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1   /*
2    * Copyright 2019 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    *   https://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.extensions;
17  
18  import io.netty.handler.codec.http.websocketx.WebSocketFrame;
19  
20  /**
21   * Filter that is responsible to skip the evaluation of a certain extension
22   * according to standard.
23   */
24  public interface WebSocketExtensionFilter {
25  
26      /**
27       * A {@link WebSocketExtensionFilter} that never skip the evaluation of an
28       * any given extensions {@link WebSocketExtension}.
29       */
30      WebSocketExtensionFilter NEVER_SKIP = new WebSocketExtensionFilter() {
31          @Override
32          public boolean mustSkip(WebSocketFrame frame) {
33              return false;
34          }
35      };
36  
37      /**
38       * A {@link WebSocketExtensionFilter} that always skip the evaluation of an
39       * any given extensions {@link WebSocketExtension}.
40       */
41      WebSocketExtensionFilter ALWAYS_SKIP = new WebSocketExtensionFilter() {
42          @Override
43          public boolean mustSkip(WebSocketFrame frame) {
44              return true;
45          }
46      };
47  
48      /**
49       * Returns {@code true} if the evaluation of the extension must skipped
50       * for the given frame otherwise {@code false}.
51       */
52      boolean mustSkip(WebSocketFrame frame);
53  
54  }