package xuml.tools.datastore.gae;
   
   import xuml.tools.datastore.DatastoreText;
   
   import com.google.appengine.api.datastore.DatastoreService;
   import com.google.appengine.api.datastore.DatastoreServiceFactory;
   import com.google.appengine.api.datastore.Entity;
   import com.google.appengine.api.datastore.EntityNotFoundException;
   import com.google.appengine.api.datastore.Key;
  import com.google.appengine.api.datastore.KeyFactory;
  import com.google.appengine.api.datastore.Text;
  
  /**
   * Implements storage of string properties in Google App Engine's Big Table
   * datastore.
   * 
   * @author dave
   * 
   */
  public class DatastoreTextGae implements DatastoreText {
  
      private static DatastoreText datastore = new DatastoreTextGae();
  
      public static DatastoreText instance() {
          return datastore;
      }
  
      @Override
      public void put(String kind, String name, String property, String value) {
          DatastoreService ds = DatastoreServiceFactory.getDatastoreService();
          Key k = KeyFactory.createKey(kind, name);
          System.out.println("putting " + k + "=" + value);
          Entity ent = new Entity(k);
          ent.setProperty(property, new Text(value));
          ds.put(ent);
      }
  
      @Override
      public String get(String kind, String name, String property) {
          System.out.println("getting");
          DatastoreService ds = DatastoreServiceFactory.getDatastoreService();
          Key k = KeyFactory.createKey(kind, name);
          String result;
          try {
              Entity ent = ds.get(k);
              System.out.println(ent.getProperties());
              Text prop = (Text) ent.getProperty(property);
              System.out.println("Datastore.get " + k + "= " + prop);
              if (prop != null)
                  result = prop.getValue();
              else
                  result = null;
          } catch (EntityNotFoundException e) {
              System.out.println(e.getMessage());
              result = null;
          }
          System.out.println("get returns " + result);
          return result;
      }
  
  }