added ImageStorage to precache images to remove IO bottleneck

cicaprojekt/ImageStorage.java

@@ -0,0 +1,31 @@
+package cicaprojekt;
+
+import javax.imageio.ImageIO;
+import javax.swing.filechooser.FileNameExtensionFilter;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+
+public class ImageStorage {
+    private Map<String, BufferedImage> images;
+
+    public ImageStorage() throws IOException {
+        images = new HashMap<>();
+
+        File dir = new File(System.getProperty("user.dir"));
+        FileNameExtensionFilter filter = new FileNameExtensionFilter("N/A", "png");
+
+        for (File f : dir.listFiles()) {
+            if (filter.accept(f) && f.isFile()){
+                images.put(f.getName(), ImageIO.read(f));
+            }
+        }
+    }
+
+    public BufferedImage getImage(String filename) {
+        return images.get(filename);
+    }
+}