Package org.apache.flink.table.types.logical

Class DistinctType

java.lang.Object
org.apache.flink.table.types.logical.LogicalType
org.apache.flink.table.types.logical.UserDefinedType
org.apache.flink.table.types.logical.DistinctType
All Implemented Interfaces:
Serializable
@PublicEvolving public final class DistinctType extends UserDefinedType
Logical type of a user-defined distinct type. A distinct type specifies an identifier and is backed by a source type. A distinct type has the same internal representation as a source type, but is considered to be a separate and incompatible data type for most operations. Compared to the SQL standard, every non-user-defined type can be used as a source type.

A distinct type can always be cast to its source type and vice versa.

Distinct types are implicitly final and do not support super types.

Most other properties are forwarded from the source type. Thus, ordering and comparison among the same distinct types are supported.

The serialized string representation is the fully qualified name of this type which means that the type must have been registered in a catalog.

See Also:

  • Method Details

    • newBuilder

      public static DistinctType.Builder newBuilder(ObjectIdentifier objectIdentifier, LogicalType sourceType)
      Creates a builder for a DistinctType.

    • getSourceType

      public LogicalType getSourceType()

    • copy

      public LogicalType copy(boolean isNullable)
      Description copied from class: LogicalType
      Returns a deep copy of this type with possibly different nullability.
      Specified by:
      copy in class LogicalType
      Parameters:
      isNullable - the intended nullability of the copied type
      Returns:
      a deep copy

    • supportsInputConversion

      public boolean supportsInputConversion(Class<?> clazz)
      Description copied from class: LogicalType
      Returns whether an instance of the given class can be represented as a value of this logical type when entering the table ecosystem. This method helps for the interoperability between JVM-based languages and the relational type system.

      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.

      Specified by:
      supportsInputConversion in class LogicalType
      Parameters:
      clazz - input class to be converted into this logical type
      Returns:
      flag that indicates if instances of this class can be used as input into the table ecosystem
      See Also:

    • supportsOutputConversion

      public boolean supportsOutputConversion(Class<?> clazz)
      Description copied from class: LogicalType
      Returns whether a value of this logical type can be represented as an instance of the given class when leaving the table ecosystem. This method helps for the interoperability between JVM-based languages and the relational type system.

      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.

      Specified by:
      supportsOutputConversion in class LogicalType
      Parameters:
      clazz - output class to be converted from this logical type
      Returns:
      flag that indicates if instances of this class can be used as output from the table ecosystem
      See Also:

    • getDefaultConversion

      public Class<?> getDefaultConversion()
      Description copied from class: LogicalType
      Returns the default conversion class. A value of this logical type is expected to be an instance of the given class when entering or is represented as an instance of the given class when leaving the table ecosystem if no other conversion has been specified.

      For example, java.lang.Long is the default input and output for BIGINT.

      Specified by:
      getDefaultConversion in class LogicalType
      Returns:
      default class to represent values of this logical type
      See Also:

    • getChildren

      public List<LogicalType> getChildren()
      Specified by:
      getChildren in class LogicalType

    • accept

      public <R> R accept(LogicalTypeVisitor<R> visitor)
      Specified by:
      accept in class LogicalType

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class UserDefinedType

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class UserDefinedType