edu.byu.hbll.box.DatabaseCopier Maven / Gradle / Ivy

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package edu.byu.hbll.box;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import edu.byu.hbll.box.internal.core.DefaultObjectFactory;
import edu.byu.hbll.json.YamlLoader;
import java.io.IOException;
import java.nio.file.Paths;

/**
 * Copies one box database to another. This includes a main method which requires a single yaml file
 * with the following format.
 *
 *  * sources:
 *   - from: src1
 *   - from: src2a
 *     to: src2b
 * db:
 *   from:
 *     type: # source database type
 *     params: # source database parameters
 *   to:
 *     type: # destination database type
 *     params: # destination database parameters
 * 
 */
public class DatabaseCopier {

  /**
   * Run the copier from the command line.
   *
   * @param args command-line arguments
   * @throws JsonProcessingException if an error occurs parsing the yaml file
   * @throws IOException if an error occurs parsing the yaml file
   */
  public static void main(String[] args) throws JsonProcessingException, IOException {
    if (args.length != 1) {
      System.err.println("the copier requires exactly one argument, path to the yaml");
      return;
    }

    JsonNode config = new YamlLoader().load(Paths.get(args[0]));

    for (JsonNode source : config.path("sources")) {
      String from;
      String to;

      if (source.isObject()) {
        from = source.path("from").asText();
        to = source.path("to").asText(from);
      } else {
        from = source.asText();
        to = from;
      }

      ObjectFactory objectFactory = new DefaultObjectFactory();
      JsonNode databaseConfig = config.path("db");
      BoxDatabase fromdb = BoxDatabase.create(from, objectFactory, databaseConfig.path("from"));
      BoxDatabase todb = BoxDatabase.create(to, objectFactory, databaseConfig.path("to"));

      copy(fromdb, todb);
    }
  }

  /**
   * Copies one database to another. Note that this only copies documents. The process queue and
   * groups are not copied.
   *
   * @param from the source database
   * @param to the destinations database
   */
  public static void copy(BoxDatabase from, BoxDatabase to) {
    long cursor = 0;

    while (true) {
      QueryResult result = from.find(new BoxQuery().setCursor(cursor).addAllStatuses());

      if (result.isEmpty()) {
        break;
      }

      to.save(result);
      cursor = result.getNextCursor();
    }
  }
}