sunjincheng121 commented on a change in pull request #7437: [FLINK-11278]
[docs] Add documentation for TableAPI&SQL in scala-shell
URL: https://github.com/apache/flink/pull/7437#discussion_r246272212
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File path: docs/ops/scala_shell.md
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@@ -85,6 +86,113 @@ Note, that in the Streaming case, the print operation does
not trigger execution
The Flink Shell comes with command history and auto-completion.
+### Table API
+
+The example below is a wordcount program using Table API:
+<div class="codetabs" markdown="1">
+<div data-lang="stream" markdown="1">
+{% highlight scala %}
+Scala-Flink> import org.apache.flink.table.functions.TableFunction
+Scala-Flink> val textSource = stenv.fromDataStream(
+ senv.fromElements(
+ "To be, or not to be,--that is the question:--",
+ "Whether 'tis nobler in the mind to suffer",
+ "The slings and arrows of outrageous fortune",
+ "Or to take arms against a sea of troubles,"),
+ 'text)
+Scala-Flink> class $Split extends TableFunction[String] {
+ def eval(s: String): Unit = {
+ s.toLowerCase.split("\\W+").foreach(collect)
+ }
+ }
+Scala-Flink> val split = new $Split
+Scala-Flink> textSource.join(split('text) as 'word).
+ groupBy('word).select('word, 'word.count as 'count).
+ toRetractStream[(String, Long)].print
+Scala-Flink> senv.execute("Table Wordcount")
+{% endhighlight %}
+</div>
+<div data-lang="batch" markdown="1">
+{% highlight scala %}
+Scala-Flink> import org.apache.flink.table.functions.TableFunction
+Scala-Flink> val textSource = btenv.fromDataSet(
+ benv.fromElements(
+ "To be, or not to be,--that is the question:--",
+ "Whether 'tis nobler in the mind to suffer",
+ "The slings and arrows of outrageous fortune",
+ "Or to take arms against a sea of troubles,"),
+ 'text)
+Scala-Flink> class $Split extends TableFunction[String] {
+ def eval(s: String): Unit = {
+ s.toLowerCase.split("\\W+").foreach(collect)
+ }
+ }
+Scala-Flink> val split = new $Split
+Scala-Flink> textSource.join(split('text) as 'word).
+ groupBy('word).select('word, 'word.count as 'count).
+ toDataSet[(String, Long)].print
+{% endhighlight %}
+</div>
+</div>
+
+Note, that the $ prefix of the TableFunction classname is a walkaround of a
scala issue about incorrectly generated inner class name.
Review comment:
How about `Note, that using $ as a prefix for the class name of
TableFunction is a workaround of the issue that scala incorrectly generated
inner class name.` ?
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