From b9517d995a4b0510a8111392f1b0b612eac58de0 Mon Sep 17 00:00:00 2001
From: Nathan Cannon <neviynhd@gmail.com>
Date: Tue, 28 Mar 2017 02:53:38 +0100
Subject: [PATCH] Album art is now cached so reuse of album art in UI elements
 doesn't always need to reload image from disc.

---
 pom.xml                                    |  5 ++++
 src/main/java/musicplayer/model/Album.java | 32 ++++++++++++++++++++--
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/pom.xml b/pom.xml
index 1aca807..abf4e16 100644
--- a/pom.xml
+++ b/pom.xml
@@ -139,6 +139,11 @@
             <version>1.6.5-1</version>
             <scope>compile</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>21.0</version>
+        </dependency>
         <dependency>
             <groupId>org.apache.logging.log4j</groupId>
             <artifactId>log4j-core</artifactId>
diff --git a/src/main/java/musicplayer/model/Album.java b/src/main/java/musicplayer/model/Album.java
index 290ab60..3ddfcdc 100644
--- a/src/main/java/musicplayer/model/Album.java
+++ b/src/main/java/musicplayer/model/Album.java
@@ -1,5 +1,8 @@
 package musicplayer.model;
 
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
 import org.jaudiotagger.audio.AudioFileIO;
 import org.jaudiotagger.audio.exceptions.CannotReadException;
 import org.jaudiotagger.audio.exceptions.InvalidAudioFrameException;
@@ -19,6 +22,7 @@ import java.nio.file.Path;
 import java.util.NoSuchElementException;
 import java.util.Optional;
 import java.util.Set;
+import java.util.concurrent.ExecutionException;
 
 /**
  * Representation of an Album.
@@ -41,6 +45,17 @@ public class Album implements Comparable<Album>, IDBType, HasSongs {
     private static final String albumArtRegex = "*{Cover,Folder,cover,folder}\\.{jpg,png}";
     @Transient
     private static final int imageScaleToSize = 50;
+    @Transient
+    private static final LoadingCache<Album, Optional<ImageIcon>> albumArtCache = CacheBuilder.newBuilder()
+            .maximumSize(1000)
+            .build(
+                    new CacheLoader<Album, Optional<ImageIcon>>() {
+                        @Override
+                        public Optional<ImageIcon> load(Album album) throws Exception {
+                            return getAlbumArt(album);
+                        }
+                    }
+            );
 
     protected Album() {
     }
@@ -100,13 +115,26 @@ public class Album implements Comparable<Album>, IDBType, HasSongs {
     }
 
     /**
-     * Get album art for a given album.
+     * Get album art for this given album.
      * @return Album art.
      */
     @Transient
     public Optional<ImageIcon> getAlbumArt(){
+        try {
+            return albumArtCache.get(this);
+        } catch (ExecutionException ignored) {}
+        return Optional.empty();
+    }
+
+    /**
+     * Get album are for a given album.
+     * @param album Album to get art for.
+     * @return Album art.
+     */
+    @Transient
+    private static Optional<ImageIcon> getAlbumArt(Album album){
         Tag audioTags;
-        File targetFile = songs.iterator().next().getSongFile();
+        File targetFile = album.songs.iterator().next().getSongFile();
         Path baseDir = targetFile.getParentFile().toPath();
         try {
             audioTags = AudioFileIO.read(targetFile).getTag();