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

Class VarCharType

java.lang.Object
org.apache.flink.table.types.logical.LogicalType
org.apache.flink.table.types.logical.VarCharType
All Implemented Interfaces:
Serializable
@PublicEvolving public final class VarCharType extends LogicalType
Logical type of a variable-length character string.

The serialized string representation is VARCHAR(n) where n is the maximum number of code points. n must have a value between 1 and Integer.MAX_VALUE (both inclusive). If no length is specified, n is equal to 1. STRING is a synonym for VARCHAR(2147483647).

For enabling type inference of a zero-length character string literal to a variable-length character string, this type does also support n to be 0. However, this is not exposed through the API.

A conversion from and to byte[] assumes UTF-8 encoding.

See Also:

  • Field Details

  • Constructor Details

    • VarCharType

      public VarCharType(boolean isNullable, int length)

    • VarCharType

      public VarCharType(int length)

    • VarCharType

      public VarCharType()

  • Method Details

    • ofEmptyLiteral

      public static VarCharType ofEmptyLiteral()
      The SQL standard defines that character string literals are allowed to be zero-length strings (i.e., to contain no characters) even though it is not permitted to declare a type that is zero. This has also implications on variable-length character strings during type inference because any fixed-length character string should be convertible to a variable-length one.

      This method enables this special kind of character string.

      Zero-length character strings have no serializable string representation.

    • getLength

      public int getLength()

    • 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

    • asSerializableString

      public String asSerializableString()
      Description copied from class: LogicalType
      Returns a string that fully serializes this instance. The serialized string can be used for transmitting or persisting a type.

      See LogicalTypeParser for the reverse operation.

      Specified by:
      asSerializableString in class LogicalType
      Returns:
      detailed string for transmission or persistence

    • asSummaryString

      public String asSummaryString()
      Description copied from class: LogicalType
      Returns a string that summarizes this type for printing to a console. An implementation might shorten long names or skips very specific properties.

      Use LogicalType.asSerializableString() for a type string that fully serializes this instance.

      Overrides:
      asSummaryString in class LogicalType
      Returns:
      summary string of this type for debugging purposes

    • 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 LogicalType

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class LogicalType