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Posted to issues@iceberg.apache.org by GitBox <gi...@apache.org> on 2021/09/03 16:23:18 UTC
[GitHub] [iceberg] hililiwei commented on a change in pull request #2969: Flink:Add Flink Scala Api
hililiwei commented on a change in pull request #2969:
URL: https://github.com/apache/iceberg/pull/2969#discussion_r699386820
##########
File path: flink/src/main/java/org/apache/iceberg/flink/util/FlinkScalaUtil.java
##########
@@ -0,0 +1,36 @@
+/*
+ * 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.iceberg.flink.util;
+
+import org.apache.flink.streaming.api.scala.DataStream;
+
+public class FlinkScalaUtil {
+ private FlinkScalaUtil() {
+ }
+
+ /**
+ * Converts an [[org.apache.flink.streaming.api.datastream.DataStream]] to a
+ * [[org.apache.flink.streaming.api.scala.DataStream]].
+ */
+ public static <T> DataStream<T> asScalaStream(
+ org.apache.flink.streaming.api.datastream.DataStream<T> javaDataStream) {
+ return new DataStream<>(javaDataStream);
+ }
Review comment:
For example, there is a method named env in the FlinkSourcre class. The method signature includes a Java StreamExecutionEnvironment parameter. In order to prevent developers who use scala from explicitly converting the scala StreamExecutionEnvironment class to the java StreamExecutionEnvironment class, I use the subclass Builder to provide A method that contains the parameters of scala's StreamExecutionEnvironment
##########
File path: flink/src/main/java/org/apache/iceberg/flink/sink/FlinkSink.java
##########
@@ -117,7 +109,7 @@ public static Builder forRowData(DataStream<RowData> input) {
return new Builder().forRowData(input);
}
- public static class Builder {
+ public static class Builder<T extends Builder<T>> {
Review comment:
> I'm not quite sure I understand why this templating addition is needed. Could you help clarify that for me?
If don't add this templating, when the subclass Builder instance calls the parent Builder's method, it will return an instance of the parent Builder, and we won't be able to access the subclass Builer method.
##########
File path: flink/src/main/java/org/apache/iceberg/flink/util/FlinkScalaUtil.java
##########
@@ -0,0 +1,36 @@
+/*
+ * 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.iceberg.flink.util;
+
+import org.apache.flink.streaming.api.scala.DataStream;
+
+public class FlinkScalaUtil {
+ private FlinkScalaUtil() {
+ }
+
+ /**
+ * Converts an [[org.apache.flink.streaming.api.datastream.DataStream]] to a
+ * [[org.apache.flink.streaming.api.scala.DataStream]].
+ */
+ public static <T> DataStream<T> asScalaStream(
+ org.apache.flink.streaming.api.datastream.DataStream<T> javaDataStream) {
+ return new DataStream<>(javaDataStream);
+ }
Review comment:
In the code submitted this time, most of the changes are to allow developers to directly use variables such as StreamExecutionEnvironment and DataStream in scala in FlinkSourceScala or FlinkSinkScala, without the need to convert them to Java before using them. Of course, FlinkScalaUtil still provides the ability to convert java DataStream to scala.
##########
File path: flink/src/main/java/org/apache/iceberg/flink/util/FlinkScalaUtil.java
##########
@@ -0,0 +1,36 @@
+/*
+ * 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.iceberg.flink.util;
+
+import org.apache.flink.streaming.api.scala.DataStream;
+
+public class FlinkScalaUtil {
+ private FlinkScalaUtil() {
+ }
+
+ /**
+ * Converts an [[org.apache.flink.streaming.api.datastream.DataStream]] to a
+ * [[org.apache.flink.streaming.api.scala.DataStream]].
+ */
+ public static <T> DataStream<T> asScalaStream(
+ org.apache.flink.streaming.api.datastream.DataStream<T> javaDataStream) {
+ return new DataStream<>(javaDataStream);
+ }
Review comment:
Because scala was not introduced, I extend FlinkSource\FlinkSink Builder , added several methods to receive scala variables, and changed the parent build to use covariance. If you think this is unnecessary, or there are other better ways to receive scala variables, please let me know, thank you.
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