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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.example.http.websocketx.server;
17  
18  import java.util.Locale;
19  
20  import io.netty.channel.ChannelHandlerContext;
21  import io.netty.channel.SimpleChannelInboundHandler;
22  import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
23  import io.netty.handler.codec.http.websocketx.WebSocketFrame;
24  
25  /**
26   * Echoes uppercase content of text frames.
27   */
28  public class WebSocketFrameHandler extends SimpleChannelInboundHandler<WebSocketFrame> {
29  
30      @Override
31      protected void channelRead0(ChannelHandlerContext ctx, WebSocketFrame frame) throws Exception {
32          // ping and pong frames already handled
33  
34          if (frame instanceof TextWebSocketFrame) {
35              // Send the uppercase string back.
36              String request = ((TextWebSocketFrame) frame).text();
37              ctx.channel().writeAndFlush(new TextWebSocketFrame(request.toUpperCase(Locale.US)));
38          } else {
39              String message = "unsupported frame type: " + frame.getClass().getName();
40              throw new UnsupportedOperationException(message);
41          }
42      }
43  }