Java Date Subtract subtractDurationToDate(Date date, String duration)

Description

Subtracts duration to date

License

Open Source License

Parameter

Parameter	Description
date	a Date
duration	a String formated like "P##Y##M##D"

Return

a Date

Declaration

public static Date subtractDurationToDate(Date date, String duration) 

Method Source Code

//package com.java2s;
/*//  w ww . j  av a 2  s .  c om
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 * 
 *    (C) 2006-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 */

import java.util.Calendar;
import java.util.Date;

public class Main {
    private static final Calendar CALENDAR = Calendar.getInstance();
    private static final int YEARS = 0;
    private static final int MONTHS = 1;
    private static final int DAYS = 2;
    private static final int HOURS = 0;
    private static final int MINUTES = 1;
    private static final int SECONDS = 2;
    /** H,M,S */
    private static int[] DURATION_TIME = new int[3];

    /**
     * Subtracts duration to date
     *
     * @param date
     *            a Date
     * @param duration
     *            a String formated like "P##Y##M##D"
     *
     * @return a Date
     */
    public static Date subtractDurationToDate(Date date, String duration) {
        final int negative = -1;

        Date computedDate = null;

        computedDate = computeDateFromDurationDate(date, duration, negative);

        computedDate = computeDateFromDurationTime(computedDate, duration, negative);

        return computedDate;
    }

    /**
     * Adds years, month and days (duration) to initial date.
     *
     * @param date
     *            initial date
     * @param duration
     *            a String with format: PddYddMddD
     * @return Date a computed date. if duration have not got duration "P"
     *         return date value.
     *
     */
    private static Date computeDateFromDurationDate(final Date date, final String duration, int sign) {

        int[] durationDate = new int[3];
        durationDate = extractDurationDate(duration);

        if (isNull(durationDate)) {
            return date;
        }

        CALENDAR.setTime(date);

        // years
        if (durationDate[YEARS] >= 0) {
            CALENDAR.add(Calendar.YEAR, sign * durationDate[YEARS]);
        }

        // months
        if (durationDate[MONTHS] >= 0) {
            CALENDAR.add(Calendar.MONTH, sign * durationDate[MONTHS]);
        }

        // days
        if (durationDate[DAYS] >= 0) {
            CALENDAR.add(Calendar.DATE, sign * durationDate[DAYS]);
        }

        Date lastDate = CALENDAR.getTime();

        return lastDate;
    }

    /**
     * Add or subtract time duration to initial date.
     *
     * @param date
     *            initial date
     * @param duration
     *            a String with format: TddHddMddS
     * @param sign
     *            1 or -1 (add or subract)
     * @return Date a computed date. if duration have not got duration "T"
     *         return date value.
     */
    private static Date computeDateFromDurationTime(final Date date, final String duration, final int sign) {
        DURATION_TIME = extractDurationTime(duration);

        if (isNull(DURATION_TIME)) {
            return date;
        }

        CALENDAR.setTime(date);

        // hours
        if (DURATION_TIME[HOURS] >= 0) {
            CALENDAR.add(Calendar.HOUR, sign * DURATION_TIME[HOURS]);
        }

        // minute
        if (DURATION_TIME[MINUTES] >= 0) {
            CALENDAR.add(Calendar.MINUTE, sign * DURATION_TIME[MINUTES]);
        }

        // seconds
        if (DURATION_TIME[SECONDS] >= 0) {
            CALENDAR.add(Calendar.SECOND, sign * DURATION_TIME[SECONDS]);
        }

        Date lastDate = CALENDAR.getTime();

        return lastDate;
    }

    /**
     * Extract from duration string the values of years, month and days
     *
     * @param duration
     * @return int[3] with years,months,days, if some value are not present -1
     *         will be returned.
     */
    private static int[] extractDurationDate(final String duration) {
        // initializes duration date container
        /** Y,M,D */
        int[] durationDate = new int[3];

        for (int i = 0; i < durationDate.length; i++) {
            durationDate[i] = -1;
        }

        // if has not duration date return array with -1 values
        int cursor = duration.indexOf("P");

        if (cursor == -1) {
            return durationDate;
        }

        // extracts duration date and set duration array
        cursor++;

        // years
        int endYears = duration.indexOf("Y", cursor);

        if (endYears >= 0) {
            String strYears = duration.substring(cursor, endYears);
            int years = Integer.parseInt(strYears);
            durationDate[YEARS] = years;

            cursor = endYears + 1;
        }

        // months
        int endMonths = duration.indexOf("M", cursor);

        if (endMonths >= 0) {
            String strMonths = duration.substring(cursor, endMonths);
            int months = Integer.parseInt(strMonths);
            durationDate[MONTHS] = months;

            cursor = endMonths + 1;
        }

        // days
        int endDays = duration.indexOf("D", cursor);

        if (endDays >= 0) {
            String strDays = duration.substring(cursor, endDays);
            int days = Integer.parseInt(strDays);
            durationDate[DAYS] = days;
        }

        return durationDate;
    }

    /**
     * durDate is null if all his values are -1
     *
     * @param durDate
     * @return true if has some greater than or equal 0
     */
    private static boolean isNull(int[] durDate) {
        for (int i = 0; i < durDate.length; i++) {
            if (durDate[i] >= 0) {
                return false;
            }
        }

        return true;
    }

    /**
     * Extract from duration string the values of hours, minutes and seconds
     *
     * @param duration
     * @return int[3] with hours, minutes and seconds if some value are not
     *         present -1 will be returned.
     */
    private static int[] extractDurationTime(final String duration) {
        for (int i = 0; i < DURATION_TIME.length; i++) {
            DURATION_TIME[i] = -1;
        }

        int cursor = duration.indexOf("T");

        if (cursor == -1) {
            return DURATION_TIME;
        }

        cursor++;

        // hours
        int endHours = duration.indexOf("H", cursor);

        if (endHours >= 0) {
            String strHours = duration.substring(cursor, endHours);
            int hours = Integer.parseInt(strHours);
            DURATION_TIME[HOURS] = hours;

            cursor = endHours + 1;
        }

        // minute
        int endMinutes = duration.indexOf("M", cursor);

        if (endMinutes >= 0) {
            String strMinutes = duration.substring(cursor, endMinutes);
            int minutes = Integer.parseInt(strMinutes);
            DURATION_TIME[MINUTES] = minutes;

            cursor = endMinutes + 1;
        }

        // seconds
        int endSeconds = duration.indexOf("S", cursor);

        if (endSeconds >= 0) {
            String strSeconds = duration.substring(cursor, endSeconds);
            int seconds = Integer.parseInt(strSeconds);
            DURATION_TIME[SECONDS] = seconds;
        }

        return DURATION_TIME;
    }
}

Related

1. subtractCertainYears(java.util.Date date, Integer years)
2. subtractDate(Date date, int type, Integer quantity)
3. subtractDate(Date date, int type, Integer quantity)
4. subtractDay(final Date date)
5. subtractDays(Date dt, int days)
6. subtractNowDay(Date date)
7. subtractOrAddDayDuration(Date date, int duration)