content: package act.db;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 ActFramework
   * %%
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   * #L%
   */
  
  import act.util.SimpleBean;
  
  public interface Model<ID_TYPE, MODEL_TYPE extends Model> extends SimpleBean {
      /**
       * Returns the ID (key) of this entity
       *
       * @return the id
       */
      ID_TYPE _id();
  
      /**
       * Set the ID(key) to this entity. This method assume the
       * entity is at <b>empty</b> state, i.e. there is no ID already
       * assigned to this entity before calling this method. Otherwise
       * the {@link IllegalStateException} will be thrown out
       * @param id the ID to be set to this entity
       * @return this entity itself
       * @throws IllegalStateException if ID has already set on this entity
       */
      MODEL_TYPE _id(ID_TYPE id);
  
      /**
       * Returns {@code true} if the entity is just created in memory or been
       * loaded from data storage
       */
      boolean _isNew();
  }
  