/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 * Copyright (c) 2013, MPL CodeInside http://codeinside.ru
 */

package ru.codeinside.gses.service;

import ru.codeinside.gses.service.impl.DeclarantServiceImpl;
import ru.codeinside.gws.api.ServerException;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.ejb.Lock;
import javax.ejb.LockType;
import javax.ejb.Singleton;
import javax.ejb.Startup;
import javax.inject.Inject;

@Singleton
@Startup
@Lock(LockType.READ)
public class DeclarantServiceProvider {

  @Inject
  DeclarantService declarantService;

  transient static DeclarantService instance;

  @PostConstruct
  void initialize() {
    synchronized (DeclarantServiceImpl.class) {
      if (instance == null) {
        instance = declarantService;
      }
    }
  }

  @PreDestroy
  void shutdown() {
    synchronized (DeclarantServiceImpl.class) {
      if (instance == declarantService) {
        instance = null;
      }
    }
  }

  public static DeclarantService get() {
    DeclarantService result = instance;
    if (result == null) {
      throw new IllegalStateException("Сервис не зарегистрирован!");
    }
    return result;
  }

  public static DeclarantService forApi() {
    DeclarantService result = instance;
    if (result == null) {
      throw new ServerException("Хранилище заявок не доступно");
    }
    return result;
  }

}