Catalog.java:

import java.util.ArrayList;
public class Catalog
{
 private ArrayList

CatalogItem.java:

public class CatalogItem
{
 private Book book;
 private String uniqueId;
 private boolean available;
 public CatalogItem(Book book, String id, boolean availability)
 {
 this.book = book;
 this.uniqueId = id;
 this.available = availability;
 }
 public Book getBook()
 {
 return this.book;
 }
 public String getId()
 {
 return this.uniqueId;
 }
 public boolean isAvailable()
 {
 return this.available;
 }
 public void setAvailable()
 {
 this.available = true;
 }
 public void setUnavailable()
 {
 this.available = false;
 }
}

Book.java:

public class Book
{
 private String title;
 private String firstName;
 private String lastName;
 public Book(String title, String firstName, String lastName)
 {
 this.title = title;
 this.firstName = firstName;
 this.lastName = lastName;
 }
 public String getTitle()
 {
 return this.title;
 }
 public String getAuthorFirstName()
 {
 return this.firstName;
 }
 public String getAuthorLastName()
 {
 return this.lastName;
 }
 public String toString()
 {
 return new String(this.title+", "+this.firstName+", "+this.lastName);
 }
}