snuyanzin commented on code in PR #29690:
URL: https://github.com/apache/flink/pull/29690#discussion_r4452565103
##########
flink-table/flink-table-common/src/main/java/org/apache/flink/table/data/utils/VariantCastUtils.java:
##########
@@ -240,42 +256,107 @@ private static String decimalTarget(int precision, int
scale) {
}
/**
- * Reads a timestamp variant as the target {@code TIMESTAMP}. {@link
Variant#getDateTime()}
- * accepts both the microsecond ({@link Variant.Type#TIMESTAMP}) and
nanosecond ({@link
- * Variant.Type#TIMESTAMP_NS}) encodings. Fractional seconds beyond the
target precision are
- * truncated, the same as a regular {@code TIMESTAMP} to {@code
TIMESTAMP(p)} cast.
+ * Reads a timestamp variant as the target {@code TIMESTAMP}. A {@code
TIMESTAMP_LTZ} value is
+ * shifted into the session time zone, the same as a regular {@code
TIMESTAMP_LTZ} to {@code
+ * TIMESTAMP} cast. Fractional seconds beyond the target precision are
truncated.
*/
- public static TimestampData toTimestamp(Variant variant, int precision) {
- final Variant.Type type = variant.getType();
- if (type == Variant.Type.TIMESTAMP || type ==
Variant.Type.TIMESTAMP_NS) {
- return DateTimeUtils.truncate(
- TimestampData.fromLocalDateTime(variant.getDateTime()),
precision);
+ public static TimestampData toTimestamp(Variant variant, int precision,
ZoneId sessionZone) {
+ final LocalDateTime dateTime = toLocalDateTime(variant, sessionZone);
+ if (dateTime == null) {
+ throw unsupportedKind(variant, String.format("TIMESTAMP(%d)",
precision));
}
- throw unsupportedKind(variant, String.format("TIMESTAMP(%d)",
precision));
+ return TimestampData.fromLocalDateTime(
+ dateTime.withNano(truncateNanos(dateTime.getNano(),
precision)));
}
- /** Reads a timestamp with local time zone variant. See {@link
#toTimestamp(Variant, int)}. */
- public static TimestampData toTimestampLtz(Variant variant, int precision)
{
- final Variant.Type type = variant.getType();
- if (type == Variant.Type.TIMESTAMP_LTZ || type ==
Variant.Type.TIMESTAMP_LTZ_NS) {
- return DateTimeUtils.truncate(
- TimestampData.fromInstant(variant.getInstant()),
precision);
+ /**
+ * Reads a timestamp variant as the target {@code TIMESTAMP_LTZ}. A {@code
TIMESTAMP} value is
+ * read as a wall-clock time in the session time zone, the same as a
regular {@code TIMESTAMP}
+ * to {@code TIMESTAMP_LTZ} cast. Fractional seconds beyond the target
precision are truncated.
+ */
+ public static TimestampData toTimestampLtz(Variant variant, int precision,
ZoneId sessionZone) {
+ final Instant instant;
+ switch (variant.getType()) {
+ case TIMESTAMP_LTZ:
+ case TIMESTAMP_LTZ_NS:
+ instant = variant.getInstant();
+ break;
+ case TIMESTAMP:
+ case TIMESTAMP_NS:
+ instant =
variant.getDateTime().atZone(sessionZone).toInstant();
+ break;
+ default:
+ throw unsupportedKind(variant,
String.format("TIMESTAMP_LTZ(%d)", precision));
}
- throw unsupportedKind(variant, String.format("TIMESTAMP_LTZ(%d)",
precision));
+ return TimestampData.fromInstant(
+ Instant.ofEpochSecond(
+ instant.getEpochSecond(),
truncateNanos(instant.getNano(), precision)));
}
/**
- * Reads a time variant as the target {@code TIME}. The runtime TIME
representation is
- * millisecond-of-day, so a variant's microseconds are dropped and any
fractional seconds beyond
- * the target precision are then truncated, the same as a regular {@code
TIME} to {@code
- * TIME(p)} cast.
+ * Reads a date or timestamp variant as the target {@code DATE}, in days
since the epoch. A
+ * timestamp keeps its date, read in the session time zone for a {@code
TIMESTAMP_LTZ}.
*/
- public static int toTime(Variant variant, int precision) {
+ public static int toDate(Variant variant, ZoneId sessionZone) {
+ if (variant.getType() == Variant.Type.DATE) {
+ return (int) variant.getDate().toEpochDay();
+ }
+ final LocalDateTime dateTime = toLocalDateTime(variant, sessionZone);
+ if (dateTime == null) {
+ throw unsupportedKind(variant, "DATE");
+ }
+ return (int) dateTime.toLocalDate().toEpochDay();
+ }
+
+ /**
+ * Reads a time or timestamp variant as the target {@code TIME}. A
timestamp keeps its time of
+ * day, read in the session time zone for a {@code TIMESTAMP_LTZ}. The
runtime TIME
+ * representation is millisecond-of-day, so a variant's microseconds are
dropped and any
+ * fractional seconds beyond the target precision are then truncated, the
same as a regular
+ * {@code TIME} to {@code TIME(p)} cast.
+ */
+ public static int toTime(Variant variant, int precision, ZoneId
sessionZone) {
+ final LocalTime time;
if (variant.getType() == Variant.Type.TIME) {
- return DateTimeUtils.applyTimePrecisionTruncation(
- DateTimeUtils.toInternal(variant.getTime()), precision);
+ time = variant.getTime();
+ } else {
+ final LocalDateTime dateTime = toLocalDateTime(variant,
sessionZone);
+ if (dateTime == null) {
+ throw unsupportedKind(variant, String.format("TIME(%d)",
precision));
+ }
+ time = dateTime.toLocalTime();
}
- throw unsupportedKind(variant, String.format("TIME(%d)", precision));
+ return DateTimeUtils.applyTimePrecisionTruncation(
+ DateTimeUtils.toInternal(time), precision);
+ }
+
+ /**
+ * Reads a timestamp variant as a wall-clock time, shifting a {@code
TIMESTAMP_LTZ} into the
+ * session time zone. Returns {@code null} for any other kind, so that the
caller builds the
+ * error message only when the cast fails.
+ */
+ private static @Nullable LocalDateTime toLocalDateTime(Variant variant,
ZoneId sessionZone) {
+ switch (variant.getType()) {
+ case TIMESTAMP:
+ case TIMESTAMP_NS:
+ return variant.getDateTime();
+ case TIMESTAMP_LTZ:
+ case TIMESTAMP_LTZ_NS:
+ return LocalDateTime.ofInstant(variant.getInstant(),
sessionZone);
+ default:
+ return null;
+ }
+ }
+
+ /**
+ * Zeroes the fractional-second digits beyond the precision. A java.time
nano-of-second is never
+ * negative, so this also truncates toward the past before 1970, unlike
dividing an epoch
+ * millisecond.
+ */
+ private static int truncateNanos(int nanoOfSecond, int precision) {
+ return precision >= TIMESTAMP_NANOS_PRECISION
+ ? nanoOfSecond
+ : nanoOfSecond - nanoOfSecond % NANOS_PER_DIGIT[precision];
Review Comment:
It seems to be different from DateTimeUtils.truncate, is it intended?
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