Package org.eclipse.rdf4j.query.algebra.evaluation.federation

## Interface FederatedServiceResolver

- All Known Subinterfaces:
    `EvaluationStrategy`
  All Known Implementing Classes:
    `AbstractFederatedServiceResolver`, `DelegateFederatedServiceResolver`, `EvaluationStrategyImpl`, `ExtendedEvaluationStrategy`, `FederatedServiceResolverBase`, `FederationEvalStrategy`, `FederationStrategy`, `LimitedSizeEvaluationStrategy`, `SailFederationEvalStrategy`, `SimpleEvaluationStrategy`, `SparqlFederationEvalStrategy`, `SPARQLServiceResolver`, `StrictEvaluationStrategy`, `TupleFunctionEvaluationStrategy`

      public interface FederatedServiceResolver

  The `FederatedServiceResolver` is used to manage a set of `FederatedService` instances, which are used to evaluate SERVICE expressions for particular service Urls.

  Lookup can be done via the serviceUrl using the method `getService(String)`.

  Author:
    Andreas Schwarte, James Leigh

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `FederatedService` | `getService​(String serviceUrl)` | Retrieve the `FederatedService` registered for serviceUrl.

- - ### Method Detail

    - #### getService

          FederatedService getService​(String serviceUrl)
                               throws QueryEvaluationException

      Retrieve the `FederatedService` registered for serviceUrl. If there is no service registered for serviceUrl, a new `SPARQLFederatedService` is created and registered.
      Parameters:
        `serviceUrl` - locator for the federation service
      Returns:
        the `FederatedService`, created fresh if necessary
      Throws:
        `QueryEvaluationException` - If there was an exception generated while retrieving the service.