@PublicEvolving public final class NullType extends LogicalType
NULL
values. The null type is an extension to the
SQL standard. A null type has no other value except NULL
, thus, it can be cast to any
nullable type similar to JVM semantics.
This type helps in representing unknown types in API calls that use a NULL
literal as
well as bridging to formats such as JSON or Avro that define such a type as well.
The serialized string representation is NULL
.
Note: The runtime does not support this type. It is a pure helper type during translation and planning. Table columns cannot be declared with this type. Functions cannot declare return types of this type.
Constructor and Description |
---|
NullType() |
Modifier and Type | Method and Description |
---|---|
<R> R |
accept(LogicalTypeVisitor<R> visitor) |
String |
asSerializableString()
Returns a string that fully serializes this instance.
|
LogicalType |
copy(boolean isNullable)
Returns a deep copy of this type with possibly different nullability.
|
List<LogicalType> |
getChildren() |
Class<?> |
getDefaultConversion()
Returns the default conversion class.
|
boolean |
supportsInputConversion(Class<?> clazz)
Returns whether an instance of the given class can be represented as a value of this logical
type when entering the table ecosystem.
|
boolean |
supportsOutputConversion(Class<?> clazz)
Returns whether a value of this logical type can be represented as an instance of the given
class when leaving the table ecosystem.
|
asSummaryString, conversionSet, copy, equals, getTypeRoot, hashCode, is, is, isAnyOf, isAnyOf, isNullable, toString, withNullability
public LogicalType copy(boolean isNullable)
LogicalType
copy
in class LogicalType
isNullable
- the intended nullability of the copied typepublic String asSerializableString()
LogicalType
See LogicalTypeParser
for the reverse operation.
asSerializableString
in class LogicalType
public boolean supportsInputConversion(Class<?> clazz)
LogicalType
A supported conversion directly maps an input class to a logical type without loss of precision or type widening.
For example, java.lang.Long
or long
can be used as input for BIGINT
independent of the set nullability.
supportsInputConversion
in class LogicalType
clazz
- input class to be converted into this logical typeLogicalType.getDefaultConversion()
public boolean supportsOutputConversion(Class<?> clazz)
LogicalType
A supported conversion directly maps a logical type to an output class without loss of precision or type widening.
For example, java.lang.Long
or long
can be used as output for BIGINT
if the type is not nullable. If the type is nullable, only java.lang.Long
can
represent this.
supportsOutputConversion
in class LogicalType
clazz
- output class to be converted from this logical typeLogicalType.getDefaultConversion()
public Class<?> getDefaultConversion()
LogicalType
For example, java.lang.Long
is the default input and output for BIGINT
.
getDefaultConversion
in class LogicalType
LogicalType.supportsInputConversion(Class)
,
LogicalType.supportsOutputConversion(Class)
public List<LogicalType> getChildren()
getChildren
in class LogicalType
public <R> R accept(LogicalTypeVisitor<R> visitor)
accept
in class LogicalType
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