zhoufek commented on a change in pull request #15733: URL: https://github.com/apache/beam/pull/15733#discussion_r739525908
########## File path: sdks/java/extensions/sbe/src/main/java/org/apache/beam/sdk/extensions/sbe/TimeValues.java ########## @@ -0,0 +1,460 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.beam.sdk.extensions.sbe; + +import static org.apache.beam.sdk.extensions.sbe.Schemas.TZ_TIME_SCHEMA; +import static org.apache.beam.sdk.extensions.sbe.Schemas.TimeFieldNames.TIME_FIELD_NAME; +import static org.apache.beam.sdk.extensions.sbe.Schemas.TimeFieldNames.TIME_ZONE_HOUR_FIELD_NAME; +import static org.apache.beam.sdk.extensions.sbe.Schemas.TimeFieldNames.TIME_ZONE_MINUTE_FIELD_NAME; +import static org.apache.beam.sdk.extensions.sbe.Schemas.TimeFieldNames.UNIT_FIELD_NAME; +import static org.apache.beam.sdk.extensions.sbe.Schemas.UTC_TIME_SCHEMA; +import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument; + +import java.time.Instant; +import java.time.OffsetDateTime; +import java.time.OffsetTime; +import java.time.ZoneOffset; +import java.time.temporal.ChronoUnit; +import java.util.Objects; +import java.util.concurrent.TimeUnit; +import org.apache.beam.sdk.values.Row; +import org.checkerframework.checker.initialization.qual.Initialized; +import org.checkerframework.checker.nullness.qual.NonNull; +import org.checkerframework.checker.nullness.qual.Nullable; + +/** + * Representations of SBE value types. + * + * <p>These are convertible to/from a {@link Row} that is a direct mapping of an SBE composite type. + */ +public final class TimeValues { Review comment: For Row -> T, that'll work. For T -> Row, the difficulty will be recovering the original unit. This isn't an issue if the SBE schema is a variable unit, since we can just pick a unit and set that. However, SBE allows setting a constant unit, like: ``` <composite name="UTCTimestampNanos" description="UTC timestamp with nanosecond precision"> <type name="time" primitiveType="uint64" /> <type name="unit" primitiveType="uint8" presence="constant" valueRef="TimeUnit.nanosecond" /> </composite> ``` ([Source](https://www.fixtrading.org/standards/sbe-online/#date-and-time-encoding)) I'm guessing that there's some potential for detecting this on Row -> SBE type, since the signature will be different: ``` // Variable unit public UTCTimestampEncoder unit(final short value) { buffer.putByte(offset + 8, (byte)value); return this; } // Constant unit public short unit() { return (short)9; } ``` If we assume nanos when doing T -> Row, then going Row -> SBE type, we would either write nanos or reduce precision if constant. So it is doable, but I'm thinking that: 1. It is harder to implement and potentially more error prone. 2. It is more expensive (more analysis of reflection). 3. A sudden unit change might be surprising, even if it is variable. (e.g. "Why did it output nano when I only input seconds and millis?") Overall, I thought it was better to use an intermediate type that bridges the gap between T and Row and which preserves the original value/unit. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
