dnet-hadoop/dhp-wf/dhp-wf-import/src/main/java/eu/dnetlib/dhp/wf/importer/facade/ServiceFacadeUtils.java

81 lines
3.1 KiB
Java

package eu.dnetlib.dhp.wf.importer.facade;
import static eu.dnetlib.dhp.wf.importer.ImportWorkflowRuntimeParameters.IMPORT_FACADE_FACTORY_CLASS;
import java.lang.reflect.Constructor;
import java.util.Map;
import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.conf.Configuration;
import com.google.common.collect.ImmutableMap;
import eu.dnetlib.dhp.wf.importer.ImportWorkflowRuntimeParameters;
/**
* Service facade utility methods.
* @author mhorst
*
*/
public final class ServiceFacadeUtils {
//------------------------ CONSTRUCTORS -------------------
private ServiceFacadeUtils() {}
//------------------------ LOGIC --------------------------
/**
* Instantiates service based on provided parameters.
*
* Service factory class name is mandatory and has to be provided as {@value ImportWorkflowRuntimeParameters#IMPORT_FACADE_FACTORY_CLASS} parameter.
* Other parameters will be used by factory itself. Factory must be instantiable with no-argument construtor.
*
* @param parameters set of parameters required for service instantiation
*
*/
public static <T> T instantiate(Map<String, String> parameters) throws ServiceFacadeException {
String serviceFactoryClassName = parameters.get(IMPORT_FACADE_FACTORY_CLASS);
if (StringUtils.isBlank(serviceFactoryClassName)) {
throw new ServiceFacadeException("unknown service facade factory, no " + IMPORT_FACADE_FACTORY_CLASS + " parameter provided!");
}
try {
Class<?> clazz = Class.forName(serviceFactoryClassName);
Constructor<?> constructor = clazz.getConstructor();
@SuppressWarnings("unchecked")
ServiceFacadeFactory<T> serviceFactory = (ServiceFacadeFactory<T>) constructor.newInstance();
return serviceFactory.instantiate(parameters);
} catch (Exception e) {
throw new ServiceFacadeException("exception occurred while instantiating service by facade factory: " + IMPORT_FACADE_FACTORY_CLASS, e);
}
}
/**
* Instantiates service based on provided configuration.
*
* Service factory class name is mandatory and has to be provided as {@value ImportWorkflowRuntimeParameters#IMPORT_FACADE_FACTORY_CLASS} configuration entry.
* Other parameters will be used by factory itself. Factory must be instantiable with no-argument construtor.
*
* @param config set of configuration entries required for service instantiation
*/
public static <T> T instantiate(Configuration config) throws ServiceFacadeException {
return instantiate(buildParameters(config));
}
// ------------------------ PRIVATE --------------------------
/**
* Converts configuration entries into plain map.
*/
private static Map<String, String> buildParameters(Configuration config) {
ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
for (Map.Entry<String, String> entry : config) {
builder.put(entry);
}
return builder.build();
}
}