Github user manuzhang commented on a diff in the pull request:
https://github.com/apache/incubator-gearpump/pull/227#discussion_r147024506
--- Diff:
streaming/src/main/scala/org/apache/gearpump/streaming/task/WatermarkProducer.scala
---
@@ -0,0 +1,21 @@
+/*
+ * 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.gearpump.streaming.task
+
+trait WatermarkProducer
--- End diff --
Please add comments on the purpose of this interface
---
