Package org.apache.flink.table.types.inference

Class StaticArgument

java.lang.Object

org.apache.flink.table.types.inference.StaticArgument

@PublicEvolving
public class StaticArgument
extends Object

Describes an argument in a static signature that is not overloaded and does not support varargs.

Static arguments are a special case of an input type strategy. While built-in functions often require advanced type inference strategies (taking data type families, common type constraints between arguments, customized validation), many functions are fine with a static signature. Static arguments power these basic use cases.

Static arguments can take tables, models, or scalar values. Each argument takes a set of StaticArgumentTrait that enable basic validation by the framework.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
Optional<Class<?>>	getConversionClass()
Optional<DataType>	getDataType()
String	getName()
EnumSet<StaticArgumentTrait>	getTraits()
int	hashCode()
boolean	is(StaticArgumentTrait trait)
boolean	isOptional()
static StaticArgument	scalar(String name, DataType dataType, boolean isOptional)	Declares a scalar argument such as f(12) or f(otherColumn).
static StaticArgument	table(String name, Class<?> conversionClass, boolean isOptional, EnumSet<StaticArgumentTrait> traits)	Declares a table argument such as f(t => myTable) or f(t => TABLE myTable)).
static StaticArgument	table(String name, DataType dataType, boolean isOptional, EnumSet<StaticArgumentTrait> traits)	Declares a table argument such as f(t => myTable) or f(t => TABLE myTable)).
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

scalar

public static StaticArgument scalar(String name,
                                    DataType dataType,
                                    boolean isOptional)

Declares a scalar argument such as f(12) or f(otherColumn).

Parameters:

name - name for the assignment operator e.g. f(myArg => 12)

dataType - explicit type to which the argument is cast if necessary

isOptional - whether the argument is optional, if optional the corresponding data type must be nullable

table

public static StaticArgument table(String name,
                                   Class<?> conversionClass,
                                   boolean isOptional,
                                   EnumSet<StaticArgumentTrait> traits)

Declares a table argument such as f(t => myTable) or f(t => TABLE myTable)).

The argument can have StaticArgumentTrait.ROW_SEMANTIC_TABLE (default) or StaticArgumentTrait.SET_SEMANTIC_TABLE semantics.

By only providing a conversion class, the argument supports a "polymorphic" behavior. In other words: it accepts tables with an arbitrary number of columns with arbitrary data types. For this case, a class satisfying RowType.supportsOutputConversion(Class) must be used.

Parameters:

name - name for the assignment operator e.g. f(myArg => 12)

conversionClass - a class satisfying RowType.supportsOutputConversion(Class)

isOptional - whether the argument is optional

traits - set of StaticArgumentTrait requiring StaticArgumentTrait.TABLE

table

public static StaticArgument table(String name,
                                   DataType dataType,
                                   boolean isOptional,
                                   EnumSet<StaticArgumentTrait> traits)

Declares a table argument such as f(t => myTable) or f(t => TABLE myTable)).

The argument can have StaticArgumentTrait.ROW_SEMANTIC_TABLE (default) or StaticArgumentTrait.SET_SEMANTIC_TABLE semantics.

By providing a concrete data type, the argument only accepts tables with corresponding number of columns and data types. The data type must be a RowType or StructuredType.

Parameters:

name - name for the assignment operator e.g. f(myArg => 12)

dataType - explicit type to which the argument is cast if necessary

isOptional - whether the argument is optional, if optional the corresponding data type must be nullable

traits - set of StaticArgumentTrait requiring StaticArgumentTrait.TABLE

getName

public String getName()

getDataType

public Optional<DataType> getDataType()

getConversionClass

public Optional<Class<?>> getConversionClass()

isOptional

public boolean isOptional()

getTraits

public EnumSet<StaticArgumentTrait> getTraits()

is

public boolean is(StaticArgumentTrait trait)

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object