500          *
 501          * <p>Value constraints for this value are summarized in
 502          * <a href="#datetimefield-year">year field of date/time field mapping table</a>.
 503          *
 504          * @return sum of {@code eon} and {@code BigInteger.valueOf(year)}
 505          * when both fields are defined. When only {@code year} is defined,
 506          * return it. When both {@code eon} and {@code year} are not
 507          * defined, return {@code null}.
 508          *
 509          * @see #getEon()
 510          * @see #getYear()
 511          */
 512         public abstract BigInteger getEonAndYear();
 513 
 514         /**
 515          * Return number of month or {@link DatatypeConstants#FIELD_UNDEFINED}.
 516          *
 517          * <p>Value constraints for this value are summarized in
 518          * <a href="#datetimefield-month">month field of date/time field mapping table</a>.
 519          *
 520          * @return year  of this {@code XMLGregorianCalendar}.
 521          *
 522          */
 523         public abstract int getMonth();
 524 
 525         /**
 526          * Return day in month or {@link DatatypeConstants#FIELD_UNDEFINED}.
 527          *
 528          * <p>Value constraints for this value are summarized in
 529          * <a href="#datetimefield-day">day field of date/time field mapping table</a>.
 530          *
 531          * @see #setDay(int)
 532          */
 533         public abstract int getDay();
 534 
 535         /**
 536          * Return timezone offset in minutes or
 537          * {@link DatatypeConstants#FIELD_UNDEFINED} if this optional field is not defined.
 538          *
 539          * <p>Value constraints for this value are summarized in
 540          * <a href="#datetimefield-timezone">timezone field of date/time field mapping table</a>.

 500          *
 501          * <p>Value constraints for this value are summarized in
 502          * <a href="#datetimefield-year">year field of date/time field mapping table</a>.
 503          *
 504          * @return sum of {@code eon} and {@code BigInteger.valueOf(year)}
 505          * when both fields are defined. When only {@code year} is defined,
 506          * return it. When both {@code eon} and {@code year} are not
 507          * defined, return {@code null}.
 508          *
 509          * @see #getEon()
 510          * @see #getYear()
 511          */
 512         public abstract BigInteger getEonAndYear();
 513 
 514         /**
 515          * Return number of month or {@link DatatypeConstants#FIELD_UNDEFINED}.
 516          *
 517          * <p>Value constraints for this value are summarized in
 518          * <a href="#datetimefield-month">month field of date/time field mapping table</a>.
 519          *
 520          * @return month of this {@code XMLGregorianCalendar}.
 521          *
 522          */
 523         public abstract int getMonth();
 524 
 525         /**
 526          * Return day in month or {@link DatatypeConstants#FIELD_UNDEFINED}.
 527          *
 528          * <p>Value constraints for this value are summarized in
 529          * <a href="#datetimefield-day">day field of date/time field mapping table</a>.
 530          *
 531          * @see #setDay(int)
 532          */
 533         public abstract int getDay();
 534 
 535         /**
 536          * Return timezone offset in minutes or
 537          * {@link DatatypeConstants#FIELD_UNDEFINED} if this optional field is not defined.
 538          *
 539          * <p>Value constraints for this value are summarized in
 540          * <a href="#datetimefield-timezone">timezone field of date/time field mapping table</a>.