public class BookList2 {
	//Data
	DoublyLinkedList data;
	//java.util.LinkedList<Book> data;
	
	//Constructor
	public BookList2() {
		data = new DoublyLinkedList();
		//data = new java.util.LinkedList<Book>();
	}
	
	//Public methods	
	public int addBook(Book b) {
		boolean flag = false;
		int i = 0;
		for(; i < data.size(); i++) {
			Book w = (Book)data.get(i);
			//Book w = data.get(i);
			if(b.compareTo(w) < 0) {
				data.add(i,b);
				flag = true;
				break;
			}
			else if(b.compareTo(w) == 0) {
				flag = true;
				w.quantity += b.quantity;
				break;
			}
		}
		if(!flag) data.add(i,b);
		return b.quantity;
	}

	public int saleBook(Book b) throws BookNotFoundException {
		for(int i = 0; i < data.size(); i++) {
			Book w = (Book)data.get(i);
			//Book w = data.get(i);
			if(b.compareTo(w) == 0) {
				int q1 = w.quantity;
				int q2 = b.quantity;
				if (q1 > q2) {
					w.quantity = q1 - q2;
					return q2;
				}
				else {
					data.remove(i);
					return q1;
				}
			}
		}
		throw new BookNotFoundException(b.bookID + "  " + b.title + " not found");
	}

	public BookList2 getBooks(String author) {
		BookList2 newList = new BookList2();
		Iterator it = data.iterator();
		//java.util.Iterator<Book> it = data.iterator();
		while(it.hasNext()) {
			Book w = (Book)it.next();
			//Book w = it.next();
			if(author.equals(w.author))
				newList.addBook(w);
		}
		return newList;
	}

	public int doRequest(Request r) {
		int sum = 0;
		if(r.kind == 1)
			for(int i = 0; i < r.books.length; i++)
				sum += addBook(r.books[i]);
		else
			for(int i = 0; i < r.books.length; i++)
				try {
					sum += saleBook(r.books[i]);
				}catch (BookNotFoundException e) {
					System.out.println(e.toString());}
		return sum;
	}

	public void show() {
		Iterator it = data.iterator();
		//java.util.Iterator<Book> it = data.iterator();
		while(it.hasNext())
			System.out.println(it.next());
	}
}