PersistenceService.java

/**
 * Copyright (C) 2012 Stephan Classen
 * Based on guice-perist (Copyright (C) 2010 Google, Inc.)
 *
 * 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.
 */
package com.github.sclassen.guicejpa;

/**
 * This is the main control to the entire persistence engine. Before calling any other method
 * of either {@link UnitOfWork}, {@link EntityManagerProvider}, or any method annotated with
 * @{@link Transactional} the persistence service must be started.
 *
 * @author Stephan Classen
 */
public interface PersistenceService {

  /**
   * Starts the underlying persistence engine and makes jpa-persist ready for use.
   * This method must be called by your code prior to using any other jpa-persist artifacts.
   * If you are using jpa-persist in a web container {@link PersistenceFilter} will call this
   * method upon initialization of the web application.
   *
   * @throws IllegalArgumentException if the service is already running.
   */
  void start() throws IllegalArgumentException;

  /**
   * @return {@code true} if the underlying persistence engine is running.
   *         {@code false} otherwise.
   **/
  boolean isRunning();

  /**
   * Stops the underlying persistence engine.
   * <ul>
   *  <li>If already stopped, calling this method does nothing.</li>
   *  <li>If not yet started, it also does nothing.</li>
   * </ul>
   */
  void stop();

}