org.eclipse.incquery.runtime.matchers.planning.helpers

Class BuildHelper

java.lang.Object

org.eclipse.incquery.runtime.matchers.planning.helpers.BuildHelper

public class BuildHelper
extends java.lang.Object

Author:

Gabor Bergmann

Constructor Summary

Constructors

Constructor and Description
BuildHelper()

Method Summary

Modifier and Type	Method and Description
static boolean	areAllVariablesDetermined(SubPlan plan, java.util.Collection<PVariable> determining, IQueryMetaContext context)
static boolean	areVariablesDetermined(SubPlan plan, java.util.Collection<PVariable> determining, java.util.Collection<PVariable> determined, IQueryMetaContext context)
static void	finalCheck(PBody pSystem, SubPlan plan, IQueryMetaContext context) Verifies whether all constraints are enforced and exported parameters are present.
static PConstraint	getAnyUnenforcedConstraint(PBody pSystem, SubPlan plan) Finds an arbitrary constraint that is not enforced at the given plan.
static SubPlan	trimUnneccessaryVariables(SubPlanFactory planFactory, SubPlan plan, boolean onlyIfNotDetermined, IQueryMetaContext context) Reduces the number of tuples by trimming (existentially quantifying) the set of variables that are visible in the subplan, are not exported parameters, have all their constraints already enforced in the subplan, and thus will not be needed anymore.

Methods inherited from class java.lang.Object

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

Constructor Detail

BuildHelper

public BuildHelper()

Method Detail

trimUnneccessaryVariables

public static SubPlan trimUnneccessaryVariables(SubPlanFactory planFactory,
                                                SubPlan plan,
                                                boolean onlyIfNotDetermined,
                                                IQueryMetaContext context)

Reduces the number of tuples by trimming (existentially quantifying) the set of variables that

• are visible in the subplan,
• are not exported parameters,
• have all their constraints already enforced in the subplan,

and thus will not be needed anymore.

Parameters:

onlyIfNotDetermined - if true, no trimming performed unless there is at least one such variable

Returns:

the plan after the trimming (possibly the original)

areAllVariablesDetermined

public static boolean areAllVariablesDetermined(SubPlan plan,
                                                java.util.Collection<PVariable> determining,
                                                IQueryMetaContext context)

Returns:

true iff a set of given variables functionally determine all visible variables in the subplan according to the subplan's constraints

areVariablesDetermined

public static boolean areVariablesDetermined(SubPlan plan,
                                             java.util.Collection<PVariable> determining,
                                             java.util.Collection<PVariable> determined,
                                             IQueryMetaContext context)

Returns:

true iff one set of given variables functionally determine the other set according to the subplan's constraints

getAnyUnenforcedConstraint

public static PConstraint getAnyUnenforcedConstraint(PBody pSystem,
                                                     SubPlan plan)

Finds an arbitrary constraint that is not enforced at the given plan.

Parameters:

pSystem -

plan -

Returns:

a PConstraint that is not enforced, if any, or null if all are enforced

finalCheck

public static void finalCheck(PBody pSystem,
                              SubPlan plan,
                              IQueryMetaContext context)
                       throws QueryProcessingException

Verifies whether all constraints are enforced and exported parameters are present.

Parameters:

pSystem -

plan -

Throws:

QueryProcessingException