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<MessageReference> 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() : "")
});
}
}
@Override
public synchronized void destroy() throws Exception {
stop();
for (Iterator<MessageReference> i = memoryList.iterator(); i.hasNext(); ) {
MessageReference node = i.next();
node.decrementReferenceCount();
}
memoryList.clear();
destroyDiskList();
}
protected synchronized void expireOldMessages() {
if (!memoryList.isEmpty()) {
for (Iterator<MessageReference> iterator = memoryList.iterator(); iterator.hasNext(); ) {
MessageReference node = iterator.next();
if (node.isExpired()) {
node.decrementReferenceCount();
discardExpiredMessage(node);
iterator.remove();
}
}
}
}
/** @return true if there are no pending messages */
@Override
public synchronized boolean isEmpty() {
if (memoryList.isEmpty() && isDiskListEmpty()) {
return true;
}
for (Iterator<MessageReference> 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();
}
@Override
public synchronized LinkedList<MessageReference> pageInList(int maxItems) {
LinkedList<MessageReference> result = new LinkedList<MessageReference>();
int count = 0;
for (Iterator<MessageReference> i = memoryList.iterator(); i.hasNext() && count < maxItems; ) {
MessageReference ref = i.next();
ref.incrementReferenceCount();
result.add(ref);
count++;
}
if (count < maxItems && !isDiskListEmpty()) {
for (Iterator<MessageReference> 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;
}