Package org.apache.cassandra.cql3.functions

Interface FunctionParameter

public interface FunctionParameter

Generic, loose definition of a function parameter, able to infer the specific data type of the parameter in the function specifically built by a FunctionFactory for a particular function call.

Method Summary

Modifier and Type	Method	Description
static FunctionParameter	anyCollection()
static FunctionParameter	anyMap()
static FunctionParameter	anyType(boolean inferFromReceiver)
static FunctionParameter	fixed(CQL3Type... types)
default AbstractType<?>	inferType(java.lang.String keyspace, AssignmentTestable arg, AbstractType<?> receiverType, java.util.List<AbstractType<?>> inferredTypes)	Tries to infer the data type of the parameter for an argument in a call to the function.
default boolean	isOptional()
static FunctionParameter	numericSetOrList()
static FunctionParameter	optional(FunctionParameter wrapped)
static FunctionParameter	sameAs(int index, boolean preferOther, FunctionParameter parameter)
static FunctionParameter	setOrList()
static FunctionParameter	string()
void	validateType(FunctionName name, AssignmentTestable arg, AbstractType<?> argType)
static FunctionParameter	vector(CQL3Type type)

Method Detail

inferType

@Nullable
default AbstractType<?> inferType(java.lang.String keyspace,
                                  AssignmentTestable arg,
                                  @Nullable
                                  AbstractType<?> receiverType,
                                  @Nullable
                                  java.util.List<AbstractType<?>> inferredTypes)

Tries to infer the data type of the parameter for an argument in a call to the function.

Parameters:

keyspace - the current keyspace

arg - a parameter value in a specific function call

receiverType - the type of the object that will receive the result of the function call

inferredTypes - the types that have been inferred for the other parameters

Returns:

the inferred data type of the parameter, or {@link null} it isn't possible to infer it

validateType

void validateType(FunctionName name,
                  AssignmentTestable arg,
                  AbstractType<?> argType)

isOptional

default boolean isOptional()

Returns:

whether this parameter is optional

optional

static FunctionParameter optional(FunctionParameter wrapped)

Parameters:

wrapped - the wrapped parameter

Returns:

a function parameter definition that accepts the specified wrapped parameter, considering it optional as defined by isOptional().

string

static FunctionParameter string()

Returns:

a function parameter definition that accepts values of string-based data types (text, varchar and ascii)

fixed

static FunctionParameter fixed(CQL3Type... types)

Parameters:

types - the accepted data types

Returns:

a function parameter definition that accepts values of a specific data type

anyType

static FunctionParameter anyType(boolean inferFromReceiver)

Parameters:

inferFromReceiver - whether the parameter should try to use the function receiver to infer its data type

Returns:

a function parameter definition that accepts columns of any data type

sameAs

static FunctionParameter sameAs(int index,
                                boolean preferOther,
                                FunctionParameter parameter)

Parameters:

index - the index of the function argument that this parameter is associated with

preferOther - whether the parameter should prefer the type of the other parameter over its own type

parameter - the type of this parameter when the type of the associated parameter is unknown

Returns:

a function parameter definition that is expected to have the same type as another parameter

anyCollection

static FunctionParameter anyCollection()

Returns:

a function parameter definition that accepts values of type CollectionType, independently of the types of its elements.

setOrList

static FunctionParameter setOrList()

Returns:

a function parameter definition that accepts values of type SetType or ListType.

numericSetOrList

static FunctionParameter numericSetOrList()

Returns:

a function parameter definition that accepts values of type SetType or ListType, provided that its elements are numeric.

anyMap

static FunctionParameter anyMap()

Returns:

a function parameter definition that accepts values of type MapType, independently of the types of the map keys and values.

vector

static FunctionParameter vector(CQL3Type type)

Parameters:

type - the type of the vector elements

Returns:

a function parameter definition that accepts values of type VectorType with elements of the specified type and any dimensions.