org.eclipse.incquery.runtime.matchers.context

Interface IQueryMetaContext

All Known Implementing Classes:

EMFQueryMetaContext

public interface IQueryMetaContext

Provides metamodel information (relationship of input keys) to query evaluator backends at runtime and at query planning time.

Author:

Bergmann Gabor

Method Summary

Modifier and Type	Method and Description
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 implications, e.g.
boolean	isEnumerable(IInputKey key) Returns true iff instance tuples of the given key can be enumerated.
boolean	isStateless(IInputKey key) Returns true iff the set of instance tuples of the given key is immutable.

Method Detail

isEnumerable

boolean isEnumerable(IInputKey key)

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().

isStateless

boolean isStateless(IInputKey key)

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

If false, the runtime provides notifications upon change.

getImplications

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

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

Note that for the obvious reasons, only enumerable keys can imply enumerable keys.

getFunctionalDependencies

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.

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