minute.java

Web图形化的Java库

/* ======================================
 * JFreeChart : a free Java chart library
 * ======================================
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 * Project Lead:  David Gilbert ([e-mail]);
 *
 * (C) Copyright 2000-2003, by Object Refinery Limited and Contributors.
 *
 * 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.
 *
 * -----------
 * Minute.java
 * -----------
 * (C) Copyright 2001-2003, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: Minute.java,v 1.3 2003/06/04 22:59:01 mungady Exp $
 *
 * Changes
 * -------
 * 11-Oct-2001 : Version 1 (DG);
 * 18-Dec-2001 : Changed order of parameters in constructor (DG);
 * 19-Dec-2001 : Added a new constructor as suggested by Paul English (DG);
 * 14-Feb-2002 : Fixed bug in Minute(Date) constructor, and changed the range to start from zero
 *               instead of one (DG);
 * 26-Feb-2002 : Changed getStart(), getMiddle() and getEnd() methods to evaluate with reference
 *               to a particular time zone (DG);
 * 13-Mar-2002 : Added parseMinute() method (DG);
 * 19-Mar-2002 : Changed API, the minute is now defined in relation to an Hour (DG);
 * 10-Sep-2002 : Added getSerialIndex() method (DG);
 * 07-Oct-2002 : Fixed errors reported by Checkstyle (DG);
 * 10-Jan-2003 : Changed base class and method names (DG);
 * 13-Mar-2003 : Moved to com.jrefinery.data.time package and implemented Serializable (DG);
 *
 */

package org.jfree.data.time;

import java.io.Serializable;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

/**
 * Represents a minute.
 * <P>
 * This class is immutable, which is a requirement for all {@link RegularTimePeriod} subclasses.
 *
 * @author David Gilbert
 */
public class Minute extends RegularTimePeriod implements Serializable {

    /** Useful constant for the first minute in a day. */
    public static final int FIRST_MINUTE_IN_HOUR = 0;

    /** Useful constant for the last minute in a day. */
    public static final int LAST_MINUTE_IN_HOUR = 59;

    /** The hour in which the minute falls. */
    private Hour hour;

    /** The minute. */
    private int minute;

    /**
     * Constructs a new Minute, based on the system date/time.
     */
    public Minute() {

        this(new Date());

    }

    /**
     * Constructs a new Minute.
     *
     * @param minute  the minute (0 to 59).
     * @param hour  the hour.
     */
    public Minute(int minute, Hour hour) {

        this.minute = minute;
        this.hour = hour;

    }

    /**
     * Constructs a new Minute, based on the supplied date/time.
     *
     * @param time  the time.
     */
    public Minute(Date time) {
        this(time, RegularTimePeriod.DEFAULT_TIME_ZONE);
    }

    /**
     * Constructs a new Minute, based on the supplied date/time and timezone.
     *
     * @param time  the time.
     * @param zone  the time zone.
     */
    public Minute(Date time, TimeZone zone) {

        Calendar calendar = Calendar.getInstance(zone);
        calendar.setTime(time);
        int min = calendar.get(Calendar.MINUTE);
        this.minute = min;
        this.hour = new Hour(time, zone);

    }

    /**
     * Returns the hour.
     *
     * @return the hour.
     */
    public Hour getHour() {
        return this.hour;
    }

    /**
     * Returns the minute.
     *
     * @return the minute.
     */
    public int getMinute() {
        return this.minute;
    }

    /**
     * Returns the minute preceding this one.
     *
     * @return the minute preceding this one.
     */
    public RegularTimePeriod previous() {

        Minute result;
        if (this.minute != FIRST_MINUTE_IN_HOUR) {
            result = new Minute(minute - 1, this.hour);
        }
        else { // we are at the first minute in the hour...
            Hour prevHour = (Hour) hour.previous();
            if (prevHour != null) {
                result = new Minute(LAST_MINUTE_IN_HOUR, prevHour);
            }
            else {
                result = null;
            }
        }
        return result;

    }

    /**
     * Returns the minute following this one.
     *
     * @return the minute following this one.
     */
    public RegularTimePeriod next() {

        Minute result;
        if (this.minute != LAST_MINUTE_IN_HOUR) {
            result = new Minute(minute + 1, this.hour);
        }
        else { // we are at the last minute in the hour...
            Hour nextHour = (Hour) hour.next();
            if (nextHour != null) {
                result = new Minute(FIRST_MINUTE_IN_HOUR, nextHour);
            }
            else {
                result = null;
            }
        }
        return result;

    }

    /**
     * Returns a serial index number for the minute.
     *
     * @return the serial index number.
     */
    public long getSerialIndex() {
        return this.hour.getSerialIndex() * 60L + this.minute;
    }

    /**
     * Returns the first millisecond of the minute.
     *
     * @param calendar  the calendar and timezone.
     *
     * @return the first millisecond.
     */
    public long getFirstMillisecond(Calendar calendar) {

        int year = this.hour.getDay().getYear();
        int month = this.hour.getDay().getMonth() - 1;
        int day = this.hour.getDay().getDayOfMonth();

        calendar.clear();
        calendar.set(year, month, day, hour.getHour(), this.minute, 0);
        calendar.set(Calendar.MILLISECOND, 0);

        return calendar.getTime().getTime();

    }

    /**
     * Returns the last millisecond of the minute.
     *
     * @param calendar  the calendar and timezone.
     *
     * @return the last millisecond.
     */
    public long getLastMillisecond(Calendar calendar) {

        int year = this.hour.getDay().getYear();
        int month = this.hour.getDay().getMonth() - 1;
        int day = this.hour.getDay().getDayOfMonth();

        calendar.clear();
        calendar.set(year, month, day, hour.getHour(), this.minute, 59);
        calendar.set(Calendar.MILLISECOND, 999);

        return calendar.getTime().getTime();

    }

    /**
     * Tests the equality of this object against an arbitrary Object.
     * <P>
     * This method will return true ONLY if the object is a Minute object
     * representing the same minute as this instance.
     *
     * @param object  the object to compare.
     *
     * @return <code>true</code> if the minute and hour value of this and the
     *      object are the same.
     */
    public boolean equals(Object object) {
        if (object instanceof Minute) {
            Minute m = (Minute) object;
            return ((this.minute == m.getMinute()) && (this.hour.equals(m.getHour())));
        }
        else {
            return false;
        }
    }

    /**
     * Returns an integer indicating the order of this Minute object relative
     * to the specified object:
     *
     * negative == before, zero == same, positive == after.
     *
     * @param o1  object to compare.
     *
     * @return negative == before, zero == same, positive == after.
     */
    public int compareTo(Object o1) {

        int result;

        // CASE 1 : Comparing to another Minute object
        // -------------------------------------------
        if (o1 instanceof Minute) {
            Minute m = (Minute) o1;
            result = getHour().compareTo(m.getHour());
            if (result == 0) {
                result = this.minute - m.getMinute();
            }
        }

        // CASE 2 : Comparing to another TimePeriod object
        // -----------------------------------------------
        else if (o1 instanceof RegularTimePeriod) {
            // more difficult case - evaluate later...
            result = 0;
        }

        // CASE 3 : Comparing to a non-TimePeriod object
        // ---------------------------------------------
        else {
            // consider time periods to be ordered after general objects
            result = 1;
        }

        return result;

    }

    /**
     * Creates a Minute instance by parsing a string.  The string is assumed to
     * be in the format "YYYY-MM-DD HH:MM", perhaps with leading or trailing
     * whitespace.
     *
     * @param s  the minute string to parse.
     *
     * @return <code>null</code>, if the string is not parseable, the minute
     *      otherwise.
     */
    public static Minute parseMinute(String s) {

        Minute result = null;
        s = s.trim();

        String daystr = s.substring(0, Math.min(10, s.length()));
        Day day = Day.parseDay(daystr);
        if (day != null) {
            String hmstr = s.substring(Math.min(daystr.length() + 1, s.length()), s.length());
            hmstr = hmstr.trim();

            String hourstr = hmstr.substring(0, Math.min(2, hmstr.length()));
            int hour = Integer.parseInt(hourstr);

            if ((hour >= 0) && (hour <= 23)) {
                String minstr = hmstr.substring(Math.min(hourstr.length() + 1, hmstr.length()),
                                                hmstr.length());
                int minute = Integer.parseInt(minstr);
                if ((minute >= 0) && (minute <= 59)) {
                    result = new Minute(minute, new Hour(hour, day));
                }
            }
        }

        return result;

    }

}