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Java example source code file (Hours.java)

This example Java source code file (Hours.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

duration, eight, five, four, hours, localtime, max_value, min_value, one, seven, six, three, two, zero

The Hours.java Java example source code

/*
 *  Copyright 2001-2010 Stephen Colebourne
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.joda.time;

import org.joda.convert.FromString;
import org.joda.convert.ToString;
import org.joda.time.base.BaseSingleFieldPeriod;
import org.joda.time.field.FieldUtils;
import org.joda.time.format.ISOPeriodFormat;
import org.joda.time.format.PeriodFormatter;

/**
 * An immutable time period representing a number of hours.
 * <p>
 * <code>Hours is an immutable period that can only store hours.
 * It does not store years, months or minutes for example. As such it is a
 * type-safe way of representing a number of hours in an application.
 * <p>
 * The number of hours is set in the constructor, and may be queried using
 * <code>getHours(). Basic mathematical operations are provided -
 * <code>plus(), minus(), multipliedBy() and
 * <code>dividedBy().
 * <p>
 * <code>Hours is thread-safe and immutable.
 *
 * @author Stephen Colebourne
 * @since 1.4
 */
public final class Hours extends BaseSingleFieldPeriod {

    /** Constant representing zero hours. */
    public static final Hours ZERO = new Hours(0);
    /** Constant representing one hour. */
    public static final Hours ONE = new Hours(1);
    /** Constant representing two hours. */
    public static final Hours TWO = new Hours(2);
    /** Constant representing three hours. */
    public static final Hours THREE = new Hours(3);
    /** Constant representing four hours. */
    public static final Hours FOUR = new Hours(4);
    /** Constant representing five hours. */
    public static final Hours FIVE = new Hours(5);
    /** Constant representing six hours. */
    public static final Hours SIX = new Hours(6);
    /** Constant representing seven hours. */
    public static final Hours SEVEN = new Hours(7);
    /** Constant representing eight hours. */
    public static final Hours EIGHT = new Hours(8);
    /** Constant representing the maximum number of hours that can be stored in this object. */
    public static final Hours MAX_VALUE = new Hours(Integer.MAX_VALUE);
    /** Constant representing the minimum number of hours that can be stored in this object. */
    public static final Hours MIN_VALUE = new Hours(Integer.MIN_VALUE);

    /** The paser to use for this class. */
    private static final PeriodFormatter PARSER = ISOPeriodFormat.standard().withParseType(PeriodType.hours());
    /** Serialization version. */
    private static final long serialVersionUID = 87525275727380864L;

    //-----------------------------------------------------------------------
    /**
     * Obtains an instance of <code>Hours that may be cached.
     * <code>Hours is immutable, so instances can be cached and shared.
     * This factory method provides access to shared instances.
     *
     * @param hours  the number of hours to obtain an instance for
     * @return the instance of Hours
     */
    public static Hours hours(int hours) {
        switch (hours) {
            case 0:
                return ZERO;
            case 1:
                return ONE;
            case 2:
                return TWO;
            case 3:
                return THREE;
            case 4:
                return FOUR;
            case 5:
                return FIVE;
            case 6:
                return SIX;
            case 7:
                return SEVEN;
            case 8:
                return EIGHT;
            case Integer.MAX_VALUE:
                return MAX_VALUE;
            case Integer.MIN_VALUE:
                return MIN_VALUE;
            default:
                return new Hours(hours);
        }
    }

    //-----------------------------------------------------------------------
    /**
     * Creates a <code>Hours representing the number of whole hours
     * between the two specified datetimes.
     *
     * @param start  the start instant, must not be null
     * @param end  the end instant, must not be null
     * @return the period in hours
     * @throws IllegalArgumentException if the instants are null or invalid
     */
    public static Hours hoursBetween(ReadableInstant start, ReadableInstant end) {
        int amount = BaseSingleFieldPeriod.between(start, end, DurationFieldType.hours());
        return Hours.hours(amount);
    }

    /**
     * Creates a <code>Hours representing the number of whole hours
     * between the two specified partial datetimes.
     * <p>
     * The two partials must contain the same fields, for example you can specify
     * two <code>LocalTime objects.
     *
     * @param start  the start partial date, must not be null
     * @param end  the end partial date, must not be null
     * @return the period in hours
     * @throws IllegalArgumentException if the partials are null or invalid
     */
    public static Hours hoursBetween(ReadablePartial start, ReadablePartial end) {
        if (start instanceof LocalTime && end instanceof LocalTime)   {
            Chronology chrono = DateTimeUtils.getChronology(start.getChronology());
            int hours = chrono.hours().getDifference(
                    ((LocalTime) end).getLocalMillis(), ((LocalTime) start).getLocalMillis());
            return Hours.hours(hours);
        }
        int amount = BaseSingleFieldPeriod.between(start, end, ZERO);
        return Hours.hours(amount);
    }

    /**
     * Creates a <code>Hours representing the number of whole hours
     * in the specified interval.
     *
     * @param interval  the interval to extract hours from, null returns zero
     * @return the period in hours
     * @throws IllegalArgumentException if the partials are null or invalid
     */
    public static Hours hoursIn(ReadableInterval interval) {
        if (interval == null)   {
            return Hours.ZERO;
        }
        int amount = BaseSingleFieldPeriod.between(interval.getStart(), interval.getEnd(), DurationFieldType.hours());
        return Hours.hours(amount);
    }

    /**
     * Creates a new <code>Hours representing the number of complete
     * standard length hours in the specified period.
     * <p>
     * This factory method converts all fields from the period to hours using standardised
     * durations for each field. Only those fields which have a precise duration in
     * the ISO UTC chronology can be converted.
     * <ul>
     * <li>One week consists of 7 days.
     * <li>One day consists of 24 hours.
     * <li>One hour consists of 60 minutes.
     * <li>One minute consists of 60 seconds.
     * <li>One second consists of 1000 milliseconds.
     * </ul>
     * Months and Years are imprecise and periods containing these values cannot be converted.
     *
     * @param period  the period to get the number of hours from, null returns zero
     * @return the period in hours
     * @throws IllegalArgumentException if the period contains imprecise duration values
     */
    public static Hours standardHoursIn(ReadablePeriod period) {
        int amount = BaseSingleFieldPeriod.standardPeriodIn(period, DateTimeConstants.MILLIS_PER_HOUR);
        return Hours.hours(amount);
    }

    /**
     * Creates a new <code>Hours by parsing a string in the ISO8601 format 'PTnH'.
     * <p>
     * The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the
     * hours component may be non-zero. If any other component is non-zero, an exception
     * will be thrown.
     *
     * @param periodStr  the period string, null returns zero
     * @return the period in hours
     * @throws IllegalArgumentException if the string format is invalid
     */
    @FromString
    public static Hours parseHours(String periodStr) {
        if (periodStr == null) {
            return Hours.ZERO;
        }
        Period p = PARSER.parsePeriod(periodStr);
        return Hours.hours(p.getHours());
    }

    //-----------------------------------------------------------------------
    /**
     * Creates a new instance representing a number of hours.
     * You should consider using the factory method {@link #hours(int)}
     * instead of the constructor.
     *
     * @param hours  the number of hours to represent
     */
    private Hours(int hours) {
        super(hours);
    }

    /**
     * Resolves singletons.
     * 
     * @return the singleton instance
     */
    private Object readResolve() {
        return Hours.hours(getValue());
    }

    //-----------------------------------------------------------------------
    /**
     * Gets the duration field type, which is <code>hours.
     *
     * @return the period type
     */
    public DurationFieldType getFieldType() {
        return DurationFieldType.hours();
    }

    /**
     * Gets the period type, which is <code>hours.
     *
     * @return the period type
     */
    public PeriodType getPeriodType() {
        return PeriodType.hours();
    }

    //-----------------------------------------------------------------------
    /**
     * Converts this period in hours to a period in weeks assuming a
     * 7 day week and 24 hour day.
     * <p>
     * This method allows you to convert between different types of period.
     * However to achieve this it makes the assumption that all weeks are 7 days
     * long and all days are 24 hours long.
     * This is not true when daylight savings time is considered, and may also
     * not be true for some unusual chronologies. However, it is included as it
     * is a useful operation for many applications and business rules.
     * 
     * @return a period representing the number of whole weeks for this number of hours
     */
    public Weeks toStandardWeeks() {
        return Weeks.weeks(getValue() / DateTimeConstants.HOURS_PER_WEEK);
    }

    /**
     * Converts this period in hours to a period in days assuming a
     * 24 hour day.
     * <p>
     * This method allows you to convert between different types of period.
     * However to achieve this it makes the assumption that all days are 24 hours long.
     * This is not true when daylight savings time is considered, and may also
     * not be true for some unusual chronologies. However, it is included as it
     * is a useful operation for many applications and business rules.
     * 
     * @return a period representing the number of whole days for this number of hours
     */
    public Days toStandardDays() {
        return Days.days(getValue() / DateTimeConstants.HOURS_PER_DAY);
    }

    /**
     * Converts this period in hours to a period in minutes assuming a
     * 60 minute hour.
     * <p>
     * This method allows you to convert between different types of period.
     * However to achieve this it makes the assumption that all hours are 60 minutes long.
     * This may not be true for some unusual chronologies. However, it is included
     * as it is a useful operation for many applications and business rules.
     * 
     * @return a period representing the number of minutes for this number of hours
     * @throws ArithmeticException if the number of minutes is too large to be represented
     */
    public Minutes toStandardMinutes() {
        return Minutes.minutes(FieldUtils.safeMultiply(getValue(), DateTimeConstants.MINUTES_PER_HOUR));
    }

    /**
     * Converts this period in hours to a period in seconds assuming a
     * 60 minute hour and 60 second minute.
     * <p>
     * This method allows you to convert between different types of period.
     * However to achieve this it makes the assumption that all hours are
     * 60 minutes long and all minutes are 60 seconds long.
     * This may not be true for some unusual chronologies. However, it is included
     * as it is a useful operation for many applications and business rules.
     * 
     * @return a period representing the number of seconds for this number of hours
     * @throws ArithmeticException if the number of seconds is too large to be represented
     */
    public Seconds toStandardSeconds() {
        return Seconds.seconds(FieldUtils.safeMultiply(getValue(), DateTimeConstants.SECONDS_PER_HOUR));
    }

    //-----------------------------------------------------------------------
    /**
     * Converts this period in hours to a duration in milliseconds assuming a
     * 60 minute hour and 60 second minute.
     * <p>
     * This method allows you to convert from a period to a duration.
     * However to achieve this it makes the assumption that all hours are
     * 60 minutes and all minutes are 60 seconds. This might not be true for an
     * unusual chronology, for example one that takes leap seconds into account.
     * However, the method is included as it is a useful operation for many
     * applications and business rules.
     *
     * @return a duration equivalent to this number of hours
     */
    public Duration toStandardDuration() {
        long hours = getValue();  // assign to a long
        return new Duration(hours * DateTimeConstants.MILLIS_PER_HOUR);
    }

    //-----------------------------------------------------------------------
    /**
     * Gets the number of hours that this period represents.
     *
     * @return the number of hours in the period
     */
    public int getHours() {
        return getValue();
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a new instance with the specified number of hours added.
     * <p>
     * This instance is immutable and unaffected by this method call.
     *
     * @param hours  the amount of hours to add, may be negative
     * @return the new period plus the specified number of hours
     * @throws ArithmeticException if the result overflows an int
     */
    public Hours plus(int hours) {
        if (hours == 0) {
            return this;
        }
        return Hours.hours(FieldUtils.safeAdd(getValue(), hours));
    }

    /**
     * Returns a new instance with the specified number of hours added.
     * <p>
     * This instance is immutable and unaffected by this method call.
     *
     * @param hours  the amount of hours to add, may be negative, null means zero
     * @return the new period plus the specified number of hours
     * @throws ArithmeticException if the result overflows an int
     */
    public Hours plus(Hours hours) {
        if (hours == null) {
            return this;
        }
        return plus(hours.getValue());
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a new instance with the specified number of hours taken away.
     * <p>
     * This instance is immutable and unaffected by this method call.
     *
     * @param hours  the amount of hours to take away, may be negative
     * @return the new period minus the specified number of hours
     * @throws ArithmeticException if the result overflows an int
     */
    public Hours minus(int hours) {
        return plus(FieldUtils.safeNegate(hours));
    }

    /**
     * Returns a new instance with the specified number of hours taken away.
     * <p>
     * This instance is immutable and unaffected by this method call.
     *
     * @param hours  the amount of hours to take away, may be negative, null means zero
     * @return the new period minus the specified number of hours
     * @throws ArithmeticException if the result overflows an int
     */
    public Hours minus(Hours hours) {
        if (hours == null) {
            return this;
        }
        return minus(hours.getValue());
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a new instance with the hours multiplied by the specified scalar.
     * <p>
     * This instance is immutable and unaffected by this method call.
     *
     * @param scalar  the amount to multiply by, may be negative
     * @return the new period multiplied by the specified scalar
     * @throws ArithmeticException if the result overflows an int
     */
    public Hours multipliedBy(int scalar) {
        return Hours.hours(FieldUtils.safeMultiply(getValue(), scalar));
    }

    /**
     * Returns a new instance with the hours divided by the specified divisor.
     * The calculation uses integer division, thus 3 divided by 2 is 1.
     * <p>
     * This instance is immutable and unaffected by this method call.
     *
     * @param divisor  the amount to divide by, may be negative
     * @return the new period divided by the specified divisor
     * @throws ArithmeticException if the divisor is zero
     */
    public Hours dividedBy(int divisor) {
        if (divisor == 1) {
            return this;
        }
        return Hours.hours(getValue() / divisor);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a new instance with the hours value negated.
     *
     * @return the new period with a negated value
     * @throws ArithmeticException if the result overflows an int
     */
    public Hours negated() {
        return Hours.hours(FieldUtils.safeNegate(getValue()));
    }

    //-----------------------------------------------------------------------
    /**
     * Is this hours instance greater than the specified number of hours.
     *
     * @param other  the other period, null means zero
     * @return true if this hours instance is greater than the specified one
     */
    public boolean isGreaterThan(Hours other) {
        if (other == null) {
            return getValue() > 0;
        }
        return getValue() > other.getValue();
    }

    /**
     * Is this hours instance less than the specified number of hours.
     *
     * @param other  the other period, null means zero
     * @return true if this hours instance is less than the specified one
     */
    public boolean isLessThan(Hours other) {
        if (other == null) {
            return getValue() < 0;
        }
        return getValue() < other.getValue();
    }

    //-----------------------------------------------------------------------
    /**
     * Gets this instance as a String in the ISO8601 duration format.
     * <p>
     * For example, "PT4H" represents 4 hours.
     *
     * @return the value as an ISO8601 string
     */
    @ToString
    public String toString() {
        return "PT" + String.valueOf(getValue()) + "H";
    }

}

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