StructuredType (Flink : Table : Common 1.12.5 API)

java.lang.Object
- org.apache.flink.table.types.logical.LogicalType
- - org.apache.flink.table.types.logical.UserDefinedType
  - - org.apache.flink.table.types.logical.StructuredType

所有已实现的接口:

Serializable
```
@PublicEvolving
public final class StructuredType
extends UserDefinedType
```
Logical type of a user-defined object structured type. Structured types contain zero, one or more attributes. Each attribute consists of a name and a type. A type cannot be defined so that one of its attribute types (transitively) uses itself.
There are two kinds of structured types. Types that are stored in a catalog and are identified by an ObjectIdentifier or anonymously defined, unregistered types (usually reflectively extracted) that are identified by an implementation Class.
Logical properties

A structured type can declare a super type and allows single inheritance for more complex type hierarchies, similar to JVM-based languages.
A structured type can be declared final for preventing further inheritance (default behavior) or not final for allowing subtypes.
A structured type can be declared not instantiable if a more specific type is required or instantiable if instances can be created from this type (default behavior).
A structured type declares comparision properties of either none (no equality), equals (only equality and inequality), or full (greater, equals, less).
NOTE: Compared to the SQL standard, this class is incomplete. We might add new features such as method declarations in the future. Also ordering is not supported yet.
Physical properties

A structured type can be defined fully logically (e.g. by using a CREATE TYPE DDL). The implementation class is optional and only used at the edges of the table ecosystem (e.g. when bridging to a function or connector). Serialization and equality (hashCode/equals) are handled by the runtime based on the logical type. In other words: hashCode/equals of an implementation class are not used. Custom equality, casting logic, and further overloaded operators will be supported once we allow defining methods on structured types.
An implementation class must offer a default constructor with zero arguments or a full constructor that assigns all attributes. Other physical properties such as the conversion classes of attributes are defined by a DataType when a structured type is used.

另请参阅:

序列化表格

嵌套类概要

嵌套类
限定符和类型	类和说明
`static class`	`StructuredType.Builder` A builder for a `StructuredType`.
`static class`	`StructuredType.StructuredAttribute` Defines an attribute of a `StructuredType`.
`static class`	`StructuredType.StructuredComparision` Defines equality properties for scalar evaluation.

方法概要

所有方法静态方法实例方法具体方法
限定符和类型	方法和说明
`<R> R`	`accept(LogicalTypeVisitor<R> visitor)`
`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<StructuredType.StructuredAttribute>`	`getAttributes()`
`List<LogicalType>`	`getChildren()`
`StructuredType.StructuredComparision`	`getComparision()`
`Class<?>`	`getDefaultConversion()` Returns the default conversion class.
`Optional<Class<?>>`	`getImplementationClass()`
`Optional<StructuredType>`	`getSuperType()`
`int`	`hashCode()`
`boolean`	`isInstantiable()`
`static StructuredType.Builder`	`newBuilder(Class<?> implementationClass)` Creates a builder for a `StructuredType` that is not stored in a catalog and is identified by an implementation `Class`.
`static StructuredType.Builder`	`newBuilder(ObjectIdentifier objectIdentifier)` Creates a builder for a `StructuredType` that has been stored in a catalog and is identified by an `ObjectIdentifier`.
`static StructuredType.Builder`	`newBuilder(ObjectIdentifier objectIdentifier, Class<?> implementationClass)` Creates a builder for a `StructuredType` that has been stored in a catalog and is identified by an `ObjectIdentifier`.
`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.UserDefinedType
asSerializableString, getDescription, getObjectIdentifier, isFinal

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

- 方法详细资料
  - newBuilder
```
public static StructuredType.Builder newBuilder(ObjectIdentifier objectIdentifier)
```
    Creates a builder for a StructuredType that has been stored in a catalog and is identified by an ObjectIdentifier.
  - newBuilder
```
public static StructuredType.Builder newBuilder(ObjectIdentifier objectIdentifier,
                                                Class<?> implementationClass)
```
    Creates a builder for a StructuredType that has been stored in a catalog and is identified by an ObjectIdentifier. The optional implementation class defines supported conversions.
  - newBuilder
```
public static StructuredType.Builder newBuilder(Class<?> implementationClass)
```
    Creates a builder for a StructuredType that is not stored in a catalog and is identified by an implementation Class.
  - getAttributes
```
public List<StructuredType.StructuredAttribute> getAttributes()
```
  - isInstantiable
```
public boolean isInstantiable()
```
  - getComparision
```
public StructuredType.StructuredComparision getComparision()
```
  - getSuperType
```
public Optional<StructuredType> getSuperType()
```
  - getImplementationClass
```
public Optional<Class<?>> getImplementationClass()
```
  - 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
  - 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 UserDefinedType
  - hashCode
```
public int hashCode()
```
    覆盖:
    
    hashCode 在类中 UserDefinedType

类 StructuredType

Logical properties

Physical properties

嵌套类概要

方法概要

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

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

从类继承的方法 java.lang.Object

方法详细资料

newBuilder

newBuilder

newBuilder

getAttributes

isInstantiable

getComparision

getSuperType

getImplementationClass

copy

asSummaryString

supportsInputConversion

supportsOutputConversion

getDefaultConversion

getChildren

accept

equals

hashCode