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1   /*
2    * Copyright 2015 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  
17  package io.netty.example.http2.tiles;
18  
19  import static io.netty.buffer.Unpooled.unreleasableBuffer;
20  import static io.netty.example.http2.Http2ExampleUtil.toByteBuf;
21  import io.netty.buffer.ByteBuf;
22  
23  import java.io.IOException;
24  import java.util.HashMap;
25  import java.util.Map;
26  
27  /**
28   * Caches the images to avoid reading them every time from the disk.
29   */
30  public final class ImageCache {
31  
32      public static ImageCache INSTANCE = new ImageCache();
33  
34      private final Map<String, ByteBuf> imageBank = new HashMap<String, ByteBuf>(200);
35  
36      private ImageCache() {
37          init();
38      }
39  
40      public static String name(int x, int y) {
41          return "tile-" + y + "-" + x + ".jpeg";
42      }
43  
44      public ByteBuf image(int x, int y) {
45          return imageBank.get(name(x, y));
46      }
47  
48      private void init() {
49          for (int y = 0; y < 10; y++) {
50              for (int x = 0; x < 20; x++) {
51                  try {
52                      String name = name(x, y);
53                      ByteBuf fileBytes = unreleasableBuffer(toByteBuf(getClass()
54                              .getResourceAsStream(name)).asReadOnly());
55                      imageBank.put(name, fileBytes);
56                  } catch (IOException e) {
57                      e.printStackTrace();
58                  }
59              }
60          }
61      }
62  }