serialdate.java

非常实用的java描述的excel组件

/* =================================================
 * JWorkbook : data export from Java to spreadsheets
 * =================================================
 *
 * Project Info:  http://www.jfree.org/jworkbook/index.html;
 * Project Lead:  David Gilbert ([e-mail]);
 *
 * (C) Copyright 2001-2003, by Object Refinery Limited.
 *
 * 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;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * ---------------
 * SerialDate.java
 * ---------------
 * (C) Copyright 2001-2003, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: SerialDate.java,v 1.2 2003/05/29 09:46:19 mungady Exp $
 *
 * Changes
 * -------
 * 08-Jul-2003 : Version 1 copied from JCommon (DG);
 *
 */

package org.jfree.workbook.date;

import java.io.Serializable;
import java.text.DateFormatSymbols;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar;

/**
 *  An abstract class that defines our requirements for manipulating dates,
 *  without tying down a particular implementation.
 *  <P>
 *  Requirement 1 : match at least what Excel does for dates;
 *  Requirement 2 : class is immutable;
 *  <P>
 *  Why not just use java.util.Date?  We will, when it makes sense.  At times,
 *  java.util.Date can be *too* precise - it represents an instant in time,
 *  accurate to 1/1000th of a second (with the date itself depending on the
 *  time-zone).  Sometimes we just want to represent a particular day (e.g. 21
 *  January 2015) without concerning ourselves about the time of day, or the
 *  time-zone, or anything else.  That's what we've defined SerialDate for.
 *  <P>
 *  You can call getInstance() to get a concrete subclass of SerialDate,
 *  without worrying about the exact implementation.
 *
 *  @author David Gilbert
 */
public abstract class SerialDate implements Serializable, MonthConstants {

    /** Date format symbols. */
    public static final DateFormatSymbols
        DATE_FORMAT_SYMBOLS = new SimpleDateFormat().getDateFormatSymbols();

    /** The serial number for 1 January 1900. */
    public static final int SERIAL_LOWER_BOUND = 2;

    /** The serial number for 31 December 9999. */
    public static final int SERIAL_UPPER_BOUND = 2958465;

    /** The lowest year value supported by this date format. */
    public static final int MINIMUM_YEAR_SUPPORTED = 1900;

    /** The highest year value supported by this date format. */
    public static final int MAXIMUM_YEAR_SUPPORTED = 9999;

    /** Useful constant for Monday. Equivalent to java.util.Calendar.MONDAY. */
    public static final int MONDAY = Calendar.MONDAY;

    /** Useful constant for Tuesday. Equivalent to java.util.Calendar.TUESDAY. */
    public static final int TUESDAY = Calendar.TUESDAY;

    /** Useful constant for Wednesday. Equivalent to java.util.Calendar.WEDNESDAY. */
    public static final int WEDNESDAY = Calendar.WEDNESDAY;

    /** Useful constant for Thrusday. Equivalent to java.util.Calendar.THURSDAY. */
    public static final int THURSDAY = Calendar.THURSDAY;

    /** Useful constant for Friday. Equivalent to java.util.Calendar.FRIDAY. */
    public static final int FRIDAY = Calendar.FRIDAY;

    /** Useful constant for Saturday. Equivalent to java.util.Calendar.SATURDAY. */
    public static final int SATURDAY = Calendar.SATURDAY;

    /** Useful constant for Sunday. Equivalent to java.util.Calendar.SUNDAY. */
    public static final int SUNDAY = Calendar.SUNDAY;

    /** The number of days in each month in non leap years. */
    public static final int[] LAST_DAY_OF_MONTH =
        {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

    /** The number of days in a (non-leap) year up to the end of each month. */
    public static final int[] AGGREGATE_DAYS_TO_END_OF_MONTH =
        {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};

    /** The number of days in a year up to the end of the preceding month. */
    public static final int[] AGGREGATE_DAYS_TO_END_OF_PRECEDING_MONTH =
        {0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};

    /** The number of days in a leap year up to the end of each month. */
    public static final int[] LEAP_YEAR_AGGREGATE_DAYS_TO_END_OF_MONTH =
        {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366};

    /** The number of days in a leap year up to the end of the preceding month. */
    public static final int[] LEAP_YEAR_AGGREGATE_DAYS_TO_END_OF_PRECEDING_MONTH =
        {0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366};

    /** A useful constant for referring to the first week in a month. */
    public static final int FIRST_WEEK_IN_MONTH = 1;

    /** A useful constant for referring to the second week in a month. */
    public static final int SECOND_WEEK_IN_MONTH = 2;

    /** A useful constant for referring to the third week in a month. */
    public static final int THIRD_WEEK_IN_MONTH = 3;

    /** A useful constant for referring to the fourth week in a month. */
    public static final int FOURTH_WEEK_IN_MONTH = 4;

    /** A useful constant for referring to the last week in a month. */
    public static final int LAST_WEEK_IN_MONTH = 0;

    /** Useful range constant. */
    public static final int INCLUDE_NONE = 0;

    /** Useful range constant. */
    public static final int INCLUDE_FIRST = 1;

    /** Useful range constant. */
    public static final int INCLUDE_SECOND = 2;

    /** Useful range constant. */
    public static final int INCLUDE_BOTH = 3;

    /** Useful constant for specifying a day of the week relative to a fixed date. */
    public static final int PRECEDING = -1;

    /** Useful constant for specifying a day of the week relative to a fixed date. */
    public static final int NEAREST = 0;

    /** Useful constant for specifying a day of the week relative to a fixed date. */
    public static final int FOLLOWING = 1;

    /** A description for the date. */
    private String description;

    /**
     * Returns true if the supplied integer code represents a valid day-of-the-week, and
     * false otherwise.
     *
     * @param code  the code being checked for validity.
     *
     * @return true if the supplied integer code represents a valid day-of-the-week, and false
     *              otherwise.
     */
    public static boolean isValidWeekdayCode(int code) {

        switch(code) {
            case SUNDAY: return true;
            case MONDAY: return true;
            case TUESDAY: return true;
            case WEDNESDAY: return true;
            case THURSDAY: return true;
            case FRIDAY: return true;
            case SATURDAY: return true;
            default: return false;
        }

    }

    /**
     * Converts the supplied string to a day of the week.
     *
     * @param s  a string representing the day of the week.
     *
     * @return <code>-1</code> if the string is not convertable, the day of the week otherwise.
     */
    public static int stringToWeekdayCode(String s) {

        String[] shortWeekdayNames = DATE_FORMAT_SYMBOLS.getShortWeekdays();
        String[] weekDayNames = DATE_FORMAT_SYMBOLS.getWeekdays();

        int result = -1;
        s = s.trim();
        for (int i = 0; i < weekDayNames.length; i++) {
            if (s.equals(shortWeekdayNames[i])) {
                result = i;
                break;
            }
            if (s.equals(weekDayNames[i])) {
                result = i;
                break;
            }
        }
        return result;

    }

    /**
     * Returns a string representing the supplied day-of-the-week.
     * <P>
     * Need to find a better approach.
     *
     * @param weekday  the day of the week.
     *
     * @return a string representing the supplied day-of-the-week.
     */
    public static String weekdayCodeToString(int weekday) {

        String[] weekdays = DATE_FORMAT_SYMBOLS.getWeekdays();
        return weekdays[weekday];

    }

    /**
     * Returns an array of month names.
     *
     * @return an array of month names.
     */
    public static String[] getMonths() {

        return getMonths(false);

    }

    /**
     * Returns an array of month names.
     *
     * @param shortened  a flag indicating that shortened month names should be returned.
     *
     * @return an array of month names.
     */
    public static String[] getMonths(boolean shortened) {

        if (shortened) {
            return DATE_FORMAT_SYMBOLS.getShortMonths();
        }
        else {
            return DATE_FORMAT_SYMBOLS.getMonths();
        }

    }

    /**
     * Returns true if the supplied integer code represents a valid month.
     *
     * @param code  the code being checked for validity.
     *
     * @return <code>true</code> if the supplied integer code represents a valid month.
     */
    public static boolean isValidMonthCode(int code) {

        switch(code) {
            case JANUARY: return true;
            case FEBRUARY: return true;
            case MARCH: return true;
            case APRIL: return true;
            case MAY: return true;
            case JUNE: return true;
            case JULY: return true;
            case AUGUST: return true;
            case SEPTEMBER: return true;
            case OCTOBER: return true;
            case NOVEMBER: return true;
            case DECEMBER: return true;
            default: return false;
        }

    }

    /**
     * Returns the quarter for the specified month.
     *
     * @param code  the month code (1-12).
     *
     * @return the quarter that the month belongs to.
     */
    public static int monthCodeToQuarter(int code) {

        switch(code) {
            case JANUARY: return 1;
            case FEBRUARY: return 1;
            case MARCH: return 1;
            case APRIL: return 2;
            case MAY: return 2;
            case JUNE: return 2;
            case JULY: return 3;
            case AUGUST: return 3;
            case SEPTEMBER: return 3;
            case OCTOBER: return 4;
            case NOVEMBER: return 4;
            case DECEMBER: return 4;
            default: throw new IllegalArgumentException(
                "SerialDate.monthCodeToQuarter: invalid month code.");
        }

    }