Java Date Compare compareDates(Date date1, Date date2)

Description

Compares two given valid dates to return a number flag

License

Open Source License

Parameter

Parameter	Description
date1	Date object
date2	Date object

Return

Number flag as per following -1 Inputs are wrong (null) 0 Dates are equal 1 First date is before the second one 2 First date is after the second one

Declaration

public static int compareDates(Date date1, Date date2)

Method Source Code


//package com.java2s;
import java.util.*;
import java.text.*;

public class Main {
    /**/* www. j  ava2s . c  o m*/
     * Default Date format
     */
    public static final String DATE_FORMAT = "dd-MM-yyyy";
    /**
     * MONTH
     */
    public static final int MONTH = 2;
    /**
     * YEAR
     */
    public static final int YEAR = 3;

    /**
     * Compares two given valid dates to return a number flag
     *
     * @param dateStr1 Date format string ('MM/DD/YYYY HH24:MM:SS' format)
     * @param dateStr2 Date format string ('MM/DD/YYYY HH24:MM:SS' format)
     *
     * @return Number flag as per following -1 Inputs are wrong (null) 0 Dates
     * are equal 1 First date is before the second one 2 First date is after the
     * second one
     */
    public static int compareDates(String dateStr1, String dateStr2) {
        // Parse the date
        Date date1 = parseDate(dateStr1);
        Date date2 = parseDate(dateStr2);

        // Return
        return compareDates(date1, date2);
    }

    /**
     * Compares two given valid dates to return a number flag
     *
     * @param date1 Date object
     * @param date2 Date object
     *
     * @return Number flag as per following -1 Inputs are wrong (null) 0 Dates
     * are equal 1 First date is before the second one 2 First date is after the
     * second one
     */
    public static int compareDates(Date date1, Date date2) {
        // Check input
        if (date1 == null || date2 == null) {
            return -1;
        }

        int dateDifference = 0;

        Calendar calendar1 = Calendar.getInstance();
        calendar1.setTime(date1);

        Calendar calendar2 = Calendar.getInstance();
        calendar2.setTime(date2);

        // Retrieve days, months and years for both dates
        int day1 = calendar1.get(Calendar.DATE);
        int month1 = calendar1.get(Calendar.MONTH);
        int year1 = calendar1.get(Calendar.YEAR);

        int day2 = calendar2.get(Calendar.DATE);
        int month2 = calendar2.get(Calendar.MONTH);
        int year2 = calendar2.get(Calendar.YEAR);

        // Compare years
        if (year1 < year2) {
            dateDifference = 1;
        } else if (year1 > year2) {
            dateDifference = 2;
        } // Years are same so compare months
        else {
            if (month1 < month2) {
                dateDifference = 1;
            } else if (month1 > month2) {
                dateDifference = 2;
            } // Months are same so compare days
            else {
                if (day1 < day2) {
                    dateDifference = 1;
                } else if (day1 > day2) {
                    dateDifference = 2;
                } else {
                    dateDifference = 0;
                }
            }
        }

        // Return
        return dateDifference;
    }

    /**
     * Return a Date for the DATE_FORMAT format string
     *
     * @param dateStr Date format string
     *
     * @return Java Date object if the input is valid, else null
     */
    public static Date parseDate(String dateStr) {
        // Check input
        if (dateStr == null) {
            return null;
        }

        // Create the formatter object
        SimpleDateFormat formatter = new SimpleDateFormat(DATE_FORMAT);

        // Do not parse the string if it do not adhere to the format given
        formatter.setLenient(false);

        // Parse
        ParsePosition pos = new ParsePosition(0);
        Date date = formatter.parse(dateStr, pos);

        // Return
        return date;
    }

    /**
     * Return a String for the given java.util.Date as per DATE_FORMAT
     *
     * @param date Date object
     *
     * @return String for the given java.util.Date as per DATE_FORMAT, null in
     * case of error
     */
    public static String parseDate(Date date) {
        // Check input
        if (date == null) {
            return null;
        }

        // Create the formatter object
        SimpleDateFormat formatter = new SimpleDateFormat(DATE_FORMAT);

        // Do not parse the string if it do not adhere to the format given
        formatter.setLenient(false);

        // Parse
        return formatter.format(date);
    }
}