task 2

src/ch/hevs/isc/slopify_v2/Album.scala

@@ -2,8 +2,11 @@ package ch.hevs.isc.slopify_v2
 
 import scala.collection.mutable.ArrayBuffer
 
-class Album(val name: String) {
-  private var songs: ArrayBuffer[Song] = new ArrayBuffer()
-  def addSong(song: Song): Unit = songs.addOne(song)
-  def containsSong(song: Song): Boolean = songs.contains(song)
+class Album(val name: String) extends Serializable {
+  private var _songs: ArrayBuffer[Song] = new ArrayBuffer()
+  def addSong(song: Song): Unit = _songs.addOne(song)
+  def containsSong(song: Song): Boolean = _songs.contains(song)
+  def getSongs(): Array[Song] = _songs.toArray
+
+  override def toString: String = s"<Album '$name': ${_songs.length} song(s)>"
 }

src/ch/hevs/isc/slopify_v2/Artist.scala

@@ -2,9 +2,12 @@ package ch.hevs.isc.slopify_v2
 
 import scala.collection.mutable.ArrayBuffer
 
-class Artist(val name: String) {
-  private var albums: ArrayBuffer[Album] = new ArrayBuffer()
-  def addAlbum(album: Album): Unit = albums.addOne(album)
+class Artist(val name: String) extends Serializable {
+  private var _albums: ArrayBuffer[Album] = new ArrayBuffer()
+  def addAlbum(album: Album): Unit = _albums.addOne(album)
 
-  def hasAlbum(album: Album): Boolean = albums.contains(album)
+  def hasAlbum(album: Album): Boolean = _albums.contains(album)
+  def getAlbums(): Array[Album] = _albums.toArray
+
+  override def toString: String = s"<Artist '$name': ${_albums.length} album(s)>"
 }

src/ch/hevs/isc/slopify_v2/DataBase.scala

@@ -2,8 +2,11 @@ package ch.hevs.isc.slopify_v2
 
 import scala.collection.mutable.ArrayBuffer
 
-class DataBase {
-  private var artists: ArrayBuffer[Artist] = new ArrayBuffer()
-  def addArtist(artist: Artist): Unit = artists.addOne(artist)
-  def containsArtist(artist: Artist): Boolean = artists.contains(artist)
+class DataBase extends Serializable {
+  private var _artists: ArrayBuffer[Artist] = new ArrayBuffer()
+  def addArtist(artist: Artist): Unit = _artists.addOne(artist)
+  def containsArtist(artist: Artist): Boolean = _artists.contains(artist)
+  def getArtists(): Array[Artist] = _artists.toArray
+
+  override def toString: String = s"<Database: ${_artists.length} artist(s)>"
 }

src/ch/hevs/isc/slopify_v2/DataBaseHelper.scala

@@ -1,6 +1,6 @@
 package ch.hevs.isc.slopify_v2
 
-import java.io.File
+import java.io.{File, FileInputStream, FileOutputStream, ObjectInput, ObjectInputStream, ObjectOutputStream}
 
 object DataBaseHelper {
   def create(directory:String) : DataBase = {
@@ -52,11 +52,30 @@ object DataBaseHelper {
     return db
   }
 
-  def save(fileName:String, db:DataBase) : Unit = ???
-  def load(fileName:String) : DataBase = ???
+  def save(fileName: String, db: DataBase) : Unit = {
+    val fos: FileOutputStream = new FileOutputStream(fileName)
+    val oos: ObjectOutputStream = new ObjectOutputStream(fos)
+    oos.writeObject(db)
+    oos.close()
+  }
+  def load(fileName:String) : DataBase = {
+    val fis: FileInputStream = new FileInputStream(fileName)
+    val ois: ObjectInputStream = new ObjectInputStream(fis)
+    val db: DataBase = ois.readObject().asInstanceOf[DataBase]
+    ois.close()
+    return db
+  }
 
   def main(args: Array[String]): Unit = {
     val db: DataBase = create("res/songs")
+    println(db)
+    val artists: Array[Artist] = db.getArtists()
+    println(artists(0))
 
+    save("res/db.bin", db)
+    val db2: DataBase = load("res/db.bin")
+    println(db2)
+    val artists2: Array[Artist] = db2.getArtists()
+    println(artists2(0))
   }
 }

src/ch/hevs/isc/slopify_v2/Song.scala

@@ -1,5 +1,5 @@
 package ch.hevs.isc.slopify_v2
 
-class Song(val title: String, val number: Int) {
-
+class Song(val title: String, val number: Int) extends Serializable {
+  override def toString: String = s"<Song n° $number '$title'>"
 }