?? userdatabasefactory.cs
字號:
using System;
using System.Collections.Generic;
using System.Text;
namespace Project1
{
public class UserDatabaseFactory
{
private static UserDatabase DB_INSTANCE = createInstance();
/// <summary>
/// Create an instance of the UserDatabase
/// </summary>
/// <returns>An instance of the UserDatabase</returns>
private static UserDatabase createInstance()
{
try
{
UserDatabase userDatabase = new UserDatabaseImp();
return userDatabase;
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
return null;
}
}
/// <summary>
/// Get an instance of user database
/// </summary>
/// <returns>an instance of UserDatabase</returns>
public static UserDatabase getDatabaseInstance()
{
return DB_INSTANCE;
}
/// <summary>
/// Make sure this class cannot be initialized
/// </summary>
private UserDatabaseFactory()
{
// do nothing
}
}
}
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