重构_改善既有代码的设计第一章重构例子

/**
 * 
 */
package statedesignmodel;

import java.util.Enumeration;
import java.util.Vector;

/**
 * @author Administrator
 *
 */
public class Customer {

    private String _name;
    private Vector<Rental> _rentals = new Vector<Rental>();

    public Customer(String name) {
        this._name = name;
    }

    public void addRental(Rental arg) {
        this._rentals.addElement(arg);
    }

    public String getName() {
        return _name;
    }

    public String statement() {
        double totalAmount = 0;
        int frequentRenterPoints = 0;
        Enumeration<Rental> rentals = this._rentals.elements();
        String result = "Rental Record for " + this.getName() + "\n";
        while (rentals.hasMoreElements()) {
            double thisAmount = 0;
            Rental each = (Rental) rentals.nextElement();

            switch (each.getMovie().getPriceCode()) {
            case Movie.REGULAR:
                thisAmount += 2;
                if (each.getDaysRented() > 2) {
                    thisAmount += (each.getDaysRented() - 2) * 1.5;
                    break;
                }
            case Movie.NEW_RELEASE:
                thisAmount += each.getDaysRented() * 3;
                break;
            case Movie.CHILDRENS:
                thisAmount += 1.5;
                if (each.getDaysRented() > 3) {
                    thisAmount += (each.getDaysRented() - 3) * 1.5;
                    break;
                }
            }
            // add frequent renter points
            frequentRenterPoints++;
            // add bonus for a two day new release rental
            if ((each.getMovie().getPriceCode() == Movie.NEW_RELEASE)
                    && each.getDaysRented() > 1) {
                frequentRenterPoints++;
            }
            // show figures for this rental
            result += "\t" + each.getMovie().getTitle() + "\t"
                    + String.valueOf(thisAmount) + "\n";
            totalAmount += thisAmount;

        }
        // add footer lines
        result += "Amount owed is " + String.valueOf(totalAmount) + "\n";
        result += "You earned " + String.valueOf(frequentRenterPoints)
                + " frequent renter points";
        return result;
    }
}

/**
 * 
 */
package statedesignmodel;

/**
 * @author Administrator
 *
 */
public class Movie {

    public static final int CHILDRENS = 2;
    public static final int REGULAR = 0;
    public static final int NEW_RELEASE = 1;

    private String _title;
    private int _priceCode;

    public Movie(String title, int priceCode) {
        this._title = title;
        this._priceCode = priceCode;
    }

    public String getTitle() {
        return _title;
    }

    public void setTitle(String _title) {
        this._title = _title;
    }

    public int getPriceCode() {
        return _priceCode;
    }

    public void setPriceCode(int _priceCode) {
        this._priceCode = _priceCode;
    }

}

/**
 * 
 */
package statedesignmodel;

/**
 * @author Administrator
 *
 */
public class Rental {
    private Movie _movie;
    private int _daysRented;

    public Rental(Movie movie, int daysRented) {
        this._movie = movie;
        this._daysRented = daysRented;
    }

    public Movie getMovie() {
        return _movie;
    }

    public int getDaysRented() {
        return _daysRented;
    }

}