import java.util.LinkedList;

public class Library {

	private LinkedList<Medium> liste;
	//                 ‾‾‾‾‾‾ -> Medium für E eingesetzt (Generics)
	
	public Library() {
		liste = new LinkedList<Medium>(); // leere Liste anlegen
	}
	
	public void add(Medium b) {
		if (!liste.contains(b)) // 1. Prüfe, ob enthalten
			liste.add(b);
	}

	public Medium get(long id) {
		//for (int i = 0; i < liste.size(); i++) {
		//	Book b = liste.get(i);
		for (Medium b : liste)
			if (b.getIdNr() == id)
				return b;
		return null;
	}
	
	public boolean delete(Medium b) {
		return liste.remove(b);
	}
	
	public LinkedList<Book> getBooksWrittenBy(String author) {
		if (author == null)
			return new LinkedList<Book>();
		
		LinkedList<Book> found = new LinkedList<Book>();
		
		for (Medium m : liste) {
			if (m instanceof Book) {
				Book b = (Book) m; 
				if (author.equals(b.getAutor()))
					found.add(b);
			}
		}
		
		return found;
	}
}