/**
* Queries this offset using the specified query.
*
* <p>This queries this offset using the specified query strategy object. The {@code
* TemporalQuery} object defines the logic to be used to obtain the result. Read the documentation
* of the query to understand what the result of this method will be.
*
* <p>The result of this method is obtained by invoking the {@link
* TemporalQuery#queryFrom(TemporalAccessor)} method on the specified query passing {@code this}
* as the argument.
*
* @param <R> the type of the result
* @param query the query to invoke, not null
* @return the query result, null may be returned (defined by the query)
* @throws DateTimeException if unable to query (defined by the query)
* @throws ArithmeticException if numeric overflow occurs (defined by the query)
*/
@SuppressWarnings("unchecked")
@Override
public <R> R query(TemporalQuery<R> query) {
if (query == TemporalQueries.offset() || query == TemporalQueries.zone()) {
return (R) this;
}
return TemporalAccessor.super.query(query);
}
/**
* Obtains an instance of {@code ZoneOffset} from a temporal object.
*
* <p>This obtains an offset based on the specified temporal. A {@code TemporalAccessor}
* represents an arbitrary set of date and time information, which this factory converts to an
* instance of {@code ZoneOffset}.
*
* <p>A {@code TemporalAccessor} represents some form of date and time information. This factory
* converts the arbitrary temporal object to an instance of {@code ZoneOffset}.
*
* <p>The conversion uses the {@link TemporalQueries#offset()} query, which relies on extracting
* the {@link ChronoField#OFFSET_SECONDS OFFSET_SECONDS} field.
*
* <p>This method matches the signature of the functional interface {@link TemporalQuery} allowing
* it to be used in queries via method reference, {@code ZoneOffset::from}.
*
* @param temporal the temporal object to convert, not null
* @return the zone-offset, not null
* @throws DateTimeException if unable to convert to an {@code ZoneOffset}
*/
public static ZoneOffset from(TemporalAccessor temporal) {
Objects.requireNonNull(temporal, "temporal");
ZoneOffset offset = temporal.query(TemporalQueries.offset());
if (offset == null) {
throw new DateTimeException(
"Unable to obtain ZoneOffset from TemporalAccessor: "
+ temporal
+ " of type "
+ temporal.getClass().getName());
}
return offset;
}