org.eclipse.rdf4j.federated.cache

Interface SourceSelectionCache

All Known Implementing Classes:

SourceSelectionMemoryCache

public interface SourceSelectionCache

Describes a cache that can be used for SourceSelection to reduce the number of remote requests.

Author:

Andreas Schwarte

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	SourceSelectionCache.StatementSourceAssurance

Method Summary

Modifier and Type	Method and Description
SourceSelectionCache.StatementSourceAssurance	getAssurance(SubQuery subQuery, Endpoint endpoint) Ask the cache if a given endpoint can provide results for a SubQuery.
void	updateInformation(SubQuery subQuery, Endpoint endpoint, boolean hasStatements) Update the information for a given SubQuery and Endpoint.

Method Detail

getAssurance

SourceSelectionCache.StatementSourceAssurance getAssurance(SubQuery subQuery,
                                                           Endpoint endpoint)

Ask the cache if a given endpoint can provide results for a SubQuery.

Implementations may infer information by applying logical rules, e.g. if a cache knows that an endpoint can provide statements {s, foaf:name, "Alan"}, it can also provide results for {s, foaf:name, ?name}.

If a cache cannot provide information for the given arguments, it must return SourceSelectionCache.StatementSourceAssurance.POSSIBLY_HAS_STATEMENTS in order to trigger a remote check.

Parameters:

subQuery -

endpoint -

Returns:

the SourceSelectionCache.StatementSourceAssurance

updateInformation

void updateInformation(SubQuery subQuery,
                       Endpoint endpoint,
                       boolean hasStatements)

Update the information for a given SubQuery and Endpoint.

Implementations must make sure that any operations are thread-safe

Parameters:

subQuery -

endpoint -

hasStatements -