io.delta.kernel.types

Class MixedDataType

java.lang.Object

io.delta.kernel.types.DataType

io.delta.kernel.types.MixedDataType

public class MixedDataType
extends DataType

TODO: This is a controversial data type to have, but we have no way to specify the schema of JSON serialized table schema. In order to use the JsonHandler.parseJson(ColumnVector, StructType), the Kernel needs to specify the exact schema of the data, but depending upon the type serialized (`int` vs `map`), the serialized JSON could have different schema.

`int` type column schema is serialized as:

   {
     "name" : "a",
     "type" : "integer",
     "nullable" : false,
     "metadata" : { }
   }
  

`struct` type column schema is serialized as:

   {
     "name" : "b",
     "type" : {
       "type" : "struct",
       "fields" : [ {
         "name" : "d",
         "type" : "integer",
         "nullable" : false,
         "metadata" : { }
       } ]
     },
     "nullable" : true,
     "metadata" : { }
   }
 

Whenever this type is specified, reader should expect either a `string` value or `struct` value. The implementation of reader should convert the `string` or `struct` value to `string` type. Reader implementations can expect this type only for JSON format data reading cases only.

Field Summary

Fields

Modifier and Type	Field and Description
static MixedDataType	INSTANCE

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object obj)
int	hashCode()
java.lang.String	toJson() Convert the data type to Delta protocol specified serialization format.
java.lang.String	toString()

Methods inherited from class io.delta.kernel.types.DataType

equivalent

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

INSTANCE

public static final MixedDataType INSTANCE

Method Detail

toJson

public java.lang.String toJson()

Description copied from class: DataType

Convert the data type to Delta protocol specified serialization format.

Specified by:

toJson in class DataType

Returns:

Data type serialized in JSON format.

hashCode

public int hashCode()

Specified by:

hashCode in class DataType

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in class DataType

toString

public java.lang.String toString()

Specified by:

toString in class DataType