org.apache.flink.table.sources

Interface DefinedFieldMapping

All Known Implementing Classes:

Kafka010TableSource, Kafka011TableSource, KafkaTableSource, KafkaTableSourceBase, StreamSQLTestProgram.GeneratorTableSource

@PublicEvolving
public interface DefinedFieldMapping

The DefinedFieldMapping interface provides a mapping for the fields of the table schema (TableSource.getTableSchema() to fields of the physical produced data type TableSource.getProducedDataType() of a TableSource.

If a TableSource does not implement the DefinedFieldMapping interface, the fields of its TableSchema are mapped to the fields of its produced DataType by name.

If the fields cannot or should not be implicitly mapped by name, an explicit mapping can be provided by implementing this interface.

If a mapping is provided, all fields must be explicitly mapped.

Method Summary

Modifier and Type	Method and Description
Map<String,String>	getFieldMapping() Returns the mapping for the fields of the TableSource's TableSchema to the fields of its produced DataType.

Method Detail

getFieldMapping

@Nullable
Map<String,String> getFieldMapping()

Returns the mapping for the fields of the TableSource's TableSchema to the fields of its produced DataType.

The mapping is done based on field names, e.g., a mapping "name" -> "f1" maps the schema field "name" to the field "f1" of the produced data type, for example in this case the second field of a Tuple.

The returned mapping must map all fields (except proctime and rowtime fields) to the produced data type. It can also provide a mapping for fields which are not in the TableSchema to make fields in the physical DataType accessible for a TimestampExtractor.

Returns:

A mapping from TableSchema fields to DataType fields or null if no mapping is necessary.