org.eclipse.incquery.runtime.matchers.backend

Interface IQueryResultProvider

All Known Implementing Classes:

LocalSearchResultProvider, RetePatternMatcher

public interface IQueryResultProvider

An internal interface of the query backend that provides results of a given query.

Author:

Bergmann Gabor

Method Summary

Modifier and Type	Method and Description
void	addUpdateListener(IUpdateable listener, java.lang.Object listenerTag, boolean fireNow) Internal method that registers low-level callbacks for match appearance and disappearance.
int	countMatches(java.lang.Object[] parameters) Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.
java.util.Collection<? extends Tuple>	getAllMatches(java.lang.Object[] parameters) Returns the set of all matches of the pattern that conform to the given fixed values of some parameters.
Tuple	getOneArbitraryMatch(java.lang.Object[] parameters) Returns an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
IQueryBackend	getQueryBackend() The underlying query evaluator backend.
void	removeUpdateListener(java.lang.Object listenerTag) Removes an existing listener previously registered with the given tag.

Method Detail

countMatches

int countMatches(java.lang.Object[] parameters)

Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.

Parameters:

parameters - array where each non-null element binds the corresponding pattern parameter to a fixed value.

Returns:

the number of pattern matches found.

getOneArbitraryMatch

Tuple getOneArbitraryMatch(java.lang.Object[] parameters)

Returns an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters. Neither determinism nor randomness of selection is guaranteed.

Parameters:

parameters - array where each non-null element binds the corresponding pattern parameter to a fixed value.

Returns:

a match represented in the internal Tuple representation.

getAllMatches

java.util.Collection<? extends Tuple> getAllMatches(java.lang.Object[] parameters)

Returns the set of all matches of the pattern that conform to the given fixed values of some parameters.

Parameters:

parameters - array where each non-null element binds the corresponding pattern parameter to a fixed value.

Returns:

matches represented in the internal Tuple representation.

getQueryBackend

IQueryBackend getQueryBackend()

The underlying query evaluator backend.

addUpdateListener

void addUpdateListener(IUpdateable listener,
                       java.lang.Object listenerTag,
                       boolean fireNow)

Internal method that registers low-level callbacks for match appearance and disappearance.

Caution: This is a low-level callback that is invoked when the pattern matcher is not necessarily in a consistent state yet. Importantly, no model modification permitted during the callback.

The callback can be unregistered via invoking removeUpdateListener(Object) with the same tag.

Parameters:

listener - the listener that will be notified of each new match that appears or disappears, starting from now.

listenerTag - a tag by which to identify the listener for later removal by removeUpdateListener(Object).

fireNow - if true, the insertion update allback will be immediately invoked on all current matches as a one-time effect.

Throws:

java.lang.UnsupportedOperationException - if this is a non-incremental backend (i.e. IQueryBackend.isCaching() on getQueryBackend() returns false)

removeUpdateListener

void removeUpdateListener(java.lang.Object listenerTag)

Removes an existing listener previously registered with the given tag.

Throws:

java.lang.UnsupportedOperationException - if this is a non-incremental backend (i.e. IQueryBackend.isCaching() on getQueryBackend() returns false)