value class type of flink mapstate

Question

I would like to declare a flink mapState as below which value type is a pojo arraylist, what should I set its value class type?

private transient MapState<String, List<pojo>> mapState;
mapState = getRuntimeContext().getMapState(
                new MapStateDescriptor<String, List<pojo>>(
                        "RIGHT_BUFFER",
                        String.class,
                        ???
                )
        );

it's not okay when I set value type to pojo.class or List.class . how to handle it?

Answer 1

private final MapStateDescriptor<String, List<Pojo>> mapStateDesc =
    new MapStateDescriptor<>(
        "RIGHT_BUFFER",
        BasicTypeInfo.STRING_TYPE_INFO,
        new ListTypeInfo<>(Pojo.class));

Answer 2

You need to use TypeInformation with TypeHint to handle generic classes. Something like:

        mapState = getRuntimeContext().getMapState(
                        new MapStateDescriptor<String, List<pojo>>(
                                "RIGHT_BUFFER",
                                TypeInformation.of(String.class),
                                TypeInformation.of(new TypeHint<List<pojo>>() {})
                        )
                );