[
https://issues.apache.org/jira/browse/FLINK-1159?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15163088#comment-15163088
]
ASF GitHub Bot commented on FLINK-1159:
---------------------------------------
Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/1704#discussion_r53945878
--- Diff:
flink-scala/src/main/scala/org/apache/flink/api/scala/extensions/acceptPartialFunctions/package.scala
---
@@ -0,0 +1,174 @@
+/*
+ * 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.api.scala.extensions
+
+import org.apache.flink.api.common.typeinfo.TypeInformation
+import org.apache.flink.api.scala._
+
+import scala.reflect.ClassTag
+
+/**
+ * acceptPartialFunctions extends the original DataSet with methods with
unique names
+ * that delegate to core higher-order functions (e.g. `map`) so that we
can work around
+ * the fact that overloaded methods taking functions as parameters can't
accept partial
+ * functions as well. This enables the possibility to directly apply
pattern matching
+ * to decompose inputs such as tuples, case classes and collections.
+ *
+ * e.g.
+ * {{{
+ * object Main {
+ * import org.apache.flink.api.scala.extensions._
+ * case class Point(x: Double, y: Double)
+ * def main(args: Array[String]): Unit = {
+ * val env = ExecutionEnvironment.getExecutionEnvironment
+ * val ds = env.fromElements(Point(1, 2), Point(3, 4), Point(5, 6))
+ * ds.filterWith {
+ * case Point(x, _) => x > 1
+ * }.reduceWith {
+ * case (Point(x1, y1), (Point(x2, y2))) => Point(x1 + y1, x2 +
y2)
+ * }.mapWith {
+ * case Point(x, y) => (x, y)
+ * }.flatMapWith {
+ * case (x, y) => Seq('x' -> x, 'y' -> y)
+ * }.groupingBy {
--- End diff --
Isn't it called `keyingBy`?
> Case style anonymous functions not supported by Scala API
> ---------------------------------------------------------
>
> Key: FLINK-1159
> URL: https://issues.apache.org/jira/browse/FLINK-1159
> Project: Flink
> Issue Type: Bug
> Components: Scala API
> Reporter: Till Rohrmann
> Assignee: Stefano Baghino
>
> In Scala it is very common to define anonymous functions of the following form
> {code}
> {
> case foo: Bar => foobar(foo)
> case _ => throw new RuntimeException()
> }
> {code}
> These case style anonymous functions are not supported yet by the Scala API.
> Thus, one has to write redundant code to name the function parameter.
> What works is the following pattern, but it is not intuitive for someone
> coming from Scala:
> {code}
> dataset.map{
> _ match{
> case foo:Bar => ...
> }
> }
> {code}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
