package io.dropwizard.jdbi.args;

import org.skife.jdbi.v2.StatementContext;
import org.skife.jdbi.v2.tweak.ResultColumnMapper;

import javax.annotation.Nullable;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.time.Instant;
import java.time.OffsetDateTime;
import java.time.ZoneId;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Optional;
import java.util.TimeZone;

/**
 * A {@link ResultColumnMapper} to map {@link OffsetDateTime} objects.
 */
public class OffsetDateTimeMapper implements ResultColumnMapper<OffsetDateTime> {

    

Calendar for representing a database time zone.

If a field is not represented in a database as TIMESTAMP WITH TIME ZONE, we need to set its time zone explicitly. Otherwise it will not be correctly represented in a time zone different from the time zone of the database.

/** * <p>{@link Calendar} for representing a database time zone.<p> * If a field is not represented in a database as * {@code TIMESTAMP WITH TIME ZONE}, we need to set its time zone * explicitly. Otherwise it will not be correctly represented in * a time zone different from the time zone of the database. */
private Optional<Calendar> calendar; public OffsetDateTimeMapper() { calendar = Optional.empty(); } public OffsetDateTimeMapper(Optional<TimeZone> timeZone) { calendar = timeZone.map(GregorianCalendar::new); }
Make a clone of a calendar.

Despite the fact that Calendar is used only for representing a time zone, some JDBC drivers actually use it for time calculations,

Also Calendar is not immutable, which makes it thread-unsafe. Therefore we need to make a copy to avoid state mutation problems.

Returns:a clone of calendar, representing a database time zone
/** * Make a clone of a calendar. * <p>Despite the fact that {@link Calendar} is used only for * representing a time zone, some JDBC drivers actually use it * for time calculations,</p> * <p>Also {@link Calendar} is not immutable, which makes it * thread-unsafe. Therefore we need to make a copy to avoid * state mutation problems.</p> * * @return a clone of calendar, representing a database time zone */
private Calendar cloneCalendar() { return (Calendar) calendar.get().clone(); } @Override @Nullable public OffsetDateTime mapColumn(ResultSet r, int columnNumber, StatementContext ctx) throws SQLException { final Timestamp timestamp = calendar.isPresent() ? r.getTimestamp(columnNumber, cloneCalendar()) : r.getTimestamp(columnNumber); return convertToOffsetDateTime(timestamp); } @Override @Nullable public OffsetDateTime mapColumn(ResultSet r, String columnLabel, StatementContext ctx) throws SQLException { final Timestamp timestamp = calendar.isPresent() ? r.getTimestamp(columnLabel, cloneCalendar()) : r.getTimestamp(columnLabel); return convertToOffsetDateTime(timestamp); } @Nullable private OffsetDateTime convertToOffsetDateTime(Timestamp timestamp) { if (timestamp == null) { return null; } final Optional<ZoneId> zoneId = calendar.flatMap(c -> Optional.of(c.getTimeZone().toZoneId())); return OffsetDateTime.ofInstant( Instant.ofEpochSecond(timestamp.getTime() / 1000, timestamp.getNanos()), zoneId.orElse(ZoneId.systemDefault())); } }