Implement more iterators and refactor

test/pom.xml

@@ -14,4 +14,16 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>3.0.0</version>
+                <configuration>
+                    <mainClass>edu.uastw.App</mainClass>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 </project>

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

@@ -1,6 +1,8 @@
 package edu.uastw;
 
-public class Test {
+import java.util.Iterator;
+
+public class App {
     public static void main(String[] args) {
         LibraryItem book1 = new Book("The Great Gatsby", "F. Scott Fitzgerald");
         LibraryItem book2 = new Book("To Kill a Mockingbird", "Harper Lee");
@@ -8,6 +10,7 @@ public class Test {
         LibraryItem magazine1 = new Magazine("National Geographic", "National Geographic Society");
 
         Library library = new LibraryBuilder()
+                .setBooksCapacity(3)
                 .addLibraryItem(book1)
                 .addLibraryItem(book2)
                 .addLibraryItem(book3)
@@ -15,22 +18,32 @@ public class Test {
                 .build();
 
         library.displayLibraryItems();
+        printSeparator();
 
         LibraryDecorator increasedCapacityLibrary = new IncreaseBooksCapacityDecorator(library, 1);
         increasedCapacityLibrary.extendedFunctionality();
 
         library.addLibraryItem(magazine1);
         library.displayLibraryItems();
-
-        System.out.println("Modified books capacity: " + library.getBooksCapacity());
+        printSeparator();
 
         LibraryDecorator decreasedCapacityLibrary = new DecreaseBooksCapacityDecorator(library, 2);
         decreasedCapacityLibrary.extendedFunctionality();
 
-        System.out.println("Modified books capacity: " + library.getBooksCapacity());
-        library.displayLibraryItems();
-
         library.addLibraryItem(magazine1);
-        library.displayLibraryItems();
+        library.iterator().forEachRemaining(x -> System.out.println(x.getTitle() + " by " + x.getOwner()));
+        printSeparator();
+
+        Iterator<LibraryItem> bookIterator = library.customTypeIterator(Library.ItemType.BOOK);
+        System.out.println("Books available in the library:");
+        bookIterator.forEachRemaining(x -> System.out.println(x.getTitle() + " by " + x.getOwner()));
+
+        Iterator<LibraryItem> magazineIterator = library.customTypeIterator(Library.ItemType.MAGAZINE);
+        System.out.println("Magazines available in the library:");
+        magazineIterator.forEachRemaining(x -> System.out.println(x.getTitle() + " by " + x.getOwner()));
+    }
+
+    private static void printSeparator() {
+        System.out.println("-------------------");
     }
 }

test/src/main/java/edu/uastw/DecreaseBooksCapacityDecorator.java

@@ -1,6 +1,6 @@
 package edu.uastw;
 
-class DecreaseBooksCapacityDecorator extends LibraryDecorator {
+public class DecreaseBooksCapacityDecorator extends LibraryDecorator {
     private final int reducedCapacity;
 
     public DecreaseBooksCapacityDecorator(Library library, int reducedCapacity) {

test/src/main/java/edu/uastw/IncreaseBooksCapacityDecorator.java

@@ -1,6 +1,6 @@
 package edu.uastw;
 
-class IncreaseBooksCapacityDecorator extends LibraryDecorator {
+public class IncreaseBooksCapacityDecorator extends LibraryDecorator {
     private final int additionalCapacity;
 
     public IncreaseBooksCapacityDecorator(Library library, int additionalCapacity) {

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

@@ -1,9 +1,10 @@
 package edu.uastw;
 
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
 
-public class Library {
+public class Library implements Iterable<LibraryItem> {
     private static Library instance;
     private final List<LibraryItem> libraryItems;
     private int booksCapacity = 3;
@@ -29,6 +30,7 @@ public class Library {
     public void addLibraryItem(LibraryItem libraryItem) {
         if (libraryItems.size() < booksCapacity) {
             libraryItems.add(libraryItem);
+            System.out.println("'" + libraryItem.getTitle() + "' was added.");
         } else {
             System.out.println("Library capacity reached. Cannot add more items.");
         }
@@ -40,4 +42,39 @@ public class Library {
                 System.out.println(libraryItem.getTitle() + " by " + libraryItem.getOwner())
         );
     }
+
+    @Override
+    public Iterator<LibraryItem> iterator() {
+        return new LibraryItemIterator();
+    }
+
+    private class LibraryItemIterator implements Iterator<LibraryItem> {
+        private int currentIndex = 0;
+
+        @Override
+        public boolean hasNext() {
+            return currentIndex < booksCapacity;
+        }
+
+        @Override
+        public LibraryItem next() {
+            return libraryItems.get(currentIndex++);
+        }
+    }
+
+    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)) {
+                itemsOfType.add(item);
+            }
+        }
+        return itemsOfType.iterator();
+    }
 }

test/src/main/java/edu/uastw/LibraryBuilder.java

@@ -12,6 +12,11 @@ public class LibraryBuilder {
         return this;
     }
 
+    public LibraryBuilder setBooksCapacity(int booksCapacity) {
+        library.setBooksCapacity(booksCapacity);
+        return this;
+    }
+
     public Library build() {
         return library;
     }

test/src/main/java/edu/uastw/LibraryDecorator.java

@@ -1,6 +1,6 @@
 package edu.uastw;
 
-abstract class LibraryDecorator extends Library {
+public abstract class LibraryDecorator extends Library {
     protected Library library;
 
     public LibraryDecorator(Library library) {

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

@@ -1,6 +1,6 @@
 package edu.uastw;
 
-interface LibraryItem {
+public interface LibraryItem {
     String getTitle();
     String getOwner();
 }