first commit

Semester 1/Programming 1/Java/examples/projects/chapter13/musicplayer/TrackReader.java

@@ -0,0 +1,91 @@
+import java.io.File;
+import java.io.FilenameFilter;
+import java.io.IOException;
+import java.util.ArrayList;
+
+/**
+ * A helper class for our music application. This class can read files from the file system
+ * from a given folder with a specified suffix. It will interpret the file name as artist/
+ * track title information.
+ * 
+ * It is expected that file names of music tracks follow a standard format of artist name
+ * and track name, separated by a dash. For example: TheBeatles-HereComesTheSun.mp3
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class TrackReader
+{
+    /**
+     * Create the track reader, ready to read tracks from the music library folder.
+     */
+    public TrackReader()
+    {
+        // Nothing to do here.
+    }
+    
+    /**
+     * Read music files from the given library folder
+     * with the given suffix.
+     * @param folder The folder to look for files.
+     * @param suffix The suffix of the audio type.
+     */
+    public ArrayList<Track> readTracks(String folder, final String suffix)
+    {
+        File audioFolder = new File(folder);
+        ArrayList<Track> tracks = new ArrayList<>();
+        File[] audioFiles = audioFolder.listFiles(new FilenameFilter() {
+            /**
+             * Accept files with matching suffix.
+             * @param dir The directory containing the file.
+             * @param name The name of the file.
+             * @return true if the name ends with the suffix.
+             */
+            public boolean accept(File dir, String name)
+            {
+                return name.toLowerCase().endsWith(suffix);
+            }
+        });
+        
+        // Put all the matching files into the organizer.
+        for(File file : audioFiles) {
+            Track trackDetails = decodeDetails(file);
+            tracks.add(trackDetails);
+        }
+        return tracks;
+    }
+
+    /**
+     * Try to decode details of the artist and the title
+     * from the file name.
+     * It is assumed that the details are in the form:
+     *     artist-title.mp3
+     * @param file The track file.
+     * @return A Track containing the details.
+     */
+    private Track decodeDetails(File file)
+    {
+        // The information needed.
+        String artist = "unknown";
+        String title = "unknown";
+        String filename = file.getPath();
+        
+        // Look for artist and title in the name of the file.
+        String details = file.getName();
+        String[] parts = details.split("-");
+        
+        if(parts.length == 2) {
+            artist = parts[0];
+            String titlePart = parts[1];
+            // Remove a file-type suffix.
+            parts = titlePart.split("\\.");
+            if(parts.length >= 1) {
+                title = parts[0];
+            }
+            else {
+                title = titlePart;
+            }
+        }
+        return new Track(artist, title, filename);
+    }
+}