override
public List<MessageReference> getRelatedMessageReferences() {
return null;
}
}
- AddDuplicateIDOperation继承了TransactionOperationAbstract；其afterCommit、beforeCommit都会执行process方法，而process方法则是调用addToCacheInMemory(duplID, recordID)
小结
- CoreMessage实现了ICoreMessage接口，而ICoreMessage接口继承了Message接口；它的getDuplicateProperty方法会取Message.HDR_DUPLICATE_DETECTION_ID属性的值
- PostOfficeImpl的route方法在context.isDuplicateDetection()为true时，会调用checkDuplicateID方法，在其返回false时会直接返回RoutingStatus.DUPLICATED_ID；checkDuplicateID方法在bridgeDup为null时会通过message.getDuplicateIDBytes()获取duplicateIDBytes，若不为null则通过getDuplicateIDCache方法从duplicateIDCaches获取DuplicateIDCache，然后判断是否包含该duplicateIDBytes，若为true且rejectDuplicates为true则返回false；而对于cache不为null，且isDuplicate为false的则通过cache.addToCache(duplicateIDBytes, context.getTransaction(), startedTX.get())方法将该duplicateIDBytes添加到cache
- PostOfficeJournalLoader的handleDuplicateIds方法在configuration.isPersistIDCache()为true时会执行cache.load(entry.getValue())
doc
来源：oschina
链接：https://my.oschina.net/go4it/blog/3162127