Constructors

package aaa;
import java.io.*;
public class Date {
private String month;
private int day;
private int year;
public Date() {
month = "Jan";
day = 1;
year = 1000;
}

public Date(int monthInt, int day, int year) {
setDate(monthInt, day, year);
}

public Date(String monthString, int day, int year) {
setDate(monthString, day, year);
}

public Date(int year) {
setDate(1, 1, year);
}

public Date(Date aDate) {
if (aDate == null) {
System.out.println("Fatal Error.");
System.exit(0);
}
month = aDate.month;
day = aDate.day;
year = aDate.year;
}

public void setDate(int monthInt, int day, int year) {
if (dateOK(monthInt, day, year)) {
this.month = monthString(monthInt);
this.day = day;
this.year = year;
} else {
System.out.println("Fatal Error");
System.exit(0);
}
}

public void setDate(String monthString, int day, int year) {
if (dateOK(monthString, day, year)) {
this.month = monthString;
this.day = day;
this.year = year;
} else {
System.out.println("Fatal Error");
System.exit(0);
}
}

public void setDate(int year) {
setDate(1, 1, year);
}

public void setYear(int year) {
if ((year <> 9999)) {
System.out.println("Fatal Error");
System.exit(0);
} else {
this.year = year;
}
}

public void setMonth(int monthNumber) {
if ((monthNumber <= 0) || (monthNumber > 12)) {
System.out.println("Fatal Error");
System.exit(0);
} else {
month = monthString(monthNumber);
}
}

public void setDay(int day) {
if ((day <= 0) || (day > 31)) {
System.out.println("Fatal Error");
System.exit(0);
} else {
this.day = day;
}
}

public int getMonth() {
if (month.equals("Jan")) {
return 1;
} else if (month.equals("Feb")) {
return 2;
} else if (month.equals("Mar")) {
return 3;
} else if (month.equals("Apr")) {
return 4;
} else if (month.equals("May")) {
return 5;
} else if (month.equals("Jun")) {
return 6;
} else if (month.equals("Jul")) {
return 7;
} else if (month.equals("Aug")) {
return 8;
} else if (month.equals("Sep")) {
return 9;
} else if (month.equals("Oct")) {
return 10;
} else if (month.equals("Nov")) {
return 11;
} else if (month.equals("Dec")) {
return 12;
} else {
System.out.println("Fatal Error");
System.exit(0);
return 0;
}
}

public int getDay() {
return day;
}

public int getYear() {
return year;
}

public String toString() {
return (month + " " + day + ", " + year);
}

public boolean equals(Date otherDate) {
return ((month.equals(otherDate.month))
&& (day == otherDate.day) && (year == otherDate.year));
}

public boolean precedes(Date otherDate) {
return ((year <>
(year == otherDate.year && getMonth() <>
(year == otherDate.year && month.equals(otherDate.month)
&& day <>
}

public void readInput() throws IOException {
boolean tryAgain = true;
BufferedReader keyboard = new BufferedReader(
new InputStreamReader(System.in));
while (tryAgain) {
System.out.println(
"Enter month, day, and year.");
System.out.println(
"Do not ues comma.");
int monthInput = Integer.parseInt(keyboard.readLine());
int dayInput = Integer.parseInt(keyboard.readLine());
int yearInput = Integer.parseInt(keyboard.readLine());
if (dateOK(monthInput, dayInput, yearInput)) {
setDate(monthInput, dayInput, yearInput);
tryAgain = false;
} else {
System.out.println("Illegal date. Reenter input.");
}
}
}

private boolean dateOK(int monthInt, int dayInt, int yearInt) {
return ((monthInt >= 1) && (monthInt <= 12) &&
(dayInt >= 1) && (dayInt <= 31) &&
(yearInt >= 1000) && (yearInt <= 9999));
}

private boolean dateOK(String monthString, int dayInt, int yearInt) {
return (monthOK(monthString) &&
(dayInt >= 1) && (dayInt <= 31) &&
(yearInt >= 1000) && (yearInt <= 9999));
}

private boolean monthOK(String month) {
return (month.equals("Jan") || month.equals("Feb") ||
month.equals("Mar") || month.equals("Apr") ||
month.equals("May") || month.equals("Jun") ||
month.equals("Jul") || month.equals("Aug") ||
month.equals("Sep") || month.equals("Oct") ||
month.equals("Nov") || month.equals("Dec"));
}

private String monthString(int monthNumber) {
switch (monthNumber) {
case 1:
return "Jan";
case 2:
return "Feb";
case 3:
return "Mar";
case 4:
return "Apr";
case 5:
return "May";
case 6:
return "Jun";
case 7:
return "Jul";
case 8:
return "Aug";
case 9:
return "Sep";
case 10:
return "Oct";
case 11:
return "Nov";
case 12:
return "Dec";
default:
System.out.println("Fatal Error");
System.exit(0);
return "Error";
}
}
}

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package aaa;
class ConstructorsDemo {
public static void main(String[] args) {
Date date1 = new Date("Dec", 16, 1770), date2 = new Date(1, 27, 1756),
date3 = new Date(1882), date4 = new Date();

System.out.println("Whose birthday is " + date1 + "?");
System.out.println("Whose birthday is " + date2 + "?");
System.out.println("Whose birthday is " + date3 + "?");
System.out.println("The default date is " + date4 + ".");
}
}