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fix bug: Under high concurrency, Mqtt client nextMessageId exceeds the 0xffff limit (#2564)

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The compareAndSet method and getAndIncrement method of the AtomicInteger class are atomic, but when these two methods are used at the same time, they are no longer atomic.
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blackstar-baba 2020-04-01 14:39:51 +08:00 committed by GitHub
parent d94cb9ca47
commit 00b5d36e0b
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1 changed files with 6 additions and 2 deletions
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netty-mqtt/src/main/java/org/thingsboard/mqtt/MqttClientImpl.java
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@ -407,8 +407,12 @@ final class MqttClientImpl implements MqttClient {
}
private MqttMessageIdVariableHeader getNewMessageId() {
this.nextMessageId.compareAndSet(0xffff, 1);
return MqttMessageIdVariableHeader.from(this.nextMessageId.getAndIncrement());
int messageId;
synchronized (this.nextMessageId) {
this.nextMessageId.compareAndSet(0xffff, 1);
messageId = this.nextMessageId.getAndIncrement();
}
return MqttMessageIdVariableHeader.from(messageId);
}
private Future<Void> createSubscription(String topic, MqttHandler handler, boolean once, MqttQoS qos) {