com.pervasive.datarush.functions

Class FixedType

java.lang.Object

com.pervasive.datarush.functions.FixedType

All Implemented Interfaces:

FunctionTyper

public class FixedType
extends Object
implements FunctionTyper

A typer for functions which return a fixed, known type.

Constructor Summary

Constructors

Constructor and Description
FixedType(ScalarTokenType type) Creates a typer which always returns the given 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

FixedType

public FixedType(ScalarTokenType type)

Creates a typer which always returns the given type.

Parameters:

type - the return type of the function. This must not be an abstract type.

Throws:

IllegalArgumentException - if the type is not a valid return type for functions

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