http://www.joda.org/joda-time/: Date and time library to replace JDK date handling (Joda.org) 
/*
 *  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 weeks.


Weeks is an immutable period that can only store weeks.
It does not store years, months or hours for example. As such it is a
type-safe way of representing a number of weeks in an application.


The number of weeks is set in the constructor, and may be queried using
getWeeks(). Basic mathematical operations are provided -
plus(), minus(), multipliedBy() and
dividedBy().


Weeks is thread-safe and immutable.

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

    
Constant representing zero weeks. 
/** Constant representing zero weeks. */
    public static final Weeks ZERO = new Weeks(0);
    
Constant representing one week. 
/** Constant representing one week. */
    public static final Weeks ONE = new Weeks(1);
    
Constant representing two weeks. 
/** Constant representing two weeks. */
    public static final Weeks TWO = new Weeks(2);
    
Constant representing three weeks. 
/** Constant representing three weeks. */
    public static final Weeks THREE = new Weeks(3);
    
Constant representing the maximum number of weeks that can be stored in this object. 
/** Constant representing the maximum number of weeks that can be stored in this object. */
    public static final Weeks MAX_VALUE = new Weeks(Integer.MAX_VALUE);
    
Constant representing the minimum number of weeks that can be stored in this object. 
/** Constant representing the minimum number of weeks that can be stored in this object. */
    public static final Weeks MIN_VALUE = new Weeks(Integer.MIN_VALUE);

    
The parser to use for this class. 
/** The parser to use for this class. */
    private static final PeriodFormatter PARSER = ISOPeriodFormat.standard().withParseType(PeriodType.weeks());
    
Serialization version. 
/** Serialization version. */
    private static final long serialVersionUID = 87525275727380866L;

    //-----------------------------------------------------------------------
    
Obtains an instance of Weeks that may be cached.
Weeks is immutable, so instances can be cached and shared.
This factory method provides access to shared instances.

Params:
  • weeks –  the number of weeks to obtain an instance for
Returns:the instance of Weeks
/**
     * Obtains an instance of <code>Weeks</code> that may be cached.
     * <code>Weeks</code> is immutable, so instances can be cached and shared.
     * This factory method provides access to shared instances.
     *
     * @param weeks  the number of weeks to obtain an instance for
     * @return the instance of Weeks
     */
    public static Weeks weeks(int weeks) {
        switch (weeks) {
            case 0:
                return ZERO;
            case 1:
                return ONE;
            case 2:
                return TWO;
            case 3:
                return THREE;
            case Integer.MAX_VALUE:
                return MAX_VALUE;
            case Integer.MIN_VALUE:
                return MIN_VALUE;
            default:
                return new Weeks(weeks);
        }
    }

    //-----------------------------------------------------------------------
    
Creates a Weeks representing the number of whole weeks
between the two specified datetimes.

Params:
  • start –  the start instant, must not be null
  • end –  the end instant, must not be null
Throws:
Returns:the period in weeks
/**
     * Creates a <code>Weeks</code> representing the number of whole weeks
     * 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 weeks
     * @throws IllegalArgumentException if the instants are null or invalid
     */
    public static Weeks weeksBetween(ReadableInstant start, ReadableInstant end) {
        int amount = BaseSingleFieldPeriod.between(start, end, DurationFieldType.weeks());
        return Weeks.weeks(amount);
    }

    
Creates a Weeks representing the number of whole weeks
between the two specified partial datetimes.


The two partials must contain the same fields, for example you can specify
two LocalDate objects.

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

    
Creates a Weeks representing the number of whole weeks
in the specified interval.

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

    
Creates a new Weeks representing the number of complete
standard length weeks in the specified period.


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.

    

  • One week consists of 7 days.

  • One day consists of 24 hours.

  • One hour consists of 60 minutes.

  • One minute consists of 60 weeks.

  • One second consists of 1000 milliseconds.


Months and Years are imprecise and periods containing these values cannot be converted.

Params:
  • period –  the period to get the number of hours from, null returns zero
Throws:
Returns:the period in weeks
/**
     * Creates a new <code>Weeks</code> representing the number of complete
     * standard length weeks 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 weeks.
     * <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 weeks
     * @throws IllegalArgumentException if the period contains imprecise duration values
     */
    public static Weeks standardWeeksIn(ReadablePeriod period) {
        int amount = BaseSingleFieldPeriod.standardPeriodIn(period, DateTimeConstants.MILLIS_PER_WEEK);
        return Weeks.weeks(amount);
    }

    
Creates a new Weeks by parsing a string in the ISO8601 format 'PnW'.


The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the
weeks component may be non-zero. If any other component is non-zero, an exception
will be thrown.

Params:
  • periodStr –  the period string, null returns zero
Throws:
Returns:the period in weeks
/**
     * Creates a new <code>Weeks</code> by parsing a string in the ISO8601 format 'PnW'.
     * <p>
     * The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the
     * weeks 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 weeks
     * @throws IllegalArgumentException if the string format is invalid
     */
    @FromString
    public static Weeks parseWeeks(String periodStr) {
        if (periodStr == null) {
            return Weeks.ZERO;
        }
        Period p = PARSER.parsePeriod(periodStr);
        return Weeks.weeks(p.getWeeks());
    }

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

    
Resolves singletons.

Returns:the singleton instance
/**
     * Resolves singletons.
     * 
     * @return the singleton instance
     */
    private Object readResolve() {
        return Weeks.weeks(getValue());
    }

    //-----------------------------------------------------------------------
    
Gets the duration field type, which is weeks.

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

    
Gets the period type, which is weeks.

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

    //-----------------------------------------------------------------------
    
Converts this period in weeks to a period in days assuming a
7 day week.


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.
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.

Throws:
Returns:a period representing the number of days for this number of weeks
/**
     * Converts this period in weeks to a period in days assuming a
     * 7 day week.
     * <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.
     * 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 days for this number of weeks
     * @throws ArithmeticException if the number of days is too large to be represented
     */
    public Days toStandardDays() {
        return Days.days(FieldUtils.safeMultiply(getValue(), DateTimeConstants.DAYS_PER_WEEK));
    }

    
Converts this period in weeks to a period in hours assuming a
7 day week and 24 hour day.


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 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.

Throws:
Returns:a period representing the number of hours for this number of weeks
/**
     * Converts this period in weeks to a period in hours 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 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 hours for this number of weeks
     * @throws ArithmeticException if the number of hours is too large to be represented
     */
    public Hours toStandardHours() {
        return Hours.hours(FieldUtils.safeMultiply(getValue(), DateTimeConstants.HOURS_PER_WEEK));
    }

    
Converts this period in weeks to a period in minutes assuming a
7 day week, 24 hour day and 60 minute hour.


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, all days are 24 hours long and all hours are 60 minutes long.
This is not true when daylight savings 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.

Throws:
Returns:a period representing the number of minutes for this number of weeks
/**
     * Converts this period in weeks to a period in minutes assuming a
     * 7 day week, 24 hour day and 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 weeks are
     * 7 days long, all days are 24 hours long and all hours are 60 minutes long.
     * This is not true when daylight savings 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 minutes for this number of weeks
     * @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_WEEK));
    }

    
Converts this period in weeks to a period in seconds assuming a
7 day week, 24 hour day, 60 minute hour and 60 second minute.


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, all days are 24 hours long, all hours are 60 minutes long
and all minutes are 60 seconds long.
This is not true when daylight savings 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.

Throws:
Returns:a period representing the number of seconds for this number of weeks
/**
     * Converts this period in weeks to a period in seconds assuming a
     * 7 day week, 24 hour day, 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 weeks are
     * 7 days long, all days are 24 hours long, all hours are 60 minutes long
     * and all minutes are 60 seconds long.
     * This is not true when daylight savings 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 seconds for this number of weeks
     * @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_WEEK));
    }

    //-----------------------------------------------------------------------
    
Converts this period in weeks to a duration in milliweeks assuming a
7 day week, 24 hour day, 60 minute hour and 60 second minute.


This method allows you to convert from a period to a duration.
However to achieve this it makes the assumption that all weeks are
7 days long, all days are 24 hours long, all hours are 60 minutes long
and all minutes are 60 seconds 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.

Returns:a duration equivalent to this number of weeks
/**
     * Converts this period in weeks to a duration in milliweeks assuming a
     * 7 day week, 24 hour day, 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 weeks are
     * 7 days long, all days are 24 hours long, all hours are 60 minutes long
     * and all minutes are 60 seconds 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 duration equivalent to this number of weeks
     */
    public Duration toStandardDuration() {
        long weeks = getValue();  // assign to a long
        return new Duration(weeks * DateTimeConstants.MILLIS_PER_WEEK);
    }

    //-----------------------------------------------------------------------
    
Gets the number of weeks that this period represents.

Returns:the number of weeks in the period
/**
     * Gets the number of weeks that this period represents.
     *
     * @return the number of weeks in the period
     */
    public int getWeeks() {
        return getValue();
    }

    //-----------------------------------------------------------------------
    
Returns a new instance with the specified number of weeks added.


This instance is immutable and unaffected by this method call.

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

    
Returns a new instance with the specified number of weeks added.


This instance is immutable and unaffected by this method call.

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

    //-----------------------------------------------------------------------
    
Returns a new instance with the specified number of weeks taken away.


This instance is immutable and unaffected by this method call.

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

    
Returns a new instance with the specified number of weeks taken away.


This instance is immutable and unaffected by this method call.

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

    //-----------------------------------------------------------------------
    
Returns a new instance with the weeks multiplied by the specified scalar.


This instance is immutable and unaffected by this method call.

Params:
  • scalar –  the amount to multiply by, may be negative
Throws:
Returns:the new period multiplied by the specified scalar
/**
     * Returns a new instance with the weeks 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 Weeks multipliedBy(int scalar) {
        return Weeks.weeks(FieldUtils.safeMultiply(getValue(), scalar));
    }

    
Returns a new instance with the weeks divided by the specified divisor.
The calculation uses integer division, thus 3 divided by 2 is 1.


This instance is immutable and unaffected by this method call.

Params:
  • divisor –  the amount to divide by, may be negative
Throws:
Returns:the new period divided by the specified divisor
/**
     * Returns a new instance with the weeks 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 Weeks dividedBy(int divisor) {
        if (divisor == 1) {
            return this;
        }
        return Weeks.weeks(getValue() / divisor);
    }

    //-----------------------------------------------------------------------
    
Returns a new instance with the weeks value negated.

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

    //-----------------------------------------------------------------------
    
Is this weeks instance greater than the specified number of weeks.

Params:
  • other –  the other period, null means zero
Returns:true if this weeks instance is greater than the specified one
/**
     * Is this weeks instance greater than the specified number of weeks.
     *
     * @param other  the other period, null means zero
     * @return true if this weeks instance is greater than the specified one
     */
    public boolean isGreaterThan(Weeks other) {
        if (other == null) {
            return getValue() > 0;
        }
        return getValue() > other.getValue();
    }

    
Is this weeks instance less than the specified number of weeks.

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

    //-----------------------------------------------------------------------
    
Gets this instance as a String in the ISO8601 duration format.


For example, "P4W" represents 4 weeks.

Returns:the value as an ISO8601 string
/**
     * Gets this instance as a String in the ISO8601 duration format.
     * <p>
     * For example, "P4W" represents 4 weeks.
     *
     * @return the value as an ISO8601 string
     */
    @ToString
    public String toString() {
        return "P" + String.valueOf(getValue()) + "W";
    }

}