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https://issues.apache.org/jira/browse/FLINK-8558?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16536999#comment-16536999
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ASF GitHub Bot commented on FLINK-8558:
---------------------------------------
Github user pnowojski commented on a diff in the pull request:
https://github.com/apache/flink/pull/6264#discussion_r200987026
--- Diff:
flink-connectors/flink-connector-kafka-0.10/src/main/java/org/apache/flink/streaming/connectors/kafka/Kafka010TableSource.java
---
@@ -18,48 +18,99 @@
package org.apache.flink.streaming.connectors.kafka;
-import org.apache.flink.annotation.PublicEvolving;
+import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.serialization.DeserializationSchema;
import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.streaming.connectors.kafka.config.StartupMode;
+import
org.apache.flink.streaming.connectors.kafka.internals.KafkaTopicPartition;
import org.apache.flink.table.api.TableSchema;
+import org.apache.flink.table.sources.RowtimeAttributeDescriptor;
import org.apache.flink.table.sources.StreamTableSource;
import org.apache.flink.types.Row;
+import java.util.List;
+import java.util.Map;
import java.util.Properties;
/**
* Kafka {@link StreamTableSource} for Kafka 0.10.
*/
-@PublicEvolving
-public abstract class Kafka010TableSource extends KafkaTableSource {
+@Internal
+public class Kafka010TableSource extends KafkaTableSource {
- // The deserialization schema for the Kafka records
- private final DeserializationSchema<Row> deserializationSchema;
+ /**
+ * Creates a Kafka 0.10 {@link StreamTableSource}.
+ *
+ * @param schema Schema of the produced table.
+ * @param proctimeAttribute Field name of the processing time
attribute, null if no
--- End diff --
This is kind of controversial topic. Generally speaking I suspect that Java
discourage to use `Optional` beside return values because we should use
`@Nullable` or not use any of them. However in projects that ignored
`@Nullable` annotation (such as Flink), it's virtually impossible to start
using them and thus using `Optional` is the only way to have a compiler control
over optional/nullable fields.
In this particular use case of "optional" arguments my preference hierarchy
is:
1. provide a builder for this class
2. provide alternative constructor without this argument
3. use `@Nullable` with enabled compile errors on incorrectly handled
`@Nullable` annotations
4. use `Optional`
...
1336. use `@Nullable` WITHOUT compile errors on incorrectly handled
`@Nullable` annotations
1337. use nullable argument without `@Nullable` annotation
two last options are for me out of the question, since `1337` is evil and
`1336` doesn't improve situation. Option `3` is sadly impossible for Flink.
The same logic applies for me to other use cases (like fields, return
values etc):
1. avoid nulls/optionals (for example via builders or named parameters with
default values)
2. use `@Nullable` with compiler errors
3. use `Optional`
> Add unified format interfaces and format discovery
> --------------------------------------------------
>
> Key: FLINK-8558
> URL: https://issues.apache.org/jira/browse/FLINK-8558
> Project: Flink
> Issue Type: New Feature
> Components: Streaming Connectors
> Reporter: Timo Walther
> Assignee: Timo Walther
> Priority: Major
> Labels: pull-request-available
>
> In the last release, we introduced a new module {{flink-formats}}. Currently
> only {{flink-avro}} is located there but we will add more formats such as
> {{flink-json}}, {{flink-protobuf}}, and so on. For better separation of
> concerns we want decouple connectors from formats: e.g., remove
> {{KafkaAvroTableSource}} and {{KafkaJsonTableSource}}.
> A newly introduced {{FormatFactory}} will use Java service loaders to
> discovery available formats in the classpath (similar to how file systems are
> discovered now). A {{Format}} will provide a method for converting {{byte[]}}
> to target record type.
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