/*
* Copyright (c) 2010, Rickard Öberg. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.qi4j.api.service.importer;
import org.qi4j.api.injection.scope.Structure;
import org.qi4j.api.service.ImportedServiceDescriptor;
import org.qi4j.api.service.ServiceFinder;
import org.qi4j.api.service.ServiceImporter;
import org.qi4j.api.service.ServiceImporterException;
import org.qi4j.api.service.ServiceReference;
/**
* Use a registered service that implements ServiceImporter to do the actual
* import. The service id of the service that this importer should delegate to must
* be set as meta-info on this service. Example:
* <pre><code>
* module.services(MyServiceImporterService.class).identifiedBy("someid");
* module.importedServices(OtherService.class).importedBy(ServiceInstanceImporter.class).setMetaInfo("someid");
* </code></pre>
*/
public class ServiceInstanceImporter<T>
implements ServiceImporter<T>
{
@Structure
ServiceFinder finder;
ServiceImporter<T> service;
String serviceId;
@Override
public T importService( ImportedServiceDescriptor importedServiceDescriptor )
throws ServiceImporterException
{
serviceId = importedServiceDescriptor.metaInfo( String.class );
return serviceImporter().importService( importedServiceDescriptor );
}
@Override
public boolean isAvailable( T instance )
{
return serviceImporter().isAvailable( instance );
}
@SuppressWarnings( {"raw", "unchecked"} )
private ServiceImporter<T> serviceImporter()
{
if( service == null )
{
for( ServiceReference<ServiceImporter> reference : finder.<ServiceImporter>findServices( ServiceImporter.class ) )
{
if( reference.identity().equals( serviceId ) )
{
service = reference.get();
break;
}
}
}
if( service == null )
{
throw new ServiceImporterException( "No service importer with id '" + serviceId + "' was found" );
}
return service;
}
}