content: /*
   * Copyright (C) 2017 The Android Open Source Project
   *
   * 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.example.android.observability.persistence;
  
  import androidx.room.Database;
  import androidx.room.Room;
  import androidx.room.RoomDatabase;
  import android.content.Context;
  
  /**
   * The Room database that contains the Users table
   */
  @Database(entities = {User.class}, version = 1)
  public abstract class UsersDatabase extends RoomDatabase {
  
      private static volatile UsersDatabase INSTANCE;
  
      public abstract UserDao userDao();
  
      public static UsersDatabase getInstance(Context context) {
          if (INSTANCE == null) {
              synchronized (UsersDatabase.class) {
                  if (INSTANCE == null) {
                      INSTANCE = Room.databaseBuilder(context.getApplicationContext(),
                              UsersDatabase.class, "Sample.db")
                              .build();
                  }
              }
          }
          return INSTANCE;
      }
  
  }
  