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https://issues.apache.org/jira/browse/FLINK-3566?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15175770#comment-15175770
]
Gyula Fora commented on FLINK-3566:
-----------------------------------
Another example with KeySelectors and interfaces:
interface Event {
String getKey();
}
public static class MyEvent implements Event {
@Override
public String getKey() {
return "";
}
}
public static void main(String[] args) {
StreamExecutionEnvironment env =
StreamExecutionEnvironment.getExecutionEnvironment();
DataStream<MyEvent> events = env.fromElements(new MyEvent());
applyKeySelector(events);
}
private static <E extends Event> void applyKeySelector(DataStream<E>
events) {
events.keyBy(e -> e.getKey());
}
This gives a following exception: Input mismatch: Generic object type
'package.TypeTest.MyEvent' expected but was 'package.TypeTest.Event'.
> Input type validation often fails on custom TypeInfo implementations
> --------------------------------------------------------------------
>
> Key: FLINK-3566
> URL: https://issues.apache.org/jira/browse/FLINK-3566
> Project: Flink
> Issue Type: Bug
> Components: Type Serialization System
> Reporter: Gyula Fora
>
> Input type validation often fails when used with custom type infos. One
> example of this behaviour can be reproduced by creating a custom type info
> with our own field type:
> StreamExecutionEnvironment env =
> StreamExecutionEnvironment.getExecutionEnvironment();
> env.generateSequence(1, 10).map(new MapFunction<Long,
> Tuple1<Optional<Long>>>() {
> @Override
> public Tuple1<Optional<Long>> map(Long value) throws
> Exception {
> return Tuple1.of(Optional.of(value));
> }
> }).returns(new TupleTypeInfo<>(new
> OptionTypeInfo<Long>(BasicTypeInfo.LONG_TYPE_INFO)))
> .keyBy(new KeySelector<Tuple1<Optional<Long>>,
> Optional<Long>>() {
> @Override
> public Optional<Long>
> getKey(Tuple1<Optional<Long>> value) throws Exception {
> return value.f0;
> }
> });
> This will fail on Input type validation at the KeySelector (or any other
> function for example a mapper) with the following exception:
> Input mismatch: Basic type expected.
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