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

Class MapType

java.lang.Object

org.apache.flink.table.types.logical.LogicalType

org.apache.flink.table.types.logical.MapType

All Implemented Interfaces:

Serializable

@PublicEvolving
public final class MapType
extends LogicalType

Logical type of an associative array that maps keys (including NULL) to values (including NULL). A map cannot contain duplicate keys; each key can map to at most one value. There is no restriction of key types; it is the responsibility of the user to ensure uniqueness. The map type is an extension to the SQL standard.

The serialized string representation is MAP<kt, vt> where kt is the logical type of the key elements and vt is the logical type of the value elements.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static String	FORMAT

Constructor Summary

Constructors

Constructor	Description
MapType(boolean isNullable, LogicalType keyType, LogicalType valueType)
MapType(LogicalType keyType, LogicalType valueType)

Method Summary

Modifier and Type	Method	Description
<R> R	accept(LogicalTypeVisitor<R> visitor)
String	asSerializableString()	Returns a string that fully serializes this instance.
String	asSummaryString()	Returns a string that summarizes this type for printing to a console.
LogicalType	copy(boolean isNullable)	Returns a deep copy of this type with possibly different nullability.
boolean	equals(Object o)
List<LogicalType>	getChildren()
Class<?>	getDefaultConversion()	Returns the default conversion class.
LogicalType	getKeyType()
LogicalType	getValueType()
int	hashCode()
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.

Methods inherited from class org.apache.flink.table.types.logical.LogicalType

conversionSet, copy, getTypeRoot, is, is, isAnyOf, isAnyOf, isNullable, toString, withNullability

Methods inherited from class java.lang.Object

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

Field Detail

FORMAT

public static final String FORMAT

See Also:

Constant Field Values

Constructor Detail

MapType

public MapType(boolean isNullable,
               LogicalType keyType,
               LogicalType valueType)

MapType

public MapType(LogicalType keyType,
               LogicalType valueType)

Method Detail

getKeyType

public LogicalType getKeyType()

getValueType

public LogicalType getValueType()

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

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

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

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:

LogicalType.getDefaultConversion()

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:

LogicalType.getDefaultConversion()

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:

LogicalType.supportsInputConversion(Class), LogicalType.supportsOutputConversion(Class)

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