Java example source code file (MqttVersion.java)

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Java - Java tags/keywords

mqisdp, mqtt_3_1_1, mqttunacceptableprotocolversionexception, mqttversion, string

The MqttVersion.java Java example source code

/*
 * 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:
 *
 *   http://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 io.netty.handler.codec.mqtt;

import io.netty.util.CharsetUtil;
import io.netty.util.internal.ObjectUtil;

/**
 * Mqtt version specific constant values used by multiple classes in mqtt-codec.
 */
public enum MqttVersion {
    MQTT_3_1("MQIsdp", (byte) 3),
    MQTT_3_1_1("MQTT", (byte) 4);

    private final String name;
    private final byte level;

    MqttVersion(String protocolName, byte protocolLevel) {
        name = ObjectUtil.checkNotNull(protocolName, "protocolName");
        level = protocolLevel;
    }

    public String protocolName() {
        return name;
    }

    public byte[] protocolNameBytes() {
        return name.getBytes(CharsetUtil.UTF_8);
    }

    public byte protocolLevel() {
        return level;
    }

    public static MqttVersion fromProtocolNameAndLevel(String protocolName, byte protocolLevel) {
        for (MqttVersion mv : values()) {
            if (mv.name.equals(protocolName)) {
                if (mv.level == protocolLevel) {
                    return mv;
                } else {
                    throw new MqttUnacceptableProtocolVersionException(protocolName + " and " +
                            protocolLevel + " are not match");
                }
            }
        }
        throw new MqttUnacceptableProtocolVersionException(protocolName + "is unknown protocol name");
    }
}