私は2つのクラスを一緒にリンクする任務を負っています。最初のクラスは、人がチケットを購入し、それを (System.out.println を介して) 印刷できるチケット マシンです。2 番目のクラスは、時刻を表示する時計表示です。
私の仕事は、現在時計表示クラスに表示されている時間をチケットクラスに出力させることです。NumberDisplay クラスも ClockDisplay クラスも編集する必要はないと言われました。
最初に考えたのは、ticketmachine クラス内に新しい ClockDisplay フィールドを作成し、それを使用することでした。
System.out.println("Time:" + ClockDisplay.displayString);
displayString は、clockdisplay クラス内で値を見つけるために使用するものです。ただし、フィールドはプライベートであり、clockdisplay クラスを編集できないため、これを行うことはできません。何かご意見は？
ありがとうございました。これまでのコードは、TicketMachine クラスの前述のコード部分です。
数値表示
public class NumberDisplay
{
private int limit;
private int value;
/**
* Constructor for objects of class NumberDisplay.
* Set the limit at which the display rolls over.
*/
public NumberDisplay(int rollOverLimit)
{
limit = rollOverLimit;
value = 0;
}
/**
* Return the current value.
*/
public int getValue()
{
return value;
}
/**
* Return the display value (that is, the current value as a two-digit
* String. If the value is less than ten, it will be padded with a leading
* zero).
*/
public String getDisplayValue()
{
if(value < 10) {
return "0" + value;
}
else {
return "" + value;
}
}
/**
* Set the value of the display to the new specified value. If the new
* value is less than zero or over the limit, do nothing.
*/
public void setValue(int replacementValue)
{
if((replacementValue >= 0) && (replacementValue < limit)) {
value = replacementValue;
}
}
/**
* Increment the display value by one, rolling over to zero if the
* limit is reached.
*/
public void increment()
{
if ((value +1) >= limit) {
value = 0;
}
else {
value = value + 1;
}
}
}
時計表示
public class ClockDisplay
{
private NumberDisplay hours;
private NumberDisplay minutes;
private NumberDisplay seconds;
private String displayString; // simulates the actual display
/**
* Constructor for ClockDisplay objects. This constructor
* creates a new clock set at 12:00:00.
*/
public ClockDisplay()
{
hours = new NumberDisplay(12); // changed from 24hour to 12 hour
minutes = new NumberDisplay(60);
seconds = new NumberDisplay(60);
updateDisplay();
}
/**
* Constructor for ClockDisplay objects. This constructor
* creates a new clock set at the time specified by the
* parameters.
*/
public ClockDisplay(int hour, int minute, int second)
{
hours = new NumberDisplay(12); //changed from 24hour to 12 hour
minutes = new NumberDisplay(60);
seconds = new NumberDisplay(60);
setTime(hour, minute, second);
}
/**
* This method should get called once every minute - it makes
* the clock display go one minute forward.
*/
public void timeTick()
{
minutes.increment();
if(minutes.getValue() == 0) { // it just rolled over!
hours.increment();
}
updateDisplay();
}
/**
* Set the time of the display to the specified hour and
* minute and second.
*/
public void setTime(int hour, int minute, int second)
{
if (hour == 12) { //changing the display from '00:00' to '12:00'
hour = 0;
}
hours.setValue(hour);
minutes.setValue(minute);
seconds.setValue(second);
updateDisplay();
}
/**
* Return the current time of this display in the format HH:MM:SS.
*/
public String getTime()
{
return displayString;
}
/**
* Update the internal string that represents the display.
*/
private void updateDisplay()
{
int hour = hours.getValue(); //changes the display to from showing '00:00' to '12:00'
if (hour == 0) {
hour = 12;
}
displayString = hour + ":" +
minutes.getDisplayValue() + ":" + seconds.getDisplayValue();
}
}
券売機
public class TicketMachine
{
// The price of a ticket from this machine.
private int price;
// The amount of money entered by a customer so far.
private int balance;
// The total amount of money collected by this machine.
private int total;
// The time from the clockdisplay class
private ClockDisplay time;
/**
* Create a machine that issues tickets of the given price.
*/
public TicketMachine(int cost)
{
price = cost;
balance = 0;
total = 0;
}
/**
* @Return The price of a ticket.
*/
public int getPrice()
{
return price;
}
/**
* Return The amount of money already inserted for the
* next ticket.
*/
public int getBalance()
{
return balance;
}
/**
* Receive an amount of money from a customer.
* Check that the amount is sensible.
*/
public void insertMoney(int amount)
{
if(amount > 0) {
balance = balance + amount;
}
else {
System.out.println("Use a positive amount rather than: " +
amount);
}
}
/**
* Print a ticket if enough money has been inserted, and
* reduce the current balance by the ticket price. Print
* an error message if more money is required.
*/
public void printTicket()
{
if(balance >= price) {
// Simulate the printing of a ticket.
System.out.println("##################");
System.out.println("# The BlueJ Line");
System.out.println("# Ticket");
System.out.println("# " + price + " cents.");
System.out.println("##################");
System.out.println();
// Update the total collected with the price.
total = total + price;
// Reduce the balance by the prince.
balance = balance - price;
// Print the current time from the NumberDisplay class.
System.out.println("Time:" + ClockDisplay.displayString);
}
else {
System.out.println("You must insert at least: " +
(price - balance) + " more cents.");
}
}
/**
* Return the money in the balance.
* The balance is cleared.
*/
public int refundBalance()
{
int amountToRefund;
amountToRefund = balance;
balance = 0;
return amountToRefund;
}
}