I wrote an XML input transformer to ingest data from test directory and essentially store anything into a DB table. I attempted to make this as generic as possible.
I'm new to Java and also realize this approach is overly complicated, but really interested to here/read suggestions on my code.
Things I Dislike:
- I have to keep a reference to each associated repository in a map, then retrieve when saving items using the associated repository.
- I want the Map housing the repositories and associated variable names to exist in an external file, but can't make the repositories static, so makes it a bit difficult.
- The forEach in my stream is a bit ugly
Data Loader
import static java.lang.Class.*; import com.habicus.core.data.GoalRepository; import com.habicus.core.data.UserRepository; import com.habicus.repository.DataContainers.Container; import java.io.IOException; import java.util.Arrays; import java.util.Collection; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.logging.Level; import java.util.logging.Logger; import java.util.stream.Collectors; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import javax.xml.bind.Unmarshaller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.context.event.ApplicationReadyEvent; import org.springframework.context.ApplicationListener; import org.springframework.core.io.Resource; import org.springframework.core.io.support.*; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.stereotype.Component; /** * Launches at application boot-time to inject any user-defined test data and stores into test * database automatically */ @Component public class Loader implements ApplicationListener<ApplicationReadyEvent> { private static final Logger LOGGER = Logger.getLogger(Loader.class.getName()); Map<String, JpaRepository> reposByName = new HashMap<>(); @Autowired private UserRepository userRepo; @Autowired private GoalRepository goalRepo; /** * Strips off any dangling file extensions to enable class cast into file ingestor * * @param fileName * @return */ private static String normalizeFileName(String fileName) { return fileName.split(".xml")[0]; } /** * Takes input file from disk and parsed out contents by marshaling XML -> POJO * * @param inputFile * @param classReference * @return * @throws JAXBException */ private Container parseFile(Resource inputFile, Class<?> classReference) { try { JAXBContext jaxbContext = JAXBContext.newInstance(classReference); Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller(); return (Container) jaxbUnmarshaller.unmarshal(inputFile.getFile()); } catch (IOException | JAXBException exception) { LOGGER.log(Level.SEVERE, "Unable to unmarshal data!"); exception.printStackTrace(); } return null; } /** * Read in file from static resources directory * * @param fileResource * @return * @throws IOException * @throws JAXBException * @throws ClassNotFoundException */ private Container ingestFromFile(Resource fileResource) { if (fileResource == null) { throw new NullPointerException("File Resource Is Invalid"); } try { return parseFile( fileResource, forName( "com.habicus.repository.DataContainers." + normalizeFileName(fileResource.getFilename()))); } catch (ClassNotFoundException e) { e.printStackTrace(); } return null; } @Override public void onApplicationEvent(ApplicationReadyEvent event) { LOGGER.log(Level.INFO, "Preparing to load data into database"); /** BEGIN REPOSITORY MAP HERE */ reposByName.put("User", userRepo); reposByName.put("Goal", goalRepo); try { loadTestContainers(); } catch (IOException | JAXBException e) { LOGGER.log(Level.INFO, "Unable to store user data"); e.printStackTrace(); } } /** * Loads up any test data from resources and stores into embedded DB for test env * * @throws IOException * @throws JAXBException */ private void loadTestContainers() throws IOException, JAXBException { LOGGER.log(Level.INFO, "User data table being added to database"); Resource[] resources = retrieveTestDataFiles(); List<? extends Container> containers = Arrays.stream(resources).map(this::ingestFromFile).collect(Collectors.toList()); containers .stream() .map(Container.class::cast) .map(Container::getAll) .flatMap(Collection::stream) .collect(Collectors.toList()) .forEach( dataType -> { reposByName.get(dataType.toString()).save(dataType); LOGGER.log(Level.INFO, "Saved: " + dataType); }); } /** * Pulls out all test container files from static resources dir * * @return * @throws IOException */ private Resource[] retrieveTestDataFiles() throws IOException { ClassLoader cl = this.getClass().getClassLoader(); ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(cl); return resolver.getResources("classpath*:/testDatabase/*Container.xml"); } } 
