Github user sunjincheng121 commented on a diff in the pull request:
https://github.com/apache/flink/pull/5295#discussion_r161800866
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/assigners/SessionWindowTimeGapExtractor.java
---
@@ -0,0 +1,30 @@
+/*
+ * 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.streaming.api.windowing.assigners;
+
+import java.io.Serializable;
+
+/**
+ * A {@code SessionWindowTimeGapExtractor} extracts session time gaps for
Dynamic Session Window Assigners.
+ *
+ * @param <T> The type of elements that this {@code
SessionWindowTimeGapExtractor} can extract session time gaps from.
+ */
+public interface SessionWindowTimeGapExtractor<T> extends Serializable {
+ long extract(T element, long timestamp,
WindowAssigner.WindowAssignerContext context);
--- End diff --
Can we remove the parameter of `timestamp` and
`WindowAssigner.WindowAssignerContext context`?
---
