Package tools.refinery.interpreter.matchers.context

Interface IQueryRuntimeContext

All Known Implementing Classes:
AbstractQueryRuntimeContext
public interface IQueryRuntimeContext
Provides instance model information (relations corresponding to input keys) to query evaluator backends at runtime. Implementors shall extend AbstractQueryRuntimeContext instead directly this interface.

  • Method Details

    • getMetaContext

      IQueryMetaContext getMetaContext()
      Provides metamodel-specific info independent of the runtime instance model.

    • coalesceTraversals

      <V> V coalesceTraversals(Callable<V> callable) throws InvocationTargetException
      The given callable will be executed, and all model traversals will be delayed until the execution is done. If there are any outstanding information to be read from the model, a single coalesced model traversal will initialize the caches and deliver the notifications.

      Calls may be nested. A single coalesced traversal will happen at the end of the outermost call.

      Caution: results returned by the runtime context may be incomplete during the coalescing period, to be corrected by notifications sent during the final coalesced traversal. For example, if a certain input key is not cached yet, an empty relation may be reported during callable.call(); the cache will be constructed after the call terminates and notifications will deliver the entire content of the relation. Non-incremental query backends should therefore never enumerate input keys while coalesced (verify using isCoalescing()).

      Parameters:
      callable -
      Throws:
      InvocationTargetException

    • isCoalescing

      boolean isCoalescing()
      Returns:
      true iff currently within a coalescing section (i.e. within the callable of a call to coalesceTraversals(Callable)).

    • isIndexed

      boolean isIndexed(IInputKey key, IndexingService service)
      Returns true if index is available for the given key providing the given service.
      Throws:
      IllegalArgumentException - if key is not enumerable or an unknown type, see IQueryMetaContext.isEnumerable(IInputKey).
      Since:
      1.4

    • ensureIndexed

      void ensureIndexed(IInputKey key, IndexingService service)
      If the given (enumerable) input key is not yet indexed, the model will be traversed (after the end of the outermost coalescing block, see coalesceTraversals(Callable)) so that the index can be built. It is possible that the base indexer will select a higher indexing level merging multiple indexing requests to an appropriate level.

      Postcondition: After invoking this method,

      invalid reference 
      #getIndexed(IInputKey, IndexingService)
      for the same key and service will be guaranteed to return the requested or a highing indexing level as soon as isCoalescing() first returns false.

      Precondition: the given key is enumerable, see IQueryMetaContext.isEnumerable(IInputKey).

      Throws:
      IllegalArgumentException - if key is not enumerable or an unknown type, see IQueryMetaContext.isEnumerable(IInputKey).
      Since:
      1.4

    • countTuples

      int countTuples(IInputKey key, TupleMask seedMask, ITuple seed)
      Returns the number of tuples in the extensional relation identified by the input key seeded with the given mask and tuple.
      Parameters:
      key - an input key
      seedMask - a mask that extracts those parameters of the input key (from the entire parameter list) that should be bound to a fixed value; must not be null. Note: any given index must occur at most once in seedMask.
      seed - the tuple of fixed values restricting the match set to be considered, in the same order as given in parameterSeedMask, so that for each considered match tuple, projectedParameterSeed.equals(parameterSeedMask.transform(match)) should hold. Must not be null.
      Returns:
      the number of tuples in the model for the given key and seed

      Precondition: the given key is enumerable, see IQueryMetaContext.isEnumerable(IInputKey).

      Throws:
      IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
      Since:
      1.7

    • estimateCardinality

      Optional<Long> estimateCardinality(IInputKey key, TupleMask groupMask, Accuracy requiredAccuracy)
      Gives an estimate of the number of different groups the tuples of the given relation are projected into by the given mask (e.g. for an identity mask, this means the full relation size). The estimate must meet the required accuracy.

      Must accept any input key, even non-enumerables or those not recognized by this runtime context. If there is insufficient information to provide an answer up to the required precision, Optional.empty() is returned.

      PRE: TupleMask.isNonrepeating() must hold for the group mask.

      Returns:
      if available, an estimate of the cardinality of the projection of the given extensional relation, with the desired accuracy.
      Since:
      2.1

    • estimateAverageBucketSize

      default Optional<Double> estimateAverageBucketSize(IInputKey key, TupleMask groupMask, Accuracy requiredAccuracy)
      Gives an estimate of the average size of different groups the tuples of the given relation are projected into by the given mask (e.g. for an identity mask, this means 1, while for an empty mask, the result is the full relation size). The estimate must meet the required accuracy.

      Must accept any input key, even non-enumerables or those not recognized by this runtime context. If there is insufficient information to provide an answer up to the required precision, Optional.empty() may be returned.

      For an empty relation, zero is acceptable as an exact answer.

      PRE: TupleMask.isNonrepeating() must hold for the group mask.

      Returns:
      if available, an estimate of the average size of each projection group of the given extensional relation, with the desired accuracy.
      Since:
      2.1

    • enumerateTuples

      Iterable<Tuple> enumerateTuples(IInputKey key, TupleMask seedMask, ITuple seed)
      Returns the tuples in the extensional relation identified by the input key, optionally seeded with the given tuple.
      Parameters:
      key - an input key
      seedMask - a mask that extracts those parameters of the input key (from the entire parameter list) that should be bound to a fixed value; must not be null. Note: any given index must occur at most once in seedMask.
      seed - the tuple of fixed values restricting the match set to be considered, in the same order as given in parameterSeedMask, so that for each considered match tuple, projectedParameterSeed.equals(parameterSeedMask.transform(match)) should hold. Must not be null.
      Returns:
      the tuples in the model for the given key and seed

      Precondition: the given key is enumerable, see IQueryMetaContext.isEnumerable(IInputKey).

      Throws:
      IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
      Since:
      1.7

    • enumerateValues

      Iterable<? extends Object> enumerateValues(IInputKey key, TupleMask seedMask, ITuple seed)
      Simpler form of enumerateTuples(IInputKey, TupleMask, Tuple) in the case where all values of the tuples are bound by the seed except for one.

      Selects the tuples in the extensional relation identified by the input key, optionally seeded with the given tuple, and then returns the single value from each tuple which is not bound by the ssed mask.

      Parameters:
      key - an input key
      seedMask - a mask that extracts those parameters of the input key (from the entire parameter list) that should be bound to a fixed value; must not be null. Note: any given index must occur at most once in seedMask, and seedMask must include all parameters in any arbitrary order except one.
      seed - the tuple of fixed values restricting the match set to be considered, in the same order as given in parameterSeedMask, so that for each considered match tuple, projectedParameterSeed.equals(parameterSeedMask.transform(match)) should hold. Must not be null.
      Returns:
      the objects in the model for the given key and seed

      Precondition: the given key is enumerable, see IQueryMetaContext.isEnumerable(IInputKey).

      Throws:
      IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
      Since:
      1.7

    • containsTuple

      boolean containsTuple(IInputKey key, ITuple seed)
      Simpler form of enumerateTuples(IInputKey, TupleMask, Tuple) in the case where all values of the tuples are bound by the seed.

      Returns whether the given tuple is in the extensional relation identified by the input key.

      Note: this call works for non-enumerable input keys as well.

      Parameters:
      key - an input key
      seed - the tuple of fixed values restricting the match set to be considered, in the same order as given in parameterSeedMask, so that for each considered match tuple, projectedParameterSeed.equals(parameterSeedMask.transform(match)) should hold. Must not be null.
      Returns:
      true iff there is at least a single tuple contained in the relation that corresponds to the seed tuple
      Since:
      2.0

    • addUpdateListener

      void addUpdateListener(IInputKey key, Tuple seed, IQueryRuntimeContextListener listener)
      Subscribes for updates in the extensional relation identified by the input key, optionally seeded with the given tuple.

      This should be called after invoking

      Parameters:
      key - an input key
      seed - can be null or a tuple with matching arity; if non-null, only those updates in the model are notified about that match the seed at positions where the seed is non-null.
      listener - will be notified of future changes

      Precondition: the given key is enumerable, see IQueryMetaContext.isEnumerable(IInputKey).

      Throws:
      IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).

    • removeUpdateListener

      void removeUpdateListener(IInputKey key, Tuple seed, IQueryRuntimeContextListener listener)
      Unsubscribes from updates in the extensional relation identified by the input key, optionally seeded with the given tuple.
      Parameters:
      key - an input key
      seed - can be null or a tuple with matching arity; if non-null, only those updates in the model are notified about that match the seed at positions where the seed is non-null.
      listener - will no longer be notified of future changes

      Precondition: the given key is enumerable, see IQueryMetaContext.isEnumerable(IInputKey).

      Throws:
      IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).

    • wrapElement

      Object wrapElement(Object externalElement)
      Wraps the external element into the internal representation that is to be used by the query backend

      model element -> internal object.

      null must be mapped to null.

    • unwrapElement

      Object unwrapElement(Object internalElement)
      Unwraps the internal representation of the element into its original form

      internal object -> model element

      null must be mapped to null.

    • wrapTuple

      Tuple wrapTuple(Tuple externalElements)
      Unwraps the tuple of elements into the internal representation that is to be used by the query backend

      model elements -> internal objects

      null must be mapped to null.

    • unwrapTuple

      Tuple unwrapTuple(Tuple internalElements)
      Unwraps the tuple of internal representations of elements into their original forms

      internal objects -> model elements

      null must be mapped to null.

    • ensureWildcardIndexing

      void ensureWildcardIndexing(IndexingService service)
      Starts wildcard indexing for the given service. After this call, no registration is required for this IndexingService. a previously set wildcard level cannot be lowered, only extended.
      Since:
      1.4

    • executeAfterTraversal

      void executeAfterTraversal(Runnable runnable) throws InvocationTargetException
      Execute the given runnable after traversal. It is guaranteed that the runnable is executed as soon as the indexing is finished. The callback is executed only once, then is removed from the callback queue.
      Parameters:
      traversalCallback -
      Throws:
      InvocationTargetException
      Since:
      1.4

    • getCancellationToken

      default CancellationToken getCancellationToken()