org.apache.flink.table.types.logical

类 MultisetType

java.lang.Object

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

org.apache.flink.table.types.logical.MultisetType

所有已实现的接口:

Serializable

@PublicEvolving
public final class MultisetType
extends LogicalType

Logical type of a multiset (=bag). Unlike a set, it allows for multiple instances for each of its elements with a common subtype. Each unique value (including NULL) is mapped to some multiplicity. There is no restriction of element types; it is the responsibility of the user to ensure uniqueness.

The serialized string representation is MULTISET<t> where t is the logical type of the contained elements. t MULTISET is a synonym for being closer to the SQL standard.

A conversion is possible through a map that assigns each value to an integer multiplicity (Map<t, Integer>).

另请参阅:

序列化表格

字段概要

字段

限定符和类型	字段和说明
static String	FORMAT

构造器概要

构造器

构造器和说明
MultisetType(boolean isNullable, LogicalType elementType)
MultisetType(LogicalType elementType)

方法概要

限定符和类型	方法和说明
<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	getElementType()
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.

从类继承的方法 org.apache.flink.table.types.logical.LogicalType

conversionSet, copy, getTypeRoot, isNullable, toString, withNullability

从类继承的方法 java.lang.Object

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

字段详细资料

FORMAT

public static final String FORMAT

另请参阅:

常量字段值

构造器详细资料

MultisetType

public MultisetType(boolean isNullable,
                    LogicalType elementType)

MultisetType

public MultisetType(LogicalType elementType)

方法详细资料

getElementType

public LogicalType getElementType()

copy

public LogicalType copy(boolean isNullable)

从类复制的说明: LogicalType

Returns a deep copy of this type with possibly different nullability.

指定者:

copy 在类中 LogicalType

参数:

isNullable - the intended nullability of the copied type

返回:

a deep copy

asSummaryString

public String asSummaryString()

从类复制的说明: 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.

覆盖:

asSummaryString 在类中 LogicalType

返回:

summary string of this type for debugging purposes

asSerializableString

public String asSerializableString()

从类复制的说明: 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.

指定者:

asSerializableString 在类中 LogicalType

返回:

detailed string for transmission or persistence

supportsInputConversion

public boolean supportsInputConversion(Class<?> clazz)

从类复制的说明: 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.

指定者:

supportsInputConversion 在类中 LogicalType

参数:

clazz - input class to be converted into this logical type

返回:

flag that indicates if instances of this class can be used as input into the table ecosystem

另请参阅:

LogicalType.getDefaultConversion()

supportsOutputConversion

public boolean supportsOutputConversion(Class<?> clazz)

从类复制的说明: 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.

指定者:

supportsOutputConversion 在类中 LogicalType

参数:

clazz - output class to be converted from this logical type

返回:

flag that indicates if instances of this class can be used as output from the table ecosystem

另请参阅:

LogicalType.getDefaultConversion()

getDefaultConversion

public Class<?> getDefaultConversion()

从类复制的说明: 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.

指定者:

getDefaultConversion 在类中 LogicalType

返回:

default class to represent values of this logical type

另请参阅:

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

getChildren

public List<LogicalType> getChildren()

指定者:

getChildren 在类中 LogicalType

accept

public <R> R accept(LogicalTypeVisitor<R> visitor)

指定者:

accept 在类中 LogicalType

equals

public boolean equals(Object o)

覆盖:

equals 在类中 LogicalType

hashCode

public int hashCode()

覆盖:

hashCode 在类中 LogicalType