org.eclipse.viatra.query.runtime.emf

Class EMFQueryMetaContext

java.lang.Object

org.eclipse.viatra.query.runtime.matchers.context.AbstractQueryMetaContext

org.eclipse.viatra.query.runtime.emf.EMFQueryMetaContext

All Implemented Interfaces:

IQueryMetaContext

public final class EMFQueryMetaContext
extends AbstractQueryMetaContext

The meta context information for EMF scopes.

The runtime context may specialize answers with a given scope. In a static context, a conservative default version (DEFAULT) can be used instead.

TODO generics?

Field Summary

Fields

Modifier and Type	Field and Description
static EMFQueryMetaContext	DEFAULT Default static instance that only makes conservative assumptions that are valid for any scope.
static EMFQueryMetaContext	INSTANCE Deprecated. use DEFAULT

Method Summary

Modifier and Type	Method and Description
boolean	canLeadOutOfScope(IInputKey key) Tells whether the given IInputKey is an edge and may lead out of scope.
void	ensureValidKey(IInputKey key)
org.eclipse.emf.ecore.EReference	featureOpposite(org.eclipse.emf.ecore.EStructuralFeature typeObject)
org.eclipse.emf.ecore.EClass	featureSourceType(org.eclipse.emf.ecore.EStructuralFeature feature)
org.eclipse.emf.ecore.EClassifier	featureTargetType(org.eclipse.emf.ecore.EStructuralFeature typeObject)
com.google.common.collect.SetMultimap<InputKeyImplication,InputKeyImplication>	getConditionalImplications(IInputKey implyingKey) Returns known "double dispatch" implications, where the given implying key implies other input keys under certain additional conditions (themselves input keys).
java.util.Map<java.util.Set<java.lang.Integer>,java.util.Set<java.lang.Integer>>	getFunctionalDependencies(IInputKey key) Returns functional dependencies of the input key expressed in terms of column indices.
java.util.Collection<InputKeyImplication>	getImplications(IInputKey implyingKey) Returns known direct implications, e.g.
java.util.Comparator<IInputKey>	getSuggestedEliminationOrdering() For query normalizing, this is the order suggested for trying to eliminate input keys.
java.util.Collection<InputKeyImplication>	getWeakenedAlternatives(IInputKey implyingKey) Returns a set of implications (weakened alternatives), with a suggestion for the query planner that satisfying them first may help in satisfying the implying key.
void	illegalInputKey(IInputKey key)
boolean	isEnumerable(IInputKey key) Returns true iff instance tuples of the given key can be enumerated.
boolean	isFeatureMultiplicityOneTo(org.eclipse.emf.ecore.EStructuralFeature typeObject)
boolean	isFeatureMultiplicityToOne(org.eclipse.emf.ecore.EStructuralFeature feature)
boolean	isStateless(IInputKey key) Returns true iff the set of instance tuples of the given key is immutable.

Methods inherited from class org.eclipse.viatra.query.runtime.matchers.context.AbstractQueryMetaContext

getPosetComparator, isPosetKey

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT

public static final EMFQueryMetaContext DEFAULT

Default static instance that only makes conservative assumptions that are valid for any scope.

Since:

1.6

INSTANCE

@Deprecated
public static final EMFQueryMetaContext INSTANCE

Deprecated. use DEFAULT

Method Detail

isEnumerable

public boolean isEnumerable(IInputKey key)

Description copied from interface: IQueryMetaContext

Returns true iff instance tuples of the given key can be enumerated.

If false, the runtime can only test tuple membership in the extensional relation identified by the key, but not enumerate member tuples in general.

Equivalent to IInputKey.isEnumerable().

canLeadOutOfScope

public boolean canLeadOutOfScope(IInputKey key)

Description copied from interface: IQueryMetaContext

Tells whether the given IInputKey is an edge and may lead out of scope.

Specified by:

canLeadOutOfScope in interface IQueryMetaContext

Overrides:

canLeadOutOfScope in class AbstractQueryMetaContext

isStateless

public boolean isStateless(IInputKey key)

Description copied from interface: IQueryMetaContext

Returns true iff the set of instance tuples of the given key is immutable.

If false, the runtime provides notifications upon change.

getFunctionalDependencies

public java.util.Map<java.util.Set<java.lang.Integer>,java.util.Set<java.lang.Integer>> getFunctionalDependencies(IInputKey key)

Description copied from interface: IQueryMetaContext

Returns functional dependencies of the input key expressed in terms of column indices.

Each entry of the map is a functional dependency rule, where the entry key specifies source columns and the entry value specifies target columns.

getImplications

public java.util.Collection<InputKeyImplication> getImplications(IInputKey implyingKey)

Description copied from interface: IQueryMetaContext

Returns known direct implications, e.g. edge supertypes, edge opposites, node type constraints, etc.

Note that for the obvious reasons, enumerable keys can only be implied by enumerable keys.

getConditionalImplications

public com.google.common.collect.SetMultimap<InputKeyImplication,InputKeyImplication> getConditionalImplications(IInputKey implyingKey)

Description copied from interface: IQueryMetaContext

Returns known "double dispatch" implications, where the given implying key implies other input keys under certain additional conditions (themselves input keys). For example, a "type x, unscoped" input key may imply the "type x, in scope" input key under the condition of the input key "x is in scope"

Note that for the obvious reasons, enumerable keys can only be implied by enumerable keys (either as the implying key or as the additional condition).

Note that symmetry is not required, i.e. the additional conditions do not have to list the same conditional implication.

Specified by:

getConditionalImplications in interface IQueryMetaContext

Overrides:

getConditionalImplications in class AbstractQueryMetaContext

Returns:

multi-map, where the keys are additional conditions and the values are input key implications jointly implied by the condition and the given implying key.

getWeakenedAlternatives

public java.util.Collection<InputKeyImplication> getWeakenedAlternatives(IInputKey implyingKey)

Description copied from interface: IQueryMetaContext

Returns a set of implications (weakened alternatives), with a suggestion for the query planner that satisfying them first may help in satisfying the implying key.

Note that for the obvious reasons, enumerable keys can only be implied by enumerable keys.

Must follow directly or transitively from implications of IQueryMetaContext.getImplications(IInputKey).

Specified by:

getWeakenedAlternatives in interface IQueryMetaContext

Overrides:

getWeakenedAlternatives in class AbstractQueryMetaContext

ensureValidKey

public void ensureValidKey(IInputKey key)

illegalInputKey

public void illegalInputKey(IInputKey key)

isFeatureMultiplicityToOne

public boolean isFeatureMultiplicityToOne(org.eclipse.emf.ecore.EStructuralFeature feature)

isFeatureMultiplicityOneTo

public boolean isFeatureMultiplicityOneTo(org.eclipse.emf.ecore.EStructuralFeature typeObject)

featureSourceType

public org.eclipse.emf.ecore.EClass featureSourceType(org.eclipse.emf.ecore.EStructuralFeature feature)

featureTargetType

public org.eclipse.emf.ecore.EClassifier featureTargetType(org.eclipse.emf.ecore.EStructuralFeature typeObject)

featureOpposite

public org.eclipse.emf.ecore.EReference featureOpposite(org.eclipse.emf.ecore.EStructuralFeature typeObject)

getSuggestedEliminationOrdering

public java.util.Comparator<IInputKey> getSuggestedEliminationOrdering()

Description copied from interface: IQueryMetaContext

For query normalizing, this is the order suggested for trying to eliminate input keys.

Specified by:

getSuggestedEliminationOrdering in interface IQueryMetaContext

Overrides:

getSuggestedEliminationOrdering in class AbstractQueryMetaContext