Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/5240#discussion_r164168602
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/descriptors/Rowtime.scala
---
@@ -0,0 +1,131 @@
+/*
+ * 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.flink.table.descriptors
+
+import org.apache.flink.table.api.Types
+import
org.apache.flink.table.descriptors.NormalizedProperties.{normalizeTimestampExtractor,
normalizeWatermarkStrategy}
+import org.apache.flink.table.sources.tsextractors.{ExistingField,
StreamRecordTimestamp, TimestampExtractor}
+import org.apache.flink.table.sources.wmstrategies.{AscendingTimestamps,
BoundedOutOfOrderTimestamps, PreserveWatermarks, WatermarkStrategy}
+
+import scala.collection.mutable
+
+/**
+ * Rowtime descriptor for describing an event time attribute in the
schema.
+ */
+class Rowtime extends Descriptor {
+
+ private var timestampExtractor: Option[TimestampExtractor] = None
+ private var watermarkStrategy: Option[WatermarkStrategy] = None
+
+ /**
+ * Sets a built-in timestamp extractor that converts an existing
[[Long]] or
+ * [[Types.SQL_TIMESTAMP]] field into the rowtime attribute.
+ *
+ * @param fieldName The field to convert into a rowtime attribute.
+ */
+ def timestampFromField(fieldName: String): Rowtime = {
+ timestampExtractor = Some(new ExistingField(fieldName))
+ this
+ }
+
+ /**
+ * Sets a built-in timestamp extractor that converts the assigned
timestamp from
+ * a DataStream API record into the rowtime attribute.
+ *
+ * Note: This extractor only works in streaming environments.
+ */
+ def timestampFromDataStream(): Rowtime = {
+ timestampExtractor = Some(new StreamRecordTimestamp)
+ this
+ }
+
+ /**
+ * Sets a custom timestamp extractor to be used for the rowtime
attribute.
+ *
+ * @param extractor The [[TimestampExtractor]] to extract the rowtime
attribute
+ * from the physical type.
+ */
+ def timestampFromExtractor(extractor: TimestampExtractor): Rowtime = {
--- End diff --
`timestampsFromExtractor()`
---
