Thread: Can't reassign boolean value!

Hi guys,

I am having an issue with some Java that I have written.

I have a class called Journey and within this class I have some methods. In my code I have a boolean data member set as false by default. Then in a method I change the value of the data member to true if the criteria of an if statement is met.

When I test the code it seems as if the boolean value doesn't get changed to true if the if statement criteria is met which means the boolean value remains as false.

Any ideas regarding what I am doing wrong?

Data members

	private int year = 0;
	private int month = 0;
	private int day = 0;
	private int lastDayOfMonth = 0;
	private boolean discount = false;

Methods

        public void lastDay() {
		SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
		GregorianCalendar date = new GregorianCalendar( year, month, day );
 
		lastDayOfMonth = date.getActualMaximum(GregorianCalendar.DAY_OF_MONTH);
 
		if (day == lastDayOfMonth)
		discount = true;
	}

	public double getPrice() {
		if (discount == true)
		return journeyPrices[departing][destination] * 100;
		else
		return journeyPrices[departing][destination];
	}

The boolean isn't being set as true which is the issue.

Any dates that I input which should meet the criteria of the if statement don't set the boolean to true. It stays false.

Sorry I don't understand where I am supposed to add the println statements.

And how would the discount=true; executed?

I have narrowed down the problem to the lastDayOfMonth = date.getActualMaximum(GregorianCalendar.DAY_OF_MON TH); line.

For some reason that line returns 0 for any form of date when ran in the method however when I just test that one line of code in a main program then it works as intended.

Any idea why the line is returning the wrong value?

Main class

import java.util.*;
import java.text.*;
import javax.swing.*;
 
public class MainClass {
	public static void main(String[]args){
 
		Scanner scanner = new Scanner(System.in);
		Journey journey = new Journey();
 
		System.out.println("Enter the date of travel");
		String userSelection = scanner.next();
 
		journey.setDate(userSelection);
 
                System.out.println( journey.lastDayTest() );
       }
}

Journey Class

import java.util.*;
import java.text.*;
import javax.swing.*;
 
public class Journey {
 
        private int year;
	private int month;
	private int day;
	private int lastDayOfMonth;
	private boolean discount = false;
	private SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
	private GregorianCalendar date = new GregorianCalendar( year, month, day );
 
 
	public void setDate(String userSelection) {
		year = Integer.parseInt( userSelection.substring( 6,userSelection.length() ) );
		month = Integer.parseInt( userSelection.substring(3,5) ) - 1;
		day = Integer.parseInt( userSelection.substring(0,2) );
	}
 
	public String getDate() {		
		return sdf.format( date.getTime() );
	}
 
	public void lastDay() {	
		lastDayOfMonth = date.getActualMaximum(GregorianCalendar.DAY_OF_MONTH);
 
		if (day == lastDayOfMonth)
		discount = true;
	}
 
	public int lastDayTest() {
		return lastDayOfMonth;
	}
 
	public int dayTest() {
		return day;
	}
 
	public int monthTest() {
		return month;
	}
}

Even with hardcoded values, 0 is returned for lastDayOfMonth.

I rewrote part of the code just for testing and put it into a single class and it all works fine. lastDayOfMonth returns the correct value for any date that is input however when it is in a separate class as I have previously posted then it doesn't work.

import java.util.*;
import java.text.*;
import javax.swing.*;
 
public class Test {
	public static void main(String[]args){
 
		Scanner scanner = new Scanner(System.in);
 
		System.out.println("Enter the date of travel");
		String userSelection = scanner.next();
 
		int year = Integer.parseInt( userSelection.substring( 6,userSelection.length() ) );
		int month = Integer.parseInt( userSelection.substring(3,5) ) - 1;
		int day = Integer.parseInt( userSelection.substring(0,2) );
 
		GregorianCalendar date = new GregorianCalendar( year, month, day );
 
		int lastDayOfMonth = date.getActualMaximum(GregorianCalendar.DAY_OF_MONTH);
		System.out.println(lastDayOfMonth);
	}	
}

The data that the program uses is input by the user through a command prompt window. The correct values of year, month and day are being printed.

I have also now narrowed down the issue being related to the date variable but I cannot understand what the issue is.

The date variable seems to be working fine in the main program class but in a separate class with different methods, it doesn't work correctly.

I've fixed it!

A couple of lines of code needed rearranging between methods!

Thanks for your help, I'm sure that I wasn't entirely clear with my problems!

Thanks for the advice guys.

I've amended my code so that values that will be used by multiple methods are class variables and any other variable is local to a particular method.