Generify iterator based on ItemType

src/main/java/edu/uastw/App.java

@@ -34,11 +34,12 @@ public class App {
         library.iterator().forEachRemaining(x -> System.out.println(x.getTitle() + " by " + x.getOwner()));
         printSeparator();
 
-        Iterator<LibraryItem> bookIterator = library.customTypeIterator(Library.ItemType.BOOK);
+        Iterator<LibraryItem> bookIterator = library.customTypeIterator(ItemType.BOOK);
         System.out.println("Books available in the library:");
         bookIterator.forEachRemaining(x -> System.out.println(x.getTitle() + " by " + x.getOwner()));
+        printSeparator();
 
-        Iterator<LibraryItem> magazineIterator = library.customTypeIterator(Library.ItemType.MAGAZINE);
+        Iterator<LibraryItem> magazineIterator = library.customTypeIterator(ItemType.MAGAZINE);
         System.out.println("Magazines available in the library:");
         magazineIterator.forEachRemaining(x -> System.out.println(x.getTitle() + " by " + x.getOwner()));
     }

src/main/java/edu/uastw/Book.java

@@ -9,6 +9,7 @@ public class Book implements LibraryItem {
         this.author = author;
     }
 
+    @Override
     public String getTitle() {
         return title;
     }
@@ -17,4 +18,9 @@ public class Book implements LibraryItem {
     public String getOwner() {
         return author;
     }
+
+    @Override
+    public ItemType getType() {
+        return ItemType.BOOK;
+    }
 }

src/main/java/edu/uastw/ItemType.java

@@ -0,0 +1,6 @@
+package edu.uastw;
+
+public enum ItemType {
+    BOOK,
+    MAGAZINE
+}

src/main/java/edu/uastw/Library.java

@@ -19,6 +19,7 @@ public class Library implements Iterable<LibraryItem> {
         }
         return instance;
     }
+
     public void setBooksCapacity(int capacity) {
         this.booksCapacity = capacity;
     }
@@ -62,16 +63,10 @@ public class Library implements Iterable<LibraryItem> {
         }
     }
 
-    public enum ItemType {
-        BOOK,
-        MAGAZINE
-    }
-
     public Iterator<LibraryItem> customTypeIterator(ItemType type) {
         List<LibraryItem> itemsOfType = new ArrayList<>();
         for (LibraryItem item : libraryItems) {
-            if ((type == ItemType.BOOK && item instanceof Book) ||
-                    (type == ItemType.MAGAZINE && item instanceof Magazine)) {
+            if (item.getType() == type) {
                 itemsOfType.add(item);
             }
         }

src/main/java/edu/uastw/LibraryItem.java

@@ -3,4 +3,5 @@ package edu.uastw;
 public interface LibraryItem {
     String getTitle();
     String getOwner();
+    ItemType getType();
 }

src/main/java/edu/uastw/Magazine.java

@@ -9,6 +9,7 @@ public class Magazine implements LibraryItem {
         this.publisher = publisher;
     }
 
+    @Override
     public String getTitle() {
         return title;
     }
@@ -17,4 +18,9 @@ public class Magazine implements LibraryItem {
     public String getOwner() {
         return publisher;
     }
+
+    @Override
+    public ItemType getType() {
+        return ItemType.MAGAZINE;
+    }
 }