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1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.handler.codec.http.websocketx;
17  
18  import io.netty.util.AsciiString;
19  import io.netty.util.internal.StringUtil;
20  
21  /**
22   * <p>
23   * Versions of the web socket specification.
24   * </p>
25   * <p>
26   * A specification is tied to one wire protocol version but a protocol version may have use by more than 1 version of
27   * the specification.
28   * </p>
29   */
30  public enum WebSocketVersion {
31      UNKNOWN(AsciiString.cached(StringUtil.EMPTY_STRING)),
32  
33      /**
34       * <a href= "http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-00"
35       * >draft-ietf-hybi-thewebsocketprotocol- 00</a>.
36       */
37      V00(AsciiString.cached("0")),
38  
39      /**
40       * <a href= "http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-07"
41       * >draft-ietf-hybi-thewebsocketprotocol- 07</a>
42       */
43      V07(AsciiString.cached("7")),
44  
45      /**
46       * <a href= "http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-10"
47       * >draft-ietf-hybi-thewebsocketprotocol- 10</a>
48       */
49      V08(AsciiString.cached("8")),
50  
51      /**
52       * <a href="http://tools.ietf.org/html/rfc6455 ">RFC 6455</a>. This was originally <a href=
53       * "http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-17" >draft-ietf-hybi-thewebsocketprotocol-
54       * 17</a>
55       */
56      V13(AsciiString.cached("13"));
57  
58      private final AsciiString headerValue;
59  
60      WebSocketVersion(AsciiString headerValue) {
61          this.headerValue = headerValue;
62      }
63      /**
64       * @return Value for HTTP Header 'Sec-WebSocket-Version'
65       */
66      public String toHttpHeaderValue() {
67          return toAsciiString().toString();
68      }
69  
70      AsciiString toAsciiString() {
71          if (this == UNKNOWN) {
72              // Let's special case this to preserve behaviour
73              throw new IllegalStateException("Unknown web socket version: " + this);
74          }
75          return headerValue;
76      }
77  }