Thread: Creating Random unused ID number for every library member.

ok looking at simpleDateFormat

Originally Posted by clarky2006

ok looking at simpleDateFormat

Still not able to print loan details..

Originally Posted by Norm

Please show what you are having problems with.


See Dates and Times (The Java™ Tutorials > Internationalization > Formatting)

Hia...Still having problems with my codes, nearly done now but the loan class is giving me headache..

/**
 * This Class would hold all loan details.
 * 
 * @author () 
 * @version 1.0
 */
public class Loan
{
    // fields for the Loan Class.
    private int bookId;
    private int memberId;
    private GregorianCalendar loanDate;
    private GregorianCalendar dateDueBack;
    private String month = "";
    private String day = "";
    private String year = "";
    private String currentDate = "";
 
 
    /**
     * Constructor for objects of class Loan
     */
    public Loan(int bookId, int memberId)
    {
        // initialised fields.
        this.bookId = bookId;
        this.memberId = memberId;
        this.loanDate = new GregorianCalendar();
 
        GregorianCalendar gregorianCalendar=new GregorianCalendar();            
        month=String.valueOf(gregorianCalendar.get(GregorianCalendar.MONTH));            
        day=String.valueOf(gregorianCalendar.get(GregorianCalendar.DAY_OF_MONTH));
        year=String.valueOf(gregorianCalendar.get(GregorianCalendar.YEAR));
        currentDate = (day + " / " + month + " / " + year);
 
 
 
    }

Here im trying to define date when loan is taken out with gregorian Calendar..when a loan object is created a date stamp should be created to be the loan date at the same time, so i can call the getLoandate an get that time. I want to add 21 days to the loan date and be be able to call it via get dateDueBack. Im not sure how to add 21 days to the loandate to accomplish this. please help....thanks

I tried it earlier in the construtor but it did not work..ok i ll try it again..have to submit the project on friday...thanx

Originally Posted by Norm

When you have code that 'does not work', you should post it and explain what it does and ask about how to have it do what you want it to do.

ok I ll take note..

--- Update ---

Originally Posted by clarky2006

Hia...Still having problems with my codes, nearly done now but the loan class is giving me headache..

/**
 * This Class would hold all loan details.
 * 
 * @author () 
 * @version 1.0
 */
public class Loan
{
    // fields for the Loan Class.
    private int bookId;
    private int memberId;
    private GregorianCalendar loanDate;
    private GregorianCalendar dateDueBack;
    private String month = "";
    private String day = "";
    private String year = "";
    private String currentDate = "";
 
 
    /**
     * Constructor for objects of class Loan
     */
    public Loan(int bookId, int memberId)
    {
        // initialised fields.
        this.bookId = bookId;
        this.memberId = memberId;
        this.loanDate = new GregorianCalendar();
 
        GregorianCalendar gregorianCalendar=new GregorianCalendar();            
        month=String.valueOf(gregorianCalendar.get(GregorianCalendar.MONTH));            
        day=String.valueOf(gregorianCalendar.get(GregorianCalendar.DAY_OF_MONTH));
        year=String.valueOf(gregorianCalendar.get(GregorianCalendar.YEAR));
        currentDate = (day + " / " + month + " / " + year);
 
 
 
    }

Here im trying to define date when loan is taken out with gregorian Calendar..when a loan object is created a date stamp should be created to be the loan date at the same time, so i can call the getLoandate an get that time. I want to add 21 days to the loan date and be be able to call it via get dateDueBack. Im not sure how to add 21 days to the loandate to accomplish this. please help....thanks

public void add(int loanDate, int amount)
    {
        Calendar cal = new GregorianCalendar();
        cal.add(loanDate, + 21);
 
 
    }

Here is the add method, it says "cannot find symbol class calendar"

Originally Posted by Norm

All java class names start with Uppercase letters. Try using Calendar.

Calendar is in Capital...

no but i do have Gregorian calendar imported

--- Update ---

Originally Posted by clarky2006

no but i do have Gregorian calendar imported

wow..just imported calendar and its compiled...i see if it works..you are a star...cheers

--- Update ---

at Loan.getDateDueBack(Loan.java:85)
at Loan.toString(Loan.java:95)
java.lang.NullPointerException
at Loan.setDateDueBack(Loan.java:75)

this is what i get with the add method

ok i will

--- Update ---

     /**
     * Get the date of the loan.
     * @return
     */
    public GregorianCalendar getLoandDate()
    {
        return (GregorianCalendar) loanDate.clone();
    }

Here is the code on line 75

The Loan date isjava.util.GregorianCalendar[time=1355021169274,areFieldsSet=true,areAllFieldsS et=true,lenient=true,zone=sun.util.calendar.ZoneIn fo[id="Europe/London",offset=0,dstSavings=3600000,useDaylight=tr ue,transitions=242,lastRule=java.util.SimpleTimeZo ne[id=Europe/London,offset=0,dstSavings=3600000,useDaylight=tru e,startYear=0,startMode=2,startMonth=2,startDay=-1,startDayOfWeek=1,startTime=3600000,startTimeMode =2,endMode=2,endMonth=9,endDay=-1,endDayOfWeek=1,endTime=3600000,endTimeMode=2]],firstDayOfWeek=2,minimalDaysInFirstWeek=4,ERA=1,Y EAR=2012,MONTH=11,WEEK_OF_YEAR=49,WEEK_OF_MONTH=1, DAY_OF_MONTH=9,DAY_OF_YEAR=344,DAY_OF_WEEK=1,DAY_O F_WEEK_IN_MONTH=2,AM_PM=0,HOUR=2,HOUR_OF_DAY=2,MIN UTE=46,SECOND=9,MILLISECOND=274,ZONE_OFFSET=0,DST_ OFFSET=0]

This is what i get when i print the loan Date...I think I need to assign the current date to the loanDate, but i dont know how to do it..i ve declared current date in the field.

this.loanDate = new GregorianCalendar(); Im trying to assign the current date to the loanDate here but I dont think the code is right....

--- Update ---

the value for the loandate date should be when the loan object is created.......

/**
 * This Class would hold all loan details.
 * 
 * @author () 
 * @version 1.0
 */
public class Loan
{
    // fields for the Loan Class.
    private int bookId;
    private int memberId;
    private GregorianCalendar loanDate;
    private GregorianCalendar dateDueBack;
    private String month = "";
    private String day = "";
    private String year = "";
    private String currentDate = "";
 
 
    /**
     * Constructor for objects of class Loan
     */
    public Loan(int bookId, int memberId)
    {
        // initialised fields.
        this.bookId = bookId;
        this.memberId = memberId;
        this.loanDate = new GregorianCalendar();
 
        GregorianCalendar gregorianCalendar=new GregorianCalendar();          
        month=String.valueOf(gregorianCalendar.get(GregorianCalendar.MONTH));            
        day=String.valueOf(gregorianCalendar.get(GregorianCalendar.DAY_OF_MONTH));
        year=String.valueOf(gregorianCalendar.get(GregorianCalendar.YEAR));
        currentDate = (day + " / " + month + " / " + year);
 
 
 
 
 
 
    }
 
 
    /**
     * Set date when the loan was taken out.
     * 
     * @param date the day of the month 1 to 28, 30 or 31 depending on month
     * @param month 1 (January) to 12 December
     * @param year the year including century e.g. 2010
     */
    public void setLoanDtae(int date, int month, int year)
    {
        loanDate.set(date, month - 1, year);
    }
 
    public void add(int loanDate, int amount)
    {
        Calendar cal = new GregorianCalendar();
        cal.add(loanDate, + 21);
 
 
    } 
 
 
 
 
     /**
     * Get the date of the loan.
     * @return
     */
    public GregorianCalendar getLoandDate()
    {
        System.out.println(loanDate);
        return (GregorianCalendar) loanDate.clone();
 
    } 
 
     /**
     * Get date when loan is due back.
     * @return
     */
    public GregorianCalendar getDateDueBack()
    {
 
        return (GregorianCalendar) dateDueBack.clone();
    }
 
    /**
     * Return date when loan is due back as a String.
     */
    public String toString()
    {
        String s = new String();
        s = memberId + " " + bookId + " Loan ";
        s += getDateDueBack();
        return s;
    } 
 
    /**
     * 
     * 
     */
    public void printLoanDetails()
    {
       System.out.println("Member ID:"  +  memberId);
       System.out.println("Book ID:"  +  bookId);
       System.out.println("The Loan date is" + loanDate);
       GregorianCalendar calendar = new GregorianCalendar();
       int day = calendar.get(Calendar.DATE);
       int month = calendar.get(Calendar.MONTH);
       int year = calendar.get(Calendar.YEAR);
        //
       System.out.println("The Loan date is "
        + calendar.get(Calendar.DATE) + " "
        + (calendar.get(Calendar.MONTH) + 1) + " "
        + calendar.get(Calendar.YEAR));

Here is the whole code in the Loan Class..That was the message I was getting......

ok thanks for your help....me too im off to bed...I go to sleep dreaming and thinking of codes...its driving me crazy....

Morning...its a new day and more coding to be done....Today i need to be able to initialise loanDate and give its value to the field..instead of creating a parameter to pass it through..

import java.util.GregorianCalendar;
import java.util.Calendar;
import java.util.*;
import java.util.*;
/**
 * This Class would hold all loan details.
 * 
 * @author () 
 * @version 1.0
 */
public class Loan
{
    // fields for the Loan Class.
    private int bookId;// The borrower's unique ID.
    private int memberId;// The book's unique Identification number.
    private GregorianCalendar loanDate;// The date when loan was taken out.
    private GregorianCalendar dateLoanDueBack;// The date when loan is due back.
 
    /**
     * Constructor for objects of class Loan
     */
    public Loan(int bookId, int memberId)
    {
        // initialised fields.
        this.bookId = bookId;
        this.memberId = memberId;
        loanDate = new GregorianCalendar();
        dateLoanDueBack = new GregorianCalendar();
        dateLoanDueBack.add(dateLoanDueBack.Date, 21);
 
    }
 
    public Loan()
    {
 
 
 
    }   
 
    /**
     * Set date when the loan was taken out.
     * 
     * @param date the day of the month 1 to 28, 30 or 31 depending on month
     * @param month 1 (January) to 12 December
     * @param year the year including century e.g. 2010
     */
    public void setLoanDtae(int date, int month, int year)
    {
        loanDate.set(date, month - 1, year);
    }
 
     public String getDateLoanDueBack()
     {
        SimpleDateFormat df = new SimpleDateFormat("dd MMM yyyy");   
           return df.format(dateLoanDueBack.getTime()); 
     }
 
     /**
     * Get the date of the loan.
     * @return
     */
    public GregorianCalendar getLoanDate()
    {
       SimpleDateFormat df = new SimpleDateFormat("dd MMM yyyy");
        return df.format(loanDate.getTime());
 
    }
 
         /**
     * Get date when loan is due back.
     * @return
     */
    public GregorianCalendar getDateDueBack()
    {
 
        return (GregorianCalendar) dateDueBack.clone();
    }
 
    /**
     * Return date when loan is due back as a String.
     */
    public String toString()
    {
        String s = new String();
        s = memberId + " " + bookId + " Loan ";
        s += getDateDueBack();
        return s;
    } 
 
    /**
     * 
     * 
     */
    public void printLoanDetails()
    {
       System.out.println("Member ID:"  +  memberId);
       System.out.println("Book ID:"  +  bookId);
       System.out.println("The Loan date is" + loanDate);
       System.out.println("The due back date for this loan is:" + dateLoanDueBack);
    } 
}

Hi mate I have re-written the loan class but im getting an error message "cannot find Symbol - variable Date" help please.........

Originally Posted by Norm

If that message is from the compiler, (it looks different from normal compiler error messages)
then the compiler can not find a definition for the variable: Date.
BTW conventions say variable names should start with lowercase names. Using an uppercase first letter is for class names.

What line in the code is getting the error message? That is shown on the normal compiler error message.
Where is the variable: Date defined?

/**
* Constructor for objects of class Loan
*/
public Loan(int bookId, int memberId)
{
// initialised fields.
this.bookId = bookId;
this.memberId = memberId;
loanDate = new GregorianCalendar();
dateLoanDueBack = new GregorianCalendar();
dateLoanDueBack.add(dateLoanDueBack.Date, 21);

}

dateLoanDueBack.add(dateLoanDueBack.Date, 21); Its complaining about the date here(Date) Im trying to use the add method to add 21 days here for the due back date during initialisation.....