IQueryRuntimeContext

All Known Implementing Classes:

AbstractQueryRuntimeContext, DynamicEMFQueryRuntimeContext, EMFQueryRuntimeContext
```
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.

No Implement:

This interface is not intended to be implemented by clients. Extend AbstractQueryRuntimeContext instead.

Method Summary

All Methods Instance Methods Abstract Methods Deprecated Methods
Modifier and Type	Method and Description
`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.
`<V> V`	`coalesceTraversals(java.util.concurrent.Callable<V> callable)` The given callable will be executed, and all model traversals will be delayed until the execution is done.
`boolean`	`containsTuple(IInputKey key, Tuple seed)` Simpler form of `enumerateTuples(IInputKey, Tuple)` in the case where all values of the tuples are bound by the seed.
`int`	`countTuples(IInputKey key, Tuple seed)` Returns the number of tuples in the extensional relation identified by the input key, optionally seeded with the given tuple.
`void`	`ensureIndexed(IInputKey key)` Deprecated. use ensureIndexed(IInputKey, IndexingServices) instead
`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.
`void`	`ensureWildcardIndexing(IndexingService service)` Starts wildcard indexing for the given service.
`java.lang.Iterable<Tuple>`	`enumerateTuples(IInputKey key, Tuple seed)` Returns the tuples in the extensional relation identified by the input key, optionally seeded with the given tuple.
`java.lang.Iterable<? extends java.lang.Object>`	`enumerateValues(IInputKey key, Tuple seed)` Simpler form of `enumerateTuples(IInputKey, Tuple)` in the case where all values of the tuples are bound by the seed except for one.
`void`	`executeAfterTraversal(java.lang.Runnable runnable)` Execute the given runnable after traversal.
`IQueryMetaContext`	`getMetaContext()` Provides metamodel-specific info independent of the runtime instance model.
`boolean`	`isCoalescing()`
`boolean`	`isIndexed(IInputKey key)` Deprecated. use `isIndexed(IInputKey, IndexingService)` instead
`boolean`	`isIndexed(IInputKey key, IndexingService service)` Returns true if index is available for the given key providing the given service.
`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.
`java.lang.Object`	`unwrapElement(java.lang.Object internalElement)` Unwraps the internal representation of the element into its original form
`Tuple`	`unwrapTuple(Tuple internalElements)` Unwraps the tuple of internal representations of elements into their original forms
`java.lang.Object`	`wrapElement(java.lang.Object externalElement)` Wraps the external element into the internal representation that is to be used by the query backend
`Tuple`	`wrapTuple(Tuple externalElements)` Unwraps the tuple of elements into the internal representation that is to be used by the query backend

- Method Detail
  - getMetaContext
```
IQueryMetaContext getMetaContext()
```
    Provides metamodel-specific info independent of the runtime instance model.
  - coalesceTraversals
```
<V> V coalesceTraversals(java.util.concurrent.Callable<V> callable)
                  throws java.lang.reflect.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:
    
    java.lang.reflect.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.
    
    Since:
    
    1.4
  - isIndexed
```
@Deprecated
boolean isIndexed(IInputKey key)
```
    Deprecated. use isIndexed(IInputKey, IndexingService) instead
    
    Returns:
    
    true iff the given input key is already indexed, and contents are available without costly model traversal.
  - 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, #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:
    
    java.lang.IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
    
    Since:
    
    1.4
  - ensureIndexed
```
@Deprecated
void ensureIndexed(IInputKey key)
```
    Deprecated. use ensureIndexed(IInputKey, IndexingServices) instead
    
    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.
    Postcondition: After invoking this method, isIndexed(IInputKey) for the same key will be guaranteed to return true as soon as isCoalescing() first returns false.
    Precondition: the given key is enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
    
    Throws:
    
    java.lang.IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
  - countTuples
```
int countTuples(IInputKey key,
                Tuple seed)
```
    Returns the number of tuples 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 tuples in the model are counted that match the seed at positions where the seed is non-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:
    
    java.lang.IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
  - enumerateTuples
```
java.lang.Iterable<Tuple> enumerateTuples(IInputKey key,
                                          Tuple seed)
```
    Returns the tuples 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 tuples in the model are enumerated that match the seed at positions where the seed is non-null.
    
    Returns:
    
    the tuples in the model for the given key and seed
    Precondition: the given key is enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
    
    Throws:
    
    java.lang.IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
  - enumerateValues
```
java.lang.Iterable<? extends java.lang.Object> enumerateValues(IInputKey key,
                                                               Tuple seed)
```
    Simpler form of enumerateTuples(IInputKey, 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 corresponds to the only null value in the seed.
    
    Parameters:
    
    key - an input key
    
    seed - can be null (if key is unary) or a tuple with matching arity; if non-null, only those tuples in the model are enumerated that match the seed at positions where the seed is non-null; the seed is null at exactly one position.
    
    Returns:
    
    the objects in the model for the given key and seed
    Precondition: the given key is enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
    
    Throws:
    
    java.lang.IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
  - containsTuple
```
boolean containsTuple(IInputKey key,
                      Tuple seed)
```
    Simpler form of enumerateTuples(IInputKey, 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 - a tuple with matching arity, consisting of non-null elements (null can be used in the 0-ary case).
    
    Returns:
    
    true iff the seed tuple is contained in the relation
  - 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:
    
    java.lang.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:
    
    java.lang.IllegalArgumentException - if key is not enumerable, see IQueryMetaContext.isEnumerable(IInputKey).
  - wrapElement
```
java.lang.Object wrapElement(java.lang.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
```
java.lang.Object unwrapElement(java.lang.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(java.lang.Runnable runnable)
                    throws java.lang.reflect.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:
    
    java.lang.reflect.InvocationTargetException
    
    Since:
    
    1.4

Interface IQueryRuntimeContext

Method Summary

Method Detail

getMetaContext

coalesceTraversals

isCoalescing

isIndexed

isIndexed

ensureIndexed

ensureIndexed

countTuples

enumerateTuples

enumerateValues

containsTuple

addUpdateListener

removeUpdateListener

wrapElement

unwrapElement

wrapTuple

unwrapTuple

ensureWildcardIndexing

executeAfterTraversal