org.deri.iris.builtins
Class FunctionalBuiltin

java.lang.Object
  org.deri.iris.builtins.AbstractBuiltin
      org.deri.iris.builtins.FunctionalBuiltin

All Implemented Interfaces:

Comparable<IAtom>, IAtom, IBuiltinAtom

Direct Known Subclasses:

ConversionBuiltin, DayFromDateBuiltin, DayFromDateTimeBuiltin, DayPartBuiltin, DaysFromDurationBuiltin, HourPartBuiltin, HoursFromDateTimeBuiltin, HoursFromDurationBuiltin, HoursFromTimeBuiltin, LangFromPlainLiteralBuiltin, MinutePartBuiltin, MinutesFromDateTimeBuiltin, MinutesFromDurationBuiltin, MinutesFromTimeBuiltin, MonthFromDateBuiltin, MonthFromDateTimeBuiltin, MonthPartBuiltin, MonthsFromDurationBuiltin, PlainLiteralCompareBuiltin, PlainLiteralFromStringBuiltin, PlainLiteralFromStringLangBuiltin, PlainLiteralLengthBuiltin, SecondPartBuiltin, SecondsFromDateTimeBuiltin, SecondsFromDurationBuiltin, SecondsFromTimeBuiltin, StringCompareBuiltin, StringConcatBuiltin, StringEscapeHtmlUriBuiltin, StringFromPlainLiteralBuiltin, StringIriToUriBuiltin, StringJoinBuiltin, StringLengthBuiltin, StringReplaceBuiltin, StringReplaceWithoutFlagsBuiltin, StringSubstringAfterBuiltin, StringSubstringAfterWithoutCollationBuiltin, StringSubstringBeforeBuiltin, StringSubstringBeforeWithoutCollationBuiltin, StringSubstringBuiltin, StringSubstringUntilEndBuiltin, StringToLowerBuiltin, StringToUpperBuiltin, StringUriEncodeBuiltin, TimezoneFromDateBuiltin, TimezoneFromDateTimeBuiltin, TimezoneFromTimeBuiltin, TimezonePartBuiltin, YearFromDateBuiltin, YearFromDateTimeBuiltin, YearPartBuiltin, YearsFromDurationBuiltin

public abstract class FunctionalBuiltin
extends AbstractBuiltin

Base class of functional built-in predicates. For this kind of built-in, the following properties must hold:

1. Can have any arity.
2. Can be evaluated with up to 1 unknown variable.
3. The unknown variable only occurs at the last position of the tuple.
4. If all terms are known at evaluation time, the given term is checked against the computed term to indicate true or false .

Field Summary

Fields inherited from class org.deri.iris.builtins.AbstractBuiltin

EMPTY_TERM

Constructor Summary

FunctionalBuiltin(IPredicate predicate, ITerm... terms)
Creates a new functional builtin.

Method Summary

protected abstract ITerm	computeResult(ITerm[] terms) Computes the result when all terms but the term at the last position are known.
protected ITerm	evaluateTerms(ITerm[] terms, int[] variableIndexes) Evaluate the predicate once the terms and variable indexes have been found.
int	maxUnknownVariables() The maximum number of unknown variables allowed such that the predicate can still be evaluated.
protected boolean	testForEquality(ITerm term1, ITerm term2) Tests for equality of two terms.

Methods inherited from class org.deri.iris.builtins.AbstractBuiltin

compareTo, equals, evaluate, getPredicate, getTuple, hashCode, isBuiltin, isGround, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

FunctionalBuiltin

public FunctionalBuiltin(IPredicate predicate,
                         ITerm... terms)

Creates a new functional builtin.

Parameters:

predicate - The predicate that identifies this built-in.

terms - The terms of the instance.

Method Detail

evaluateTerms

protected ITerm evaluateTerms(ITerm[] terms,
                              int[] variableIndexes)
                       throws EvaluationException

Description copied from class: AbstractBuiltin

Evaluate the predicate once the terms and variable indexes have been found.

Overrides:

evaluateTerms in class AbstractBuiltin

Parameters:

terms - The array of all terms for this evaluation.

variableIndexes - the indexes of the terms which should be computed (starting at 0)

Returns:

The result of the evaluation.

Throws:

EvaluationException

testForEquality

protected boolean testForEquality(ITerm term1,
                                  ITerm term2)

Tests for equality of two terms.

Parameters:

term1 - The first term.

term2 - The second term.

Returns:

true if both terms are equal, false otherwise.

computeResult

protected abstract ITerm computeResult(ITerm[] terms)
                                throws EvaluationException

Computes the result when all terms but the term at the last position are known.

Parameters:

terms - The terms, where the terms at the last position is a variable representing the result.

Returns:

The computed term, or null if the operation is unsuccessful.

Throws:

EvaluationException - If an error occurs.

maxUnknownVariables

public int maxUnknownVariables()

Description copied from interface: IBuiltinAtom

The maximum number of unknown variables allowed such that the predicate can still be evaluated.

Specified by:

maxUnknownVariables in interface IBuiltinAtom

Overrides:

maxUnknownVariables in class AbstractBuiltin

Returns:

The maximum number of unknown variables.