PayloadWriter.java

package gov.loc.repository.bagit.writer;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.util.ResourceBundle;
import java.util.Set;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import gov.loc.repository.bagit.domain.Bag;
import gov.loc.repository.bagit.domain.Manifest;
import gov.loc.repository.bagit.domain.Version;

/**
 * Responsible for writing out the bag payload to the filesystem
 */
public final class PayloadWriter {
  private static final Logger logger = LoggerFactory.getLogger(PayloadWriter.class);
  private static final Version VERSION_2_0 = new Version(2, 0);
  private static final ResourceBundle messages = ResourceBundle.getBundle("MessageBundle");
  
  private PayloadWriter(){
    //intentionally left empty
  }
  
  /*
   * Write the payload files in the data directory or under the root directory depending on the version
   */
  static Path writeVersionDependentPayloadFiles(final Bag bag, final Path outputDir) throws IOException{
    Path bagitDir = outputDir;
    //@Incubating
    if(bag.getVersion().isSameOrNewer(VERSION_2_0)){
      bagitDir = outputDir.resolve(".bagit");
      Files.createDirectories(bagitDir);
      writePayloadFiles(bag.getPayLoadManifests(), outputDir, bag.getRootDir());
    }
    else{
      final Path dataDir = outputDir.resolve("data");
      Files.createDirectories(dataDir);
      writePayloadFiles(bag.getPayLoadManifests(), dataDir, bag.getRootDir().resolve("data"));
    }
    
    return bagitDir;
  }
  
  /**
  * Write the payload <b>file(s)</b> to the output directory
  * 
  * @param payloadManifests the set of objects representing the payload manifests
  * @param outputDir the data directory of the bag
  * @param bagDataDir the data directory of the bag
  * 
  * @throws IOException if there was a problem writing a file
  */
 public static void writePayloadFiles(final Set<Manifest> payloadManifests, final Path outputDir, final Path bagDataDir) throws IOException{
   logger.info(messages.getString("writing_payload_files"));
   for(final Manifest payloadManifest : payloadManifests){
     for(final Path payloadFile : payloadManifest.getFileToChecksumMap().keySet()){
       final Path relativePayloadPath = bagDataDir.relativize(payloadFile); 
           
       final Path writeToPath = outputDir.resolve(relativePayloadPath);
       logger.debug(messages.getString("writing_payload_file_to_path"), payloadFile, writeToPath);
       final Path parent = writeToPath.getParent();
       if(parent != null){
         Files.createDirectories(parent);
       }
       Files.copy(payloadFile, writeToPath, StandardCopyOption.COPY_ATTRIBUTES, StandardCopyOption.REPLACE_EXISTING);
     }
   }
 }
}