查看本类的 API文档回源码主页

   /*
    * 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 io.netty.handler.codec.haproxy;
  
  import static io.netty.handler.codec.haproxy.HAProxyConstants.*;
  
  /**
   * The HAProxy proxy protocol specification version.
   */
  public enum HAProxyProtocolVersion {
      /**
       * The ONE proxy protocol version represents a version 1 (human-readable) header.
       */
      V1(VERSION_ONE_BYTE),
      /**
       * The TWO proxy protocol version represents a version 2 (binary) header.
       */
      V2(VERSION_TWO_BYTE);
  
      /**
       * The highest 4 bits of the protocol version and command byte contain the version
       */
      private static final byte VERSION_MASK = (byte) 0xf0;
  
      private final byte byteValue;
  
      /**
       * Creates a new instance
       */
      HAProxyProtocolVersion(byte byteValue) {
          this.byteValue = byteValue;
      }
  
      /**
       * Returns the {@link HAProxyProtocolVersion} represented by the highest 4 bits of the specified byte.
       *
       * @param verCmdByte protocol version and command byte
       */
      public static HAProxyProtocolVersion valueOf(byte verCmdByte) {
          int version = verCmdByte & VERSION_MASK;
          switch ((byte) version) {
              case VERSION_TWO_BYTE:
                  return V2;
              case VERSION_ONE_BYTE:
                  return V1;
              default:
                  throw new IllegalArgumentException("unknown version: " + version);
          }
      }
  
      /**
       * Returns the byte value of this version.
       */
      public byte byteValue() {
          return byteValue;
      }
  }