From f211d004009e4a4755d394d44c3409520440bd9d Mon Sep 17 00:00:00 2001
From: orange <raffy.m.96@gmail.com>
Date: Fri, 30 Dec 2016 14:57:37 +0100
Subject: [PATCH] add abstract class

---
 src/Museo/Archivio.java | 7 +------
 src/Museo/Opera.java    | 6 +++++-
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/Museo/Archivio.java b/src/Museo/Archivio.java
index a732cbe..a5d95d6 100644
--- a/src/Museo/Archivio.java
+++ b/src/Museo/Archivio.java
@@ -33,12 +33,7 @@ public class Archivio{
 
     public void print(PrintStream ps){
         for(Opera o: archivio){
-            if(o instanceof Libro)
-                ((Libro) o).print(ps);
-            if(o instanceof Stampa)
-                ((Stampa) o).print(ps);
-            if(o instanceof OperaMult)
-                ((OperaMult) o).print(ps);
+            o.print(ps);
         }
     }
 
diff --git a/src/Museo/Opera.java b/src/Museo/Opera.java
index b2668e6..8c1e6a7 100644
--- a/src/Museo/Opera.java
+++ b/src/Museo/Opera.java
@@ -1,4 +1,6 @@
-public class Opera{
+import java.io.PrintStream;
+
+abstract public class Opera{
     public Opera(String autore, String titolo, int anno, String pos){
         this.anno=anno;
         this.autore=autore;
@@ -26,6 +28,8 @@ public class Opera{
         return autore.hashCode()*titolo.hashCode()*pos.hashCode()*anno;
     }
 
+    abstract public void print(PrintStream ps);
+
     protected int anno;
     protected String autore;
     protected String titolo;