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/*
* Copyright 2014 The Netty Project
*
* The Netty Project 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:
*
* https://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 net.dreamlu.iot.mqtt.codec;
/**
* Mqtt QoS
*
* @author netty
*/
public enum MqttQoS {
/**
* QoS level 0 至多发送一次，发送即丢弃。没有确认消息，也不知道对方是否收到。
*/
QOS0(0),
/**
* QoS level 1 至少一次，都要在可变头部中附加一个16位的消息ID，SUBSCRIBE 和 UNSUBSCRIBE 消息使用 QoS level 1。
*/
QOS1(1),
/**
* QoS level 2 确保只有一次，仅仅在 PUBLISH 类型消息中出现，要求在可变头部中要附加消息ID。
*/
QOS2(2),
/**
* 失败
*/
FAILURE(0x80);
private final int value;
MqttQoS(int value) {
this.value = value;
}
public int value() {
return value;
}
public static MqttQoS valueOf(int value) {
switch (value) {
case 0:
return QOS0;
case 1:
return QOS1;
case 2:
return QOS2;
case 0x80:
return FAILURE;
default:
throw new IllegalArgumentException("invalid QoS: " + value);
}
}
@Override
public String toString() {
return "QoS" + value;
}
}