Duration as an int or 0 if not present.
*
* <p>getYears() is a convenience method for
* {@link #getField(DatatypeConstants.Field field) getField(DatatypeConstants.YEARS)}.</p>
*
* <p>As the return value is an int, an incorrect value will be returned for Durations
* with years that go beyond the range of an <code>int.
* Use {@link #getField(DatatypeConstants.Field field) getField(DatatypeConstants.YEARS)} to avoid possible loss of precision.</p>
*
* @return If the years field is present, return its value as an <code>int, else return 0.
*/
public int getYears() {
return getField(DatatypeConstants.YEARS).intValue();
}
/**
* Obtains the value of the MONTHS field as an integer value,
* or 0 if not present.
*
* This method works just like {@link #getYears()} except
* that this method works on the MONTHS field.
*
* @return Months of this <code>Duration.
*/
public int getMonths() {
return getField(DatatypeConstants.MONTHS).intValue();
}
/**
* Obtains the value of the DAYS field as an integer value,
* or 0 if not present.
*
* This method works just like {@link #getYears()} except
* that this method works on the DAYS field.
*
* @return Days of this <code>Duration.
*/
public int getDays() {
return getField(DatatypeConstants.DAYS).intValue();
}
/**
* Obtains the value of the HOURS field as an integer value,
* or 0 if not present.
*
* This method works just like {@link #getYears()} except
* that this method works on the HOURS field.
*
* @return Hours of this <code>Duration.
*
*/
public int getHours() {
return getField(DatatypeConstants.HOURS).intValue();
}
/**
* Obtains the value of the MINUTES field as an integer value,
* or 0 if not present.
*
* This method works just like {@link #getYears()} except
* that this method works on the MINUTES field.
*
* @return Minutes of this <code>Duration.
*
*/
public int getMinutes() {
return getField(DatatypeConstants.MINUTES).intValue();
}
/**
* Obtains the value of the SECONDS field as an integer value,
* or 0 if not present.
*
* This method works just like {@link #getYears()} except
* that this method works on the SECONDS field.
*
* @return seconds in the integer value. The fraction of seconds
* will be discarded (for example, if the actual value is 2.5,
* this method returns 2)
*/
public int getSeconds() {
return getField(DatatypeConstants.SECONDS).intValue();
}
/**
* <p>Returns the length of the duration in milli-seconds.
*
* <p>If the seconds field carries more digits than milli-second order,
* those will be simply discarded (or in other words, rounded to zero.)
* For example, for any Calendar value <code>x,
* <pre>
* <code>new Duration("PT10.00099S").getTimeInMills(x) == 10000.
* <code>new Duration("-PT10.00099S").getTimeInMills(x) == -10000.
* </pre>
*
* <p>
* Note that this method uses the {@link #addTo(Calendar)} method,
* which may work incorrectly with <code>Duration objects with
* very large values in its fields. See the {@link #addTo(Calendar)}
* method for details.
*
* @param startInstant
* The length of a month/year varies. The <code>startInstant is
* used to disambiguate this variance. Specifically, this method
* returns the difference between <code>startInstant and
* <code>startInstant+duration
*
* @return milliseconds between <code>startInstant and
* <code>startInstant plus this Duration
*
* @throws NullPointerException if <code>startInstant parameter
* is null.
*
*/
public long getTimeInMillis(final Calendar startInstant) {
Calendar cal = (Calendar) startInstant.clone();
addTo(cal);
return getCalendarTimeInMillis(cal)
- getCalendarTimeInMillis(startInstant);
}
/**
* <p>Returns the length of the duration in milli-seconds.
*
* <p>If the seconds field carries more digits than milli-second order,
* those will be simply discarded (or in other words, rounded to zero.)
* For example, for any <code>Date value x,
* <pre>
* <code>new Duration("PT10.00099S").getTimeInMills(x) == 10000.
* <code>new Duration("-PT10.00099S").getTimeInMills(x) == -10000.
* </pre>
*
* <p>
* Note that this method uses the {@link #addTo(Date)} method,
* which may work incorrectly with <code>Duration objects with
* very large values in its fields. See the {@link #addTo(Date)}
* method for details.
*
* @param startInstant
* The length of a month/year varies. The <code>startInstant is
* used to disambiguate this variance. Specifically, this method
* returns the difference between <code>startInstant and
* <code>startInstant+duration.
*
* @throws NullPointerException
* If the startInstant parameter is null.
*
* @return milliseconds between <code>startInstant and
* <code>startInstant plus this Duration
*
* @see #getTimeInMillis(Calendar)
*/
public long getTimeInMillis(final Date startInstant) {
Calendar cal = new GregorianCalendar();
cal.setTime(startInstant);
this.addTo(cal);
return getCalendarTimeInMillis(cal) - startInstant.getTime();
}
/**
* Gets the value of a field.
*
* Fields of a duration object may contain arbitrary large value.
* Therefore this method is designed to return a {@link Number} object.
*
* In case of YEARS, MONTHS, DAYS, HOURS, and MINUTES, the returned
* number will be a non-negative integer. In case of seconds,
* the returned number may be a non-negative decimal value.
*
* @param field
* one of the six Field constants (YEARS,MONTHS,DAYS,HOURS,
* MINUTES, or SECONDS.)
* @return
* If the specified field is present, this method returns
* a non-null non-negative {@link Number} object that
* represents its value. If it is not present, return null.
* For YEARS, MONTHS, DAYS, HOURS, and MINUTES, this method
* returns a {@link java.math.BigInteger} object. For SECONDS, this
* method returns a {@link java.math.BigDecimal}.
*
* @throws NullPointerException If the <code>field is null.
*/
public abstract Number getField(final DatatypeConstants.Field field);
/**
* Checks if a field is set.
*
* A field of a duration object may or may not be present.
* This method can be used to test if a field is present.
*
* @param field
* one of the six Field constants (YEARS,MONTHS,DAYS,HOURS,
* MINUTES, or SECONDS.)
* @return
* true if the field is present. false if not.
*
* @throws NullPointerException
* If the field parameter is null.
*/
public abstract boolean isSet(final DatatypeConstants.Field field);
/**
* <p>Computes a new duration whose value is this+rhs.
*
* <p>For example,
* <pre>
* "1 day" + "-3 days" = "-2 days"
* "1 year" + "1 day" = "1 year and 1 day"
* "-(1 hour,50 minutes)" + "-20 minutes" = "-(1 hours,70 minutes)"
* "15 hours" + "-3 days" = "-(2 days,9 hours)"
* "1 year" + "-1 day" = IllegalStateException
* </pre>
*
* <p>Since there's no way to meaningfully subtract 1 day from 1 month,
* there are cases where the operation fails in
* {@link IllegalStateException}.</p>
*
* <p>
* Formally, the computation is defined as follows.</p>
* <p>
* Firstly, we can assume that two <code>Durations to be added
* are both positive without losing generality (i.e.,
* <code>(-X)+Y=Y-X, X+(-Y)=X-Y,
* <code>(-X)+(-Y)=-(X+Y))
*
* <p>
* Addition of two positive <code>Durations are simply defined as
* field by field addition where missing fields are treated as 0.
* <p>
* A field of the resulting <code>Duration will be unset if and
* only if respective fields of two input <code>Durations are unset.
* <p>
* Note that <code>lhs.add(rhs) will be always successful if
* <code>lhs.signum()*rhs.signum()!=-1 or both of them are
* normalized.</p>
*
* @param rhs <code>Duration to add to this Duration
*
* @return
* non-null valid Duration object.
*
* @throws NullPointerException
* If the rhs parameter is null.
* @throws IllegalStateException
* If two durations cannot be meaningfully added. For
* example, adding negative one day to one month causes
* this exception.
*
*
* @see #subtract(Duration)
*/
public abstract Duration add(final Duration rhs);
/**
* Adds this duration to a {@link Calendar} object.
*
* <p>
* Calls {@link java.util.Calendar#add(int,int)} in the
* order of YEARS, MONTHS, DAYS, HOURS, MINUTES, SECONDS, and MILLISECONDS
* if those fields are present. Because the {@link Calendar} class
* uses int to hold values, there are cases where this method
* won't work correctly (for example if values of fields
* exceed the range of int.)
* </p>
*
* <p>
* Also, since this duration class is a Gregorian duration, this
* method will not work correctly if the given {@link Calendar}
* object is based on some other calendar systems.
* </p>
*
* <p>
* Any fractional parts of this <code>Duration object
* beyond milliseconds will be simply ignored. For example, if
* this duration is "P1.23456S", then 1 is added to SECONDS,
* 234 is added to MILLISECONDS, and the rest will be unused.
* </p>
*
* <p>
* Note that because {@link Calendar#add(int, int)} is using
* <code>int, Duration with values beyond the
* range of <code>int in its fields
* will cause overflow/underflow to the given {@link Calendar}.
* {@link XMLGregorianCalendar#add(Duration)} provides the same
* basic operation as this method while avoiding
* the overflow/underflow issues.
*
* @param calendar
* A calendar object whose value will be modified.
* @throws NullPointerException
* if the calendar parameter is null.
*/
public abstract void addTo(Calendar calendar);
/**
* Adds this duration to a {@link Date} object.
*
* <p>
* The given date is first converted into
* a {@link java.util.GregorianCalendar}, then the duration
* is added exactly like the {@link #addTo(Calendar)} method.
*
* <p>
* The updated time instant is then converted back into a
* {@link Date} object and used to update the given {@link Date} object.
*
* <p>
* This somewhat redundant computation is necessary to unambiguously
* determine the duration of months and years.
*
* @param date
* A date object whose value will be modified.
* @throws NullPointerException
* if the date parameter is null.
*/
public void addTo(Date date) {
// check data parameter
if (date == null) {
throw new NullPointerException(
"Cannot call "
+ this.getClass().getName()
+ "#addTo(Date date) with date == null."
);
}
Calendar cal = new GregorianCalendar();
cal.setTime(date);
this.addTo(cal);
date.setTime(getCalendarTimeInMillis(cal));
}
/**
* <p>Computes a new duration whose value is this-rhs.
*
* <p>For example:
* <pre>
* "1 day" - "-3 days" = "4 days"
* "1 year" - "1 day" = IllegalStateException
* "-(1 hour,50 minutes)" - "-20 minutes" = "-(1hours,30 minutes)"
* "15 hours" - "-3 days" = "3 days and 15 hours"
* "1 year" - "-1 day" = "1 year and 1 day"
* </pre>
*
* <p>Since there's no way to meaningfully subtract 1 day from 1 month,
* there are cases where the operation fails in {@link IllegalStateException}.</p>
*
* <p>Formally the computation is defined as follows.
* First, we can assume that two <code>Durations are both positive
* without losing generality. (i.e.,
* <code>(-X)-Y=-(X+Y), X-(-Y)=X+Y,
* <code>(-X)-(-Y)=-(X-Y))
*
* <p>Then two durations are subtracted field by field.
* If the sign of any non-zero field <code>F is different from
* the sign of the most significant field,
* 1 (if <code>F is negative) or -1 (otherwise)
* will be borrowed from the next bigger unit of <code>F.
*
* <p>This process is repeated until all the non-zero fields have
* the same sign.</p>
*
* <p>If a borrow occurs in the days field (in other words, if
* the computation needs to borrow 1 or -1 month to compensate
* days), then the computation fails by throwing an
* {@link IllegalStateException}.</p>
*
* @param rhs <code>Duration to subtract from this Duration.
*
* @return New <code>Duration created from subtracting rhs from this Duration.
*
* @throws IllegalStateException
* If two durations cannot be meaningfully subtracted. For
* example, subtracting one day from one month causes
* this exception.
*
* @throws NullPointerException
* If the rhs parameter is null.
*
* @see #add(Duration)
*/
public Duration subtract(final Duration rhs) {
return add(rhs.negate());
}
/**
* <p>Computes a new duration whose value is factor times
* longer than the value of this duration.</p>
*
* <p>This method is provided for the convenience.
* It is functionally equivalent to the following code:</p>
* <pre>
* multiply(new BigDecimal(String.valueOf(factor)))
* </pre>
*
* @param factor Factor times longer of new <code>Duration to create.
*
* @return New <code>Duration that is factortimes longer than this Duration.
*
* @see #multiply(BigDecimal)
*/
public Duration multiply(int factor) {
return multiply(new BigDecimal(String.valueOf(factor)));
}
/**
* Computes a new duration whose value is <code>factor times
* longer than the value of this duration.
*
* <p>
* For example,
* <pre>
* "P1M" (1 month) * "12" = "P12M" (12 months)
* "PT1M" (1 min) * "0.3" = "PT18S" (18 seconds)
* "P1M" (1 month) * "1.5" = IllegalStateException
* </pre>
*
* <p>
* Since the <code>Duration class is immutable, this method
* doesn't change the value of this object. It simply computes
* a new Duration object and returns it.
*
* <p>
* The operation will be performed field by field with the precision
* of {@link BigDecimal}. Since all the fields except seconds are
* restricted to hold integers,
* any fraction produced by the computation will be
* carried down toward the next lower unit. For example,
* if you multiply "P1D" (1 day) with "0.5", then it will be 0.5 day,
* which will be carried down to "PT12H" (12 hours).
* When fractions of month cannot be meaningfully carried down
* to days, or year to months, this will cause an
* {@link IllegalStateException} to be thrown.
* For example if you multiple one month by 0.5.</p>
*
* <p>
* To avoid {@link IllegalStateException}, use
* the {@link #normalizeWith(Calendar)} method to remove the years
* and months fields.
*
* @param factor to multiply by
*
* @return
* returns a non-null valid <code>Duration object
*
* @throws IllegalStateException if operation produces fraction in
* the months field.
*
* @throws NullPointerException if the <code>factor parameter is
* <code>null.
*
*/
public abstract Duration multiply(final BigDecimal factor);
/**
* Returns a new <code>Duration object whose
* value is <code>-this.
*
* <p>
* Since the <code>Duration class is immutable, this method
* doesn't change the value of this object. It simply computes
* a new Duration object and returns it.
*
* @return
* always return a non-null valid <code>Duration object.
*/
public abstract Duration negate();
/**
* <p>Converts the years and months fields into the days field
* by using a specific time instant as the reference point.</p>
*
* <p>For example, duration of one month normalizes to 31 days
* given the start time instance "July 8th 2003, 17:40:32".</p>
*
* <p>Formally, the computation is done as follows:
* <ol>
* <li>the given Calendar object is cloned
* <li>the years, months and days fields will be added to the {@link Calendar} object
* by using the {@link Calendar#add(int,int)} method</li>
* <li>the difference between the two Calendars in computed in milliseconds and converted to days,
* if a remainder occurs due to Daylight Savings Time, it is discarded</li>
* <li>the computed days, along with the hours, minutes and seconds
* fields of this duration object is used to construct a new
* Duration object.</li>
* </ol>
*
* <p>Note that since the Calendar class uses int to
* hold the value of year and month, this method may produce
* an unexpected result if this duration object holds
* a very large value in the years or months fields.</p>
*
* @param startTimeInstant <code>Calendar reference point.
*
* @return <code>Duration of years and months of this Duration as days.
*
* @throws NullPointerException If the startTimeInstant parameter is null.
*/
public abstract Duration normalizeWith(final Calendar startTimeInstant);
/**
* <p>Partial order relation comparison with this Duration instance.
*
* <p>Comparison result must be in accordance with
* <a href="http://www.w3.org/TR/xmlschema-2/#duration-order">W3C XML Schema 1.0 Part 2, Section 3.2.7.6.2,
* <i>Order relation on duration.
*
* <p>Return:
* <ul>
* <li>{@link DatatypeConstants#LESSER} if this Duration is shorter than duration parameter
* <li>{@link DatatypeConstants#EQUAL} if this Duration is equal to duration parameter
* <li>{@link DatatypeConstants#GREATER} if this Duration is longer than duration parameter
* <li>{@link DatatypeConstants#INDETERMINATE} if a conclusive partial order relation cannot be determined
* </ul>
*
* @param duration to compare
*
* @return the relationship between <code>thisDurationand duration parameter as
* {@link DatatypeConstants#LESSER}, {@link DatatypeConstants#EQUAL}, {@link DatatypeConstants#GREATER}
* or {@link DatatypeConstants#INDETERMINATE}.
*
* @throws UnsupportedOperationException If the underlying implementation
* cannot reasonably process the request, e.g. W3C XML Schema allows for
* arbitrarily large/small/precise values, the request may be beyond the
* implementations capability.
* @throws NullPointerException if <code>duration is null.
*
* @see #isShorterThan(Duration)
* @see #isLongerThan(Duration)
*/
public abstract int compare(final Duration duration);
/**
* <p>Checks if this duration object is strictly longer than
* another <code>Duration object.
*
* <p>Duration X is "longer" than Y if and only if X>Y
* as defined in the section 3.2.6.2 of the XML Schema 1.0
* specification.</p>
*
* <p>For example, "P1D" (one day) > "PT12H" (12 hours) and
* "P2Y" (two years) > "P23M" (23 months).</p>
*
* @param duration <code>Duration to test this Duration against.
*
* @throws UnsupportedOperationException If the underlying implementation
* cannot reasonably process the request, e.g. W3C XML Schema allows for
* arbitrarily large/small/precise values, the request may be beyond the
* implementations capability.
* @throws NullPointerException If <code>duration is null.
*
* @return
* true if the duration represented by this object
* is longer than the given duration. false otherwise.
*
* @see #isShorterThan(Duration)
* @see #compare(Duration duration)
*/
public boolean isLongerThan(final Duration duration) {
return compare(duration) == DatatypeConstants.GREATER;
}
/**
* <p>Checks if this duration object is strictly shorter than
* another <code>Duration object.
*
* @param duration <code>Duration to test this Duration against.
*
* @return <code>true if duration parameter is shorter than this Duration,
* else <code>false.
*
* @throws UnsupportedOperationException If the underlying implementation
* cannot reasonably process the request, e.g. W3C XML Schema allows for
* arbitrarily large/small/precise values, the request may be beyond the
* implementations capability.
* @throws NullPointerException if <code>duration is null.
*
* @see #isLongerThan(Duration duration)
* @see #compare(Duration duration)
*/
public boolean isShorterThan(final Duration duration) {
return compare(duration) == DatatypeConstants.LESSER;
}
/**
* <p>Checks if this duration object has the same duration
* as another <code>Duration object.
*
* <p>For example, "P1D" (1 day) is equal to "PT24H" (24 hours).
*
* <p>Duration X is equal to Y if and only if time instant
* t+X and t+Y are the same for all the test time instants
* specified in the section 3.2.6.2 of the XML Schema 1.0
* specification.</p>
*
* <p>Note that there are cases where two Durations are
* "incomparable" to each other, like one month and 30 days.
* For example,</p>
* <pre>
* !new Duration("P1M").isShorterThan(new Duration("P30D"))
* !new Duration("P1M").isLongerThan(new Duration("P30D"))
* !new Duration("P1M").equals(new Duration("P30D"))
* </pre>
*
* @param duration
* The object to compare this <code>Duration against.
*
* @return
* <code>true if this duration is the same length as
* <code>duration.
* <code>false if duration is null,
* is not a
* <code>Duration object,
* or its length is different from this duration.
*
* @throws UnsupportedOperationException If the underlying implementation
* cannot reasonably process the request, e.g. W3C XML Schema allows for
* arbitrarily large/small/precise values, the request may be beyond the
* implementations capability.
*
* @see #compare(Duration duration)
*/
public boolean equals(final Object duration) {
if (duration == null || !(duration instanceof Duration)) {
return false;
}
return compare((Duration) duration) == DatatypeConstants.EQUAL;
}
/**
* Returns a hash code consistent with the definition of the equals method.
*
* @see Object#hashCode()
*/
public abstract int hashCode();
/**
* <p>Returns a String representation of this DurationObject.
*
* <p>The result is formatted according to the XML Schema 1.0 spec and can be always parsed back later into the
* equivalent <code>DurationObject by {@link DatatypeFactory#newDuration(String lexicalRepresentation)}.
*
* <p>Formally, the following holds for any Duration
* <code>Object x:
* <pre>
* new Duration(x.toString()).equals(x)
* </pre>
*
* @return A non-<code>null valid String representation of this Duration.
*/
public String toString() {
StringBuffer buf = new StringBuffer();
if (getSign() < 0) {
buf.append('-');
}
buf.append('P');
BigInteger years = (BigInteger) getField(DatatypeConstants.YEARS);
if (years != null) {
buf.append(years + "Y");
}
BigInteger months = (BigInteger) getField(DatatypeConstants.MONTHS);
if (months != null) {
buf.append(months + "M");
}
BigInteger days = (BigInteger) getField(DatatypeConstants.DAYS);
if (days != null) {
buf.append(days + "D");
}
BigInteger hours = (BigInteger) getField(DatatypeConstants.HOURS);
BigInteger minutes = (BigInteger) getField(DatatypeConstants.MINUTES);
BigDecimal seconds = (BigDecimal) getField(DatatypeConstants.SECONDS);
if (hours != null || minutes != null || seconds != null) {
buf.append('T');
if (hours != null) {
buf.append(hours + "H");
}
if (minutes != null) {
buf.append(minutes + "M");
}
if (seconds != null) {
buf.append(toString(seconds) + "S");
}
}
return buf.toString();
}
/**
* <p>Turns {@link BigDecimal} to a string representation.
*
* <p>Due to a behavior change in the {@link BigDecimal#toString()}
* method in JDK1.5, this had to be implemented here.</p>
*
* @param bd <code>BigDecimal to format as a String
*
* @return <code>String representation of BigDecimal
*/
private String toString(BigDecimal bd) {
String intString = bd.unscaledValue().toString();
int scale = bd.scale();
if (scale == 0) {
return intString;
}
/* Insert decimal point */
StringBuffer buf;
int insertionPoint = intString.length() - scale;
if (insertionPoint == 0) { /* Point goes right before intVal */
return "0." + intString;
} else if (insertionPoint > 0) { /* Point goes inside intVal */
buf = new StringBuffer(intString);
buf.insert(insertionPoint, '.');
} else { /* We must insert zeros between point and intVal */
buf = new StringBuffer(3 - insertionPoint + intString.length());
buf.append("0.");
for (int i = 0; i < -insertionPoint; i++) {
buf.append('0');
}
buf.append(intString);
}
return buf.toString();
}
/**
* <p>Calls the {@link Calendar#getTimeInMillis} method.
* Prior to JDK1.4, this method was protected and therefore
* cannot be invoked directly.</p>
*
* <p>TODO: In future, this should be replaced by cal.getTimeInMillis().
*
* @param cal <code>Calendar to get time in milliseconds.
*
* @return Milliseconds of <code>cal.
*/
private static long getCalendarTimeInMillis(final Calendar cal) {
return cal.getTime().getTime();
}
}
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Java example source code file (Duration.java)
The Duration.java Java example source code/*
* Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.xml.datatype;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import javax.xml.namespace.QName;
/**
* <p>Immutable representation of a time span as defined in
* the W3C XML Schema 1.0 specification.</p>
*
* <p>A Duration object represents a period of Gregorian time,
* which consists of six fields (years, months, days, hours,
* minutes, and seconds) plus a sign (+/-) field.</p>
*
* <p>The first five fields have non-negative (>=0) integers or null
* (which represents that the field is not set),
* and the seconds field has a non-negative decimal or null.
* A negative sign indicates a negative duration.</p>
*
* <p>This class provides a number of methods that make it easy
* to use for the duration datatype of XML Schema 1.0 with
* the errata.</p>
*
* <h2>Order relationship
* <p>Duration objects only have partial order, where two values A and B
* maybe either:</p>
* <ol>
* <li>A<B (A is shorter than B)
* <li>A>B (A is longer than B)
* <li>A==B (A and B are of the same duration)
* <li>A<>B (Comparison between A and B is indeterminate)
* </ol>
*
* <p>For example, 30 days cannot be meaningfully compared to one month.
* The {@link #compare(Duration duration)} method implements this
* relationship.</p>
*
* <p>See the {@link #isLongerThan(Duration)} method for details about
* the order relationship among <code>Duration objects.
*
* <h2>Operations over Duration
* <p>This class provides a set of basic arithmetic operations, such
* as addition, subtraction and multiplication.
* Because durations don't have total order, an operation could
* fail for some combinations of operations. For example, you cannot
* subtract 15 days from 1 month. See the javadoc of those methods
* for detailed conditions where this could happen.</p>
*
* <p>Also, division of a duration by a number is not provided because
* the <code>Duration class can only deal with finite precision
* decimal numbers. For example, one cannot represent 1 sec divided by 3.</p>
*
* <p>However, you could substitute a division by 3 with multiplying
* by numbers such as 0.3 or 0.333.</p>
*
* <h2>Range of allowed values
* <p>
* Because some operations of <code>Duration rely on {@link Calendar}
* even though {@link Duration} can hold very large or very small values,
* some of the methods may not work correctly on such <code>Durations.
* The impacted methods document their dependency on {@link Calendar}.
*
* @author <a href="mailto:Joseph.Fialli@Sun.COM">Joseph Fialli
* @author <a href="mailto:Kohsuke.Kawaguchi@Sun.com">Kohsuke Kawaguchi
* @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor
* @author <a href="mailto:Sunitha.Reddy@Sun.com">Sunitha Reddy
* @see XMLGregorianCalendar#add(Duration)
* @since 1.5
*/
public abstract class Duration {
/**
* <p>Debugging |
