com.pervasive.datarush.functions

Class WidestInputTyper

java.lang.Object

com.pervasive.datarush.functions.WidestInputTyper

All Implemented Interfaces:

FunctionTyper

public class WidestInputTyper
extends Object
implements FunctionTyper

A typer determining the output type of a function based on the types of one or more inputs. If more than one input is used, the widest of the inputs is used.

Constructor Summary

Constructors

Constructor and Description
WidestInputTyper(int... indices) Defines a type using the specified inputs to determine the output type.
WidestInputTyper(ScalarTokenType bound, int... indices) Defines a type using the specified inputs to determine the output type.

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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

WidestInputTyper

public WidestInputTyper(int... indices)

Defines a type using the specified inputs to determine the output type.

Parameters:

indices - the input arguments to use to determine type. If none are supplied, all arguments are used.

WidestInputTyper

public WidestInputTyper(ScalarTokenType bound,
                        int... indices)

Defines a type using the specified inputs to determine the output type. The given type is the upper bound on the output type. While this also implies an upper bound on the selected inputs, an explicit bound should also be declared in the ScalarFunctionDescriptor.

Parameters:

bound - the upper bound for the function

indices - the input arguments to use to determine type. If none are supplied, all arguments are used.

Method Detail

computeUpperBound

public ScalarTokenType computeUpperBound(FunctionContext ctx)

Description copied from interface: FunctionTyper

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.

Specified by:

computeUpperBound in interface FunctionTyper

Parameters:

ctx - the context of the function being processed

Returns:

the upper bound on the function

computeResultType

public ScalarTokenType computeResultType(FunctionContext ctx)

Description copied from interface: FunctionTyper

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.

Specified by:

computeResultType in interface FunctionTyper

Parameters:

ctx - the context of the function being processed

Returns:

the result type of the function