javaInheritance

/**
 * A subunit is either an employee unit or a department unit
 * 
 */
public abstract class Subunit {
	public abstract double total();	
	public abstract void cut();
}

/**
 * A department has a name, a manager and a list of subunits
 * 
 */
public class Department extends Subunit implements Serializable {

	private static final long serialVersionUID = -2008895922177165250L;

	private String name;
	private Employee manager;
	private List<Subunit> subunits = new LinkedList<Subunit>();

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Employee getManager() {
		return manager;
	}

	public void setManager(Employee manager) {
		this.manager = manager;
	}

	public List<Subunit> getSubunits() {
		return subunits;
	}

	public double total() {
		double total = 0;
		total += getManager().total();
		for (Subunit s : getSubunits())
			total += s.total();
		return total;		
	}	
	
	public void cut() {
		getManager().cut();
		for (Subunit s : getSubunits())
			s.cut();
	}	
}

    /*
     * Read (say, deserialize) a company.
     */
    public static Company deserializeCompany(String filename) {

        Object o = null;

        try {
            FileInputStream fis = new FileInputStream(filename);
            ObjectInputStream in = new ObjectInputStream(fis);
            o = in.readObject();
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return (Company) o;
    }

    /*
     * Write (say, serialize) a company.
     */
    public static boolean serializeCompany(Company c, String filename) {

        FileOutputStream fos = null;
        ObjectOutputStream out = null;

        try {
            fos = new FileOutputStream(filename);
            out = new ObjectOutputStream(fos);
            out.writeObject(c);
            out.close();
            return true;
        } catch (IOException ex) {
            ex.printStackTrace();
            return false;
        }
    }

    public static double total(Company c) {
        // Total is implemented in the Company class
        return c.total();
    }

    public static void cut(Company c) {
        // Cut is implemented in the Company class
        c.cut();
    }