Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/2761#discussion_r97658665
--- Diff:
flink-examples/flink-examples-streaming/src/main/scala/org/apache/flink/streaming/scala/examples/windowing/SessionWindowing.scala
---
@@ -0,0 +1,94 @@
+/*
+ * 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.scala.examples.windowing
+
+import org.apache.flink.api.java.utils.ParameterTool
+import org.apache.flink.api.scala._
+import org.apache.flink.streaming.api.TimeCharacteristic
+import org.apache.flink.streaming.api.functions.source.SourceFunction
+import
org.apache.flink.streaming.api.functions.source.SourceFunction.SourceContext
+import org.apache.flink.streaming.api.scala.StreamExecutionEnvironment
+import org.apache.flink.streaming.api.watermark.Watermark
+import
org.apache.flink.streaming.api.windowing.assigners.EventTimeSessionWindows
+import org.apache.flink.streaming.api.windowing.time.Time
+
+/**
+ * An example of grouped stream windowing in session windows with session
timeout of 3 msec.
+ * A source fetches elements with key, timestamp, and count.
+ */
+object SessionWindowing {
+
+ def main(args: Array[String]): Unit = {
+
+ val params = ParameterTool.fromArgs(args)
+ val env = StreamExecutionEnvironment.getExecutionEnvironment
+
+ env.getConfig.setGlobalJobParameters(params)
+ env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime)
+ env.setParallelism(1)
+
+ val fileOutput = params.has("output")
+
+ val input = List(
+ ("a", 1L, 1),
+ ("b", 1L, 1),
+ ("b", 3L, 1),
+ ("b", 5L, 1),
+ ("c", 6L, 1),
+ // We expect to detect the session "a" earlier than this point (the
old
+ // functionality can only detect here when the next starts)
+ ("a", 10L, 1),
+ // We expect to detect session "b" and "c" at this point as well
+ ("c", 11L, 1)
+ )
+
+ val source = env.addSource(new SourceFunction[(String, Long, Int)]() {
+
+ override def run(ctx: SourceContext[(String, Long, Int)]): Unit = {
+ input.foreach(value => {
+ ctx.collectWithTimestamp(value, value._2)
+ ctx.emitWatermark(new Watermark(value._2 - 1))
+ if (!fileOutput) {
--- End diff --
I'd remove this condition. Not sure how much value the printed values add
to the example.
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