package de.mpg.mpiwg.berlin.mpdl.externalObjects.db;

import java.io.File;

import com.sleepycat.je.Database;
import com.sleepycat.je.DatabaseConfig;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.je.Environment;
import com.sleepycat.je.EnvironmentConfig;

import de.mpg.mpiwg.berlin.mpdl.exception.ApplicationException;

public class DbEnvExternalObjects {
  private String dataDir;
  private File envPath;
  private Environment env;
  private EnvironmentConfig envConfig;
  private DatabaseConfig dbConfig;
  private Database elementDB;
  private Database objectDB;

  public DbEnvExternalObjects() {
  }

  public void setDataDir(String dataDir) {
    this.dataDir = dataDir;
  }
  
  public void init() throws ApplicationException {
    try {
      envConfig = new EnvironmentConfig();
      dbConfig = new DatabaseConfig();
      envConfig.setReadOnly(false);
      dbConfig.setReadOnly(false);
      envConfig.setAllowCreate(true);
      dbConfig.setAllowCreate(true);
      envConfig.setTransactional(true);
      dbConfig.setTransactional(true);
      // allow duplicates for keys
      dbConfig.setSortedDuplicates(true);
      envPath = new File(dataDir);
      env = new Environment(envPath, envConfig);
    } catch (DatabaseException e) {
      throw new ApplicationException(e);
    }
  }

  public void openDatabases() throws ApplicationException {
    try {
      // open databases (and create them if they do not exist)
      elementDB = env.openDatabase(null, "ElementDB", dbConfig);
      objectDB = env.openDatabase(null, "ObjectDB", dbConfig);
    } catch (DatabaseException e) {
      throw new ApplicationException(e);
    }
  }
  
  public void removeDatabases() throws ApplicationException {
    try {
      if (objectDB != null)
        objectDB.close();
      if (elementDB != null)
        elementDB.close();
      env.removeDatabase(null, "ElementDB");    
      env.removeDatabase(null, "ObjectDB");
      objectDB = null;
      elementDB = null;
      /*   
      env.truncateDatabase(null, "ElementDB", bla);    
      env.truncateDatabase(null, "ObjectDB", bla);
      */
    } catch (DatabaseException e) {
      throw new ApplicationException(e);
    }
  }
  
  public Environment getEnv() {
    return env;
  }

  public Database getElementDB() {
    return elementDB;
  }

  public Database getObjectDB() {
    return objectDB;
  }

  public void close() throws ApplicationException {
    if (env != null) {
      try {
        if (objectDB != null)
          objectDB.close();
        if (elementDB != null)
          elementDB.close();
        if (env != null)
          env.close();
      } catch (DatabaseException e) {
        throw new ApplicationException(e);
      }
    }
  }
}