/* ===========================================================

 * JFreeChart : a free chart library for the Java(tm) platform

 * ===========================================================

 *

 * (C) Copyright 2000-2004, by Object Refinery Limited and Contributors.

 *

 * Project Info:  http://www.jfree.org/jfreechart/index.html

 *

 * 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.

 *

 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 

 * in the United States and other countries.]

 *

 * ---------

 * Hour.java

 * ---------

 * (C) Copyright 2001-2003, by Object Refinery Limited.

 *

 * Original Author:  David Gilbert (for Object Refinery Limited);

 * Contributor(s):   -;

 *

 * $Id: Hour.java,v 1.1 2004/08/31 15:34:17 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 Hour(Date) constructor (DG);

 * 26-Feb-2002 : Changed getStart(), getMiddle() and getEnd() methods to evaluate with reference

 *               to a particular time zone (DG);

 * 15-Mar-2002 : Changed API (DG);

 * 16-Apr-2002 : Fixed small time zone bug in constructor (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);

 * 21-Oct-2003 : Added hashCode() method, and new constructor for convenience (DG);

 *

 */



package org.jfree.data.time;



import java.io.Serializable;

import java.util.Calendar;

import java.util.Date;

import java.util.TimeZone;



/**

 * Represents an hour in a specific day.

 * <P>

 * This class is immutable, which is a requirement for all {@link RegularTimePeriod} subclasses.

 *

 */

public class Hour extends RegularTimePeriod implements Serializable {



    /** Useful constant for the first hour in the day. */

    public static final int FIRST_HOUR_IN_DAY = 0;



    /** Useful constant for the last hour in the day. */

    public static final int LAST_HOUR_IN_DAY = 23;



    /** The day. */

    private Day day;



    /** The hour. */

    private int hour;



    /**

     * Constructs a new Hour, based on the system date/time.

     */

    public Hour() {



        this(new Date());



    }



    /**

     * Constructs a new Hour.

     *

     * @param hour  the hour (in the range 0 to 23).

     * @param day  the day.

     */

    public Hour(final int hour, final Day day) {



        this.hour = hour;

        this.day = day;



    }



    /**

     * Creates a new hour.

     * 

     * @param hour  the hour (0-23).

     * @param day  the day (1-31).

     * @param month  the month (1-12).

     * @param year  the year (1900-9999).

     */

    public Hour(final int hour, final int day, final int month, final int year) {

        this(hour, new Day(day, month, year));

    }

    

    /**

     * Constructs a new Hour, based on the supplied date/time.

     *

     * @param time  the date-time.

     */

    public Hour(final Date time) {



        this(time, RegularTimePeriod.DEFAULT_TIME_ZONE);



    }



    /**

     * Constructs a new Hour, based on the supplied date/time evaluated in the

     * specified time zone.

     *

     * @param time  the date-time.

     * @param zone  the time zone.

     */

    public Hour(final Date time, final TimeZone zone) {



        final Calendar calendar = Calendar.getInstance(zone);

        calendar.setTime(time);

        final int hour = calendar.get(Calendar.HOUR_OF_DAY);

        this.hour = hour;

        this.day = new Day(time, zone);



    }



    /**

     * Returns the hour.

     *

     * @return the hour.

     */

    public int getHour() {

        return this.hour;

    }



    /**

     * Returns the day in which this hour falls.

     *

     * @return the day.

     */

    public Day getDay() {

        return this.day;

    }



    /**

     * Returns the year in which this hour falls.

     *

     * @return the year.

     */

    public int getYear() {

        return this.day.getYear();

    }



    /**

     * Returns the month in which this hour falls.

     *

     * @return the month.

     */

    public int getMonth() {

        return this.day.getMonth();

    }



    /**

     * Returns the day-of-the-month in which this hour falls.

     *

     * @return the day-of-the-month.

     */

    public int getDayOfMonth() {

        return this.day.getDayOfMonth();

    }



    /**

     * Returns the hour preceding this one.

     *

     * @return the hour preceding this one.

     */

    public RegularTimePeriod previous() {



        final Hour result;

        if (this.hour != FIRST_HOUR_IN_DAY) {

            result = new Hour(this.hour - 1, this.day);

        }

        else { // we are at the first hour in the day...

            final Day prevDay = (Day) this.day.previous();

            if (prevDay != null) {

                result = new Hour(LAST_HOUR_IN_DAY, prevDay);

            }

            else {

                result = null;

            }

        }

        return result;



    }



    /**

     * Returns the hour following this one.

     *

     * @return the hour following this one.

     */

    public RegularTimePeriod next() {



        final Hour result;

        if (this.hour != LAST_HOUR_IN_DAY) {

            result = new Hour(this.hour + 1, this.day);

        }

        else { // we are at the last hour in the day...

            final Day nextDay = (Day) this.day.next();

            if (nextDay != null) {

                result = new Hour(FIRST_HOUR_IN_DAY, nextDay);

            }

            else {

                result = null;

            }

        }

        return result;



    }



    /**

     * Returns a serial index number for the hour.

     *

     * @return The serial index number.

     */

    public long getSerialIndex() {

        return this.day.getSerialIndex() * 24L + this.hour;

    }



    /**

     * Returns the first millisecond of the hour.

     *

     * @param calendar  the calendar/timezone.

     *

     * @return the first millisecond.

     */

    public long getFirstMillisecond(final Calendar calendar) {



        final int year = this.day.getYear();

        final int month = this.day.getMonth() - 1;

        final int day = this.day.getDayOfMonth();



        calendar.set(year, month, day, this.hour, 0, 0);

        calendar.set(Calendar.MILLISECOND, 0);



        return calendar.getTime().getTime();



    }



    /**

     * Returns the last millisecond of the hour.

     *

     * @param calendar  the calendar/timezone.

     *

     * @return the last millisecond.

     */

    public long getLastMillisecond(final Calendar calendar) {



        final int year = this.day.getYear();

        final int month = this.day.getMonth() - 1;

        final int day = this.day.getDayOfMonth();



        calendar.set(year, month, day, this.hour, 59, 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 an Hour object

     * representing the same hour as this instance.

     *

     * @param object  the object to compare.

     *

     * @return <code>true</code> if the hour and day value of the object

     *      is the same as this.

     */

    public boolean equals(final Object object) {

        if (object instanceof Hour) {

            final Hour h = (Hour) object;

            return ((this.hour == h.getHour()) && (this.day.equals(h.getDay())));

        }

        else {

            return false;

        }

    }



    /**

     * Returns a hash code for this object instance.

     * <p>

     * The approach described by Joshua Bloch in "Effective Java" has been used here:

     * <p>

     * <code>http://developer.java.sun.com/developer/Books/effectivejava/Chapter3.pdf</code>

     * 

     * @return A hash code.

     */

    public int hashCode() {

        int result = 17;

        result = 37 * result + this.hour;

        result = 37 * result + this.day.hashCode();

        return result;

    }



    /**

     * Returns an integer indicating the order of this Hour object relative to

     * the specified object:

     *

     * negative == before, zero == same, positive == after.

     *

     * @param o1  the object to compare.

     *

     * @return negative == before, zero == same, positive == after.

     */

    public int compareTo(final Object o1) {



        int result;



        // CASE 1 : Comparing to another Hour object

        // -----------------------------------------

        if (o1 instanceof Hour) {

            final Hour h = (Hour) o1;

            result = getDay().compareTo(h.getDay());

            if (result == 0) {

                result = this.hour - h.getHour();

            }

        }



        // 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 an Hour instance by parsing a string.  The string is assumed to

     * be in the format "YYYY-MM-DD HH", perhaps with leading or trailing

     * whitespace.

     *

     * @param s  the hour string to parse.

     *

     * @return <code>null</code> if the string is not parseable, the hour otherwise.

     */

    public static Hour parseHour(String s) {



        Hour result = null;

        s = s.trim();



        final String daystr = s.substring(0, Math.min(10, s.length()));

        final Day day = Day.parseDay(daystr);

        if (day != null) {

            String hourstr = s.substring(Math.min(daystr.length() + 1, s.length()),

                                         s.length());

            hourstr = hourstr.trim();

            final int hour = Integer.parseInt(hourstr);

            // if the hour is 0 - 23 then create an hour

            if ((hour >= FIRST_HOUR_IN_DAY) && (hour <= LAST_HOUR_IN_DAY)) {

                result = new Hour(hour, day);

            }

        }



        return result;



    }



}

