com.pervasive.datarush.functions

Interface FunctionTyper

All Known Implementing Classes:

FixedType, WidestInputTyper

public interface FunctionTyper

Determines the upper bound and result type of a ScalarValuedFunction. A number of implementations are provided which cover common use cases.

A FunctionTyper is used as part of a function description to provide type checking of arguments and to determine the type of the output buffer. Because descriptions are serialized within the framework, implementations of FunctionTyper must also be serializable as JSON.

See Also:

ScalarValuedFunction, ScalarFunctionDescriptor

Method Summary

Modifier and Type	Method and Description
ScalarTokenType	computeResultType(FunctionContext ctx) Calculates the result type for the function given the provided context.
ScalarTokenType	computeUpperBound(FunctionContext ctx) Calculates the upper bound for the function given the provided context.

Method Detail

computeUpperBound

ScalarTokenType computeUpperBound(FunctionContext ctx)

Calculates the upper bound for the function given the provided context.

The context contains the upper bounds on the types of all arguments to the function. If a argument is not a subclass of ScalarValuedFunction, its type is null.

Parameters:

ctx - the context of the function being processed

Returns:

the upper bound on the function

computeResultType

ScalarTokenType computeResultType(FunctionContext ctx)

Calculates the result type for the function given the provided context.

The context contains the actual result types of all arguments to the function. If a argument is not a subclass of ScalarValuedFunction, its type is null.

Parameters:

ctx - the context of the function being processed

Returns:

the result type of the function