Package dev.frostlake.functions.scalar.context

Class ProjectionConstraint

java.lang.Object

dev.frostlake.functions.BuiltInFunction

dev.frostlake.functions.scalar.context.ProjectionConstraint

public class ProjectionConstraint
extends BuiltInFunction

PROJECTION_CONSTRAINT(ALLOW => <boolean>) — what a PROJECTION POLICY's body returns. It is an ordinary callable function, not policy-only syntax: live answers {"allow":true,"enforcement":"FAIL"} for a bare SELECT PROJECTION_CONSTRAINT(ALLOW => TRUE) (unlike AGGREGATION_CONSTRAINT, which refuses to be called outside a policy body).

The argument MUST be named — the positional call is refused, in a query and inside a policy body alike — and that refusal is raised by the evaluator, which is where argument names are still known.

Constructor Summary

Constructors

Constructor	Description
ProjectionConstraint()

Method Summary

Modifier and Type	Method	Description
Object	evaluate(List<Object> args)	Computes the function's result over its already-evaluated argument values.
int	getMaxArgCount()	The most arguments a call to this function may pass; Integer.MAX_VALUE marks a variadic function (see BuiltInFunction.isVariadic()).
int	getMinArgCount()	The fewest arguments a call to this function may pass; fewer is an argument-count error.

Methods inherited from class dev.frostlake.functions.BuiltInFunction

approximateRejection, binaryRejection, booleanRejection, evaluate, fileRejection, geoRejection, getName, getReturnType, isVariadic, refusesMissingArgumentsByType, semiStructuredRejection, structuredRejection, temporalRejection, temporalRejection, temporalRejection, textRejection, uuidRejection, vectorRejection

Methods inherited from class java.lang.Object

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

Constructor Details

ProjectionConstraint

public ProjectionConstraint()

Method Details

getMinArgCount

public int getMinArgCount()

Description copied from class: BuiltInFunction

The fewest arguments a call to this function may pass; fewer is an argument-count error.

Specified by:

getMinArgCount in class BuiltInFunction

Returns:

the minimum accepted argument count

getMaxArgCount

public int getMaxArgCount()

Description copied from class: BuiltInFunction

The most arguments a call to this function may pass; Integer.MAX_VALUE marks a variadic function (see BuiltInFunction.isVariadic()).

Specified by:

getMaxArgCount in class BuiltInFunction

Returns:

the maximum accepted argument count

evaluate

public Object evaluate(List<Object> args)

Description copied from class: BuiltInFunction

Computes the function's result over its already-evaluated argument values. A SQL NULL argument arrives as Java null, and returning null makes the SQL result NULL.

Specified by:

evaluate in class BuiltInFunction

Parameters:

args - the argument values, in call order

Returns:

the function's value for these arguments, or null for SQL NULL