org.deri.iris.optimisations.rulefilter
Class RuleFilter

java.lang.Object
  org.deri.iris.optimisations.rulefilter.RuleFilter

All Implemented Interfaces:

IProgramOptimisation

public class RuleFilter
extends Object
implements IProgramOptimisation

Methods to shrink rules to the absolute minimum of needed rules.

Author:

Richard P??ttler (richard dot poettler at deri dot at)

Nested Class Summary

Nested classes/interfaces inherited from interface org.deri.iris.api.IProgramOptimisation

IProgramOptimisation.Result

Constructor Summary

RuleFilter()

Method Summary

static Set<IPredicate>	getDepends(Collection<IRule> r, IQuery q) Determines which predicates must be evaluated to evaluate a given query.
static Set<IRule>	getRulesForPredicates(Collection<IRule> r, Collection<IPredicate> p) Filters a set of rules so that it only contains rules defining a predicate out of a set of predicates.
IProgramOptimisation.Result	optimise(Collection<IRule> rules, IQuery query) Applies the optimisation algorithm to a set of rules.
static Set<IRule>	shrinkRules(Collection<IRule> r, IQuery q) Shrinks a set of rules to the absolute minimum of needed rules to evaluate a given query.

Methods inherited from class java.lang.Object

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

Constructor Detail

RuleFilter

public RuleFilter()

Method Detail

optimise

public IProgramOptimisation.Result optimise(Collection<IRule> rules,
                                            IQuery query)

Description copied from interface: IProgramOptimisation

Applies the optimisation algorithm to a set of rules. A Result which contains the transformed rules and the adjusted query.

Specified by:

optimise in interface IProgramOptimisation

Parameters:

rules - the rules to transform

query - the query for which to transform the rules

Returns:

a optimisation result or null, if the transformation failed.

shrinkRules

public static Set<IRule> shrinkRules(Collection<IRule> r,
                                     IQuery q)

Shrinks a set of rules to the absolute minimum of needed rules to evaluate a given query.

Parameters:

r - the rules to shrink

q - the query for which to shrink the rules

Returns:

the minimal set of needed rules

Throws:

NullPointerException - if the set of rules is null

NullPointerException - if the query is null

getRulesForPredicates

public static Set<IRule> getRulesForPredicates(Collection<IRule> r,
                                               Collection<IPredicate> p)

Filters a set of rules so that it only contains rules defining a predicate out of a set of predicates.

Parameters:

r - the rules to filter

p - the predicate for which to filter the rules

Returns:

the filtered rules

Throws:

NullPointerException - if the rules are null

NullPointerException - if the predicates are null

getDepends

public static Set<IPredicate> getDepends(Collection<IRule> r,
                                         IQuery q)

Determines which predicates must be evaluated to evaluate a given query.

Parameters:

r - the rules on which to determine on which predicate the query depends

q - the query for which to check the predicates

Returns:

the predicates the query depends on

Throws:

NullPointerException - if the set of rules is null

NullPointerException - if the query is null