/*
 * 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.webui.gws;

import ru.codeinside.gses.webui.osgi.TRefRegistryImpl;

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

@Singleton
@Startup
public class TRefProvider {

  @Inject
  ServiceRefRegistry serviceRegistry;


  transient static ServiceRefRegistry instance;

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

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

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