[ROCKETMQ-22] new funciton 'printWaterMark' in version 3.5.8(4.0.0) will cause a ClassCastException

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 4.0.0-incubating
• Fix Version/s: 4.0.0-incubating
• Component/s: rocketmq-broker
• Assignee: Xinyu Zhou
• Reporter: libin
• Created: 28/Dec/16 02:19
• Updated: 23/Jan/17 09:25
• Resolved: 09/Jan/17 14:02

Description

ew funciton 'printWaterMark' in version 3.5.8(4.0.0) will cause a ClassCastException;

printWaterMark.headSlowTimeMills4PullThreadPoolQueue.headSlowTimeMills

public long headSlowTimeMills(BlockingQueue<Runnable> q) {
long slowTimeMills = 0;
final Runnable peek = q.peek();
if (peek != null) {

RequestTask rt = BrokerFastFailure.castRunnable(peek);

slowTimeMills = this.messageStore.now() - rt.getCreateTimestamp();
}

if (slowTimeMills < 0) slowTimeMills = 0;

return slowTimeMills;
}

in BrokerFastFailure.castRunnable, it will cast runnable to RequestTask

public static RequestTask castRunnable(final Runnable runnable) {
try {
FutureTaskExt object = (FutureTaskExt) runnable;

return (RequestTask) object.getRunnable();
...
}

return null;
}

but in a specail condition, it don't submit a RequestTask, so cause a ClassCastException

this.brokerController.getPullMessageProcessor().excuteRequestWhenWakeup(request.getClientChannel(), request.getRequestCommand());

public void excuteRequestWhenWakeup(final Channel channel, final RemotingCommand request) throws RemotingCommandException {

Runnable run = new Runnable() {

@Override
public void run() {
try {
final RemotingCommand response = PullMessageProcessor.this.processRequest(channel, request, false);
....

this.brokerController.getPullMessageExecutor().submit(run);

}