/*
    * @(#)$Id: StorageManager.java 777 2010-03-11 19:45:18Z bpuype $
    *
    * Author       :   Ueli Kurmann, igesture@uelikurmann.ch
    *
    * Purpose      : 	The front-end of the storage system. The storage
    *                  manager uses a storage engine which provides
    *                  functionality to access different data sources. 
    *
   * -----------------------------------------------------------------------
   *
   * Revision Information:
   *
   * Date             Who         Reason
   *
   * Dec 26, 2006     ukurmann    Initial Release
   * Mar 22, 2007     bsigner     Cleanup
   *
   * -----------------------------------------------------------------------
   *
   * Copyright 1999-2009 ETH Zurich. All Rights Reserved.
   *
   * This software is the proprietary information of ETH Zurich.
   * Use is subject to license terms.
   * 
   */
  
  package org.ximtec.igesture.storage;
  
  import java.io.File;
  import java.util.List;
  import java.util.logging.Logger;
  
  import org.sigtec.util.Constant;
  import org.ximtec.igesture.core.DataObject;
  
  /**
   * The front-end of the storage system. The storage manager uses a storage
   * engine which provides functionality to access different data sources.
   * 
   * @version 1.0, Dec 2006
   * @author Ueli Kurmann, igesture@uelikurmann.ch
   * @author Beat Signer, signer@inf.ethz.ch
   */
  public class StorageManager implements IStorageManager {
  
    private static final Logger LOGGER = Logger.getLogger(StorageManager.class.getName());
  
    private static final String LOADING_DB = "Loading database from '";
  
    private StorageEngine storageEngine;
    
    
  
    public enum StorageEngineType {
      igd, igdc, igx, igz
    }
  
    /**
     * Instantiates the storage manager with the given storage engine.
     * 
     * @param engine
     *          the storage engine to be used.
     */
    public StorageManager(StorageEngine engine) {
      this.storageEngine = engine;
    }
  
    /**
     * Loads the data object of the given type with the given id.
     * 
     * @param clazz
     *          the type of the data object to be retrieved.
     * @param id
     *          the id of the data object.
     * @return the data object with the given id.
     */
    @Override
    public <T extends DataObject> T load(Class<T> clazz, String id) {
      return storageEngine.load(clazz, id);
    } // load
  
    /**
     * Returns a typed list of data objects. All objects available in the
     * collection with the given type are returned.
     * 
     * @param clazz
     *          the type of the data objects.
     * @return a list of data objects of the given type.
     */
    @Override
    public <T extends DataObject> List<T> load(Class<T> clazz) {
      return storageEngine.load(clazz);
    } // load
  
    /**
     * Removes the given data object from the storage.
     */
    @Override
   public void remove(DataObject dataObject) {
     storageEngine.remove(dataObject);
   } // remove
 
   /**
    * Stores a data object.
    * 
    * @param object
    *          the data object to be stored.
    */
   @Override
   public void store(DataObject dataObject) {
     storageEngine.store(dataObject);
   } // store
 
   /**
    * Stores a list of data objects.
    * 
    * @param dataObjects
    *          the data objects to be stored.
    */
   @Override
   public void store(List<DataObject> dataObjects) {
     for (final DataObject dataObject : dataObjects) {
       store(dataObject);
     }
 
   } // store
 
   /**
    * Updates a data object.
    * 
    * @param dataObject
    *          the data object to be updated.
    */
   @Override
   public void update(DataObject dataObject) {
     storageEngine.update(dataObject);
   } // update
 
   /**
    * Updates a list of data objects.
    * 
    * @param dataObjects
    *          the list of data objects to be updated.
    */
   @Override
   public void update(List<DataObject> dataObjects) {
     for (final DataObject obj : dataObjects) {
       update(obj);
     }
 
   } // update
 
   /**
    * Generates a UUID. This id is used to identify data objects.
    * 
    * @return an new UUID
    */
   public static String generateUUID() {
     return org.safehaus.uuid.UUIDGenerator.getInstance().generateRandomBasedUUID().toString();
   } // generateUUID
 
   /**
    * Creates a new storage engine. The type of the storage engine is determined
    * based on the file extension. Dynamic class loading should be used to avoid
    * any license conflicts.
    * 
    * @param file
    *          the file from which the storage engine is created.
    * @return the new storage engine.
    */
   public static StorageEngine createStorageEngine(File file) {
     LOGGER.info(LOADING_DB + file + Constant.SINGLE_QUOTE);
     StorageEngine engine = null;
 
     switch (getEngineType(file)) {
     case igd:
     case igdc:
       engine = new Db4oStorageEngine(file.getPath());
       break;
     case igx:
       engine = new XMLStorageEngine(file.getPath());
       break;
     case igz:
       engine = new ZipStorageEngine(file.getPath());
       break;
     default:
     }
 
     return engine;
   } // createStorageEngine
 
   public static StorageEngineType getEngineType(File file) {
     String extension = file.getName().substring(file.getName().lastIndexOf(Constant.DOT) + 1);
     return StorageEngineType.valueOf(extension);
   } // getFileType
 
   /**
    * Disposes the storage engine.
    */
   @Override
   public void dispose() {
     if (storageEngine != null) {
       storageEngine.dispose();
     }
   } // dispose
 
   @Override
   public <T extends DataObject> List<T> load(Class<T> clazz, String fieldName, Object value) {
     return storageEngine.load(clazz, fieldName, value);
   } // load
 
   @Override
   public void commit() {
     if (storageEngine != null) {
       storageEngine.commit();
     }
   } // commit
   
   /*
    * (non-Javadoc)
    * @see org.ximtec.igesture.storage.StorageEngine#copyTo(java.io.File)
    */
   @Override
   public void copyTo(File file) {
     storageEngine.copyTo(file);
     
   }
 
 }