src/charactermanaj/graphics/io/ImageCachedLoader.java

   1 package charactermanaj.graphics.io;\r
   2 \r
   3 import java.io.Closeable;\r
   4 import java.io.IOException;\r
   5 \r
   6 \r
   7 /**\r
   8  * 一度読み込んだ画像をキャッシュする画像ローダ.<br>\r
   9  * すでに読み込まれており、ファイルの更新日に変更がなければ読み込み済みの画像をかえす.<br>\r
  10  * @author seraphy\r
  11  */\r
  12 public class ImageCachedLoader extends ImageLoaderImpl implements Closeable {\r
  13 \r
  14         /**\r
  15          * リソースに対するイメージキャッシュ.<br>\r
  16          * リソースは複数のプロファイルで共有しえるのでstaticとしている。\r
  17          */\r
  18         private static ImageCache<ImageResourceCacheKey> caches = new ImageCache<ImageResourceCacheKey>();\r
  19 \r
  20         @Override\r
  21     public LoadedImage load(ImageResource imageResource) throws IOException {\r
  22                 if (imageResource == null) {\r
  23                         throw new IllegalArgumentException();\r
  24                 }\r
  25 \r
  26                 ImageResourceCacheKey key = new ImageResourceCacheKey(imageResource);\r
  27 \r
  28                 synchronized (caches) {\r
  29                         LoadedImage loadedImage = caches.get(key);\r
  30 \r
  31                         if (loadedImage != null) {\r
  32                                 long lastModified = loadedImage.getLastModified();\r
  33                                 if (lastModified != imageResource.lastModified()) {\r
  34                                         // キャッシュされているが、すでに古い場合は破棄する.\r
  35                                         loadedImage = null;\r
  36                                 }\r
  37                         }\r
  38 \r
  39                         if (loadedImage == null) {\r
  40                                 loadedImage = super.load(imageResource);\r
  41                                 caches.set(key, loadedImage);\r
  42                                 caches.unlockImages(); // 即時解放許可\r
  43                         }\r
  44 \r
  45                         return loadedImage;\r
  46                 }\r
  47         }\r
  48 \r
  49         public void close() {\r
  50             caches.clear();\r
  51         }\r
  52 }\r
  53 \r
  54 final class ImageResourceCacheKey {\r
  55 \r
  56         private final ImageResource imageResource;\r
  57 \r
  58         private final int hashCode;\r
  59 \r
  60         public ImageResourceCacheKey(ImageResource imageResource) {\r
  61                 if (imageResource == null) {\r
  62                         throw new IllegalArgumentException();\r
  63                 }\r
  64                 this.imageResource = imageResource;\r
  65                 this.hashCode = imageResource.hashCode();\r
  66         }\r
  67 \r
  68         @Override\r
  69         public int hashCode() {\r
  70                 return this.hashCode;\r
  71         }\r
  72 \r
  73         @Override\r
  74         public boolean equals(Object obj) {\r
  75                 if (obj == this) {\r
  76                         return true;\r
  77                 }\r
  78                 if (obj != null && obj instanceof ImageResourceCacheKey) {\r
  79                         ImageResourceCacheKey other = (ImageResourceCacheKey) obj;\r
  80                         return imageResource.equals(other.imageResource);\r
  81                 }\r
  82                 return false;\r
  83         }\r
  84 }\r