public class Main {

    public static void main(String[] args) {
        Library library = new Library();

        library.addBook("Java For Begginers", "2017", "Jakub Niedzielski");
        library.addBook("Java Podstawy Wydanie X", "2016", "Cay S. Horstmann");
        library.addBook("Java. Przewodnik dla początkujących. Wydanie V", "2012", "Herbert Schildt");
        library.addBook("Capitalism: The unknown ideal", "1966", "Ayn Rand");
        library.addBook("Atlas shrugged", "1957", "Ayn Rand");
        library.addBook("Java For Dumbasses", "2017", "Jakub Niedzielski");
        library.addBook("Effective Java: Programming Language Guide", "2017", "Joshua Bloch");
        library.addBook("Java Performance", "2016", "Charlie Hunt");

        library.lendBook(3);
        library.removeBook(3);


    }

}

import java.util.HashMap;
import java.util.Map;

public class Library {

    private int uniqueID = 0;
    private Map<Integer, Book> bookMap = new HashMap<>();

    public void addBook(String title, String year, String author) {
        uniqueID++;
        Book newBook = new Book(title, year, author, uniqueID);
        bookMap.put(uniqueID, newBook);

    }

    public void getInfoByID(Integer bookID) {
        Book book = bookMap.get(bookID);
        if (book != null) {
            book.print();
        }
    }

    public void getStatusInfo(Integer bookID) {
        Book statusInfo = bookMap.get(bookID);
        System.out.println("The book of ID: " + bookID + " is " + statusInfo.getBookStatus());
    }

    public void lendBook(Integer bookID) {
        Book bookStatus = bookMap.get(bookID);
        bookStatus.lendBook();
    }

    public void recoverBook(Integer bookID) {
        Book bookStatus = bookMap.get(bookID);
        bookStatus.recoverBook();
    }

    public void removeBook(Integer bookID) {
        Book value = bookMap.get(bookID);
        if (value != null) {
            if (value.getEnumBookStatus().equals(BookStatus.AVAILABLE)) {
                bookMap.remove(bookID);
            } else {
                System.out.println("Can't remove that book right now");
            }
        } else {
            System.out.println("Invalid ID number");

        }

    }

    public void getAll() {
        for (Book book : bookMap.values()) {
            book.print();
        }
    }

    public void getAllByAuthor(String author) {
        for (Book book : bookMap.values()) {
            if (author.equals(book.getAuthor())) {
                book.print();
            }
        }
    }

    public void getAllByYear(String year) {
        for (Book book : bookMap.values()) {
            if (year.equals(book.getYear())) {
                book.print();
            }
        }
    }

    // forbid to lent a book if its already lent
    // should allow to pass the name of person who lent it

    public Library() {

    }

}



public class Book {

    private int id;
    private String title;
    private String year;
    private String author;
    private BookStatus bookStatus = BookStatus.AVAILABLE;

    public Book(String title, String year, String author, int uniqueID) {
        this.id = uniqueID;
        this.title = title;
        this.year = year;
        this.author = author;

    }

    public String getTitle() {
        return title;
    }

    public String getYear() {
        return year;
    }

    public String getAuthor() {
        return author;
    }

    public int getId() {
        return id;
    }

    public void lendBook() {
        bookStatus = BookStatus.NON_AVAILABLE;
    }

    public void recoverBook() {
        bookStatus = BookStatus.AVAILABLE;
    }

    public String getBookStatus() {
        return bookStatus.toString();
    }

    public BookStatus getEnumBookStatus() {
        return bookStatus;
    }

    public void print() {
        System.out.println("ID number: " + this.getId());
        System.out.println("Title: " + this.getTitle());
        System.out.println("Year: " + this.getYear());
        System.out.println("Author: " + this.getAuthor());
        System.out.println("The book is " + this.getBookStatus());
        System.out.println();
    }

}


enum BookStatus {
    AVAILABLE {
        @Override
        public String toString() {
            return "available";
        }
    },
    NON_AVAILABLE {
        @Override
        public String toString() {
            return "non available";
        }
    }

}