public class BusinessLogicClass {
  public void DoSomething()  {
    // Go get some configuration
    int threshold = 
      int.Parse(ConfigurationManager.AppSettings["threshold"]);

    string connectionString = 
      ConfigurationManager.AppSettings["connectionString"];

    string sql = 
      @"select * from things 
        size > ";

    sql += threshold;

    using (sqlConnection connection = 
      new sqlConnection(connectionString)) {

      connection.Open();

      sqlCommand command = new sqlCommand(sql,connection);
      using (sqlDataReader reader = command.ExecuteReader()) {
        while (reader.Read()) {
          string name = reader["Name"].ToString();
          string destination = reader["destination"].ToString();

          // do some business logic in here
          doSomeBusinessLogic(name,destination,connection);
        }  
      }
    }
  }
}

public void Process() {
  string connectionString = getConnectionString();
  sqlConnection connection = new sqlConnection(connectionString);
  DataServer1 server = new DataServer1(connection);

  int daysOld = 5;
  using (sqlDataReader reader = server.GetWorkItemData(daysOld)) {
    while (reader.Read()) {
      string name = reader.GetString(0);
      string location = reader.GetString(1);

      processItem(name,location); 
    }
  }
}

public interface DataService {
  InsuranceClaim[] FindClaims(Customer customer);
}

public class Repository {
  public DataService InnerService { get; set; }
}

public class ClassThatNeedsInsuranceClaim {
  private Repository _repository;

  public ClassThatNeedsInsuranceClaim(Repository repository) {
    _repository = repository;
  }

  public void TallyAllTheOutstandingClaims(Customer customer) {
    // This line of code violates the Law of Demeter
    InsuranceClaim[] claims = 
      _repository.InnerService.FindClaims(customer);
  }
}

public class Repository2 {
  private DataService _service;

  public Repository2(DataService service) {
    _service = service;
  }

  public InsuranceClaim[] FindClaims(Customer customer) {
    // we're simply going to delegate to the inner
    // DataService for now,but who knows what 
    // we want to do in the future?
    return _service.FindClaims(customer);
  }
}

public class ClassThatNeedsInsuranceClaim2 {
  private Repository2 _repository;

  public ClassThatNeedsInsuranceClaim2(
    Repository2 repository) {
    _repository = repository;
  }

  public void TallyAllTheOutstandingClaims(
    Customer customer) {
    // This line of code now follows the Law of Demeter
    InsuranceClaim[] claims = _repository.FindClaims(customer);
  }
}

public class DumbPurchase {
  public double SubTotal { get; set; }
  public double Discount { get; set; }
  public double Total { get; set; }
}

public class DumbAccount {
  public double Balance { get; set;}
}

public class ClassThatUsesDumbEntities {
  public void MakePurchase(
    DumbPurchase purchase,DumbAccount account) {
    purchase.Discount = purchase.SubTotal > 10000 ? .10 : 0;
    purchase.Total = 
      purchase.SubTotal*(1 - purchase.Discount);

    if (purchase.Total < account.Balance) {
      account.Balance -= purchase.Total;
    }
    else {
      rejectPurchase(purchase,"You don't have enough money.");
    }
  }
} 

public class Purchase {
  private readonly double _subTotal;

  public Purchase(double subTotal) {
    _subTotal = subTotal;
  }

  public double Total {
    get {
      double discount = _subTotal > 10000 ? .10 : 0;
      return _subTotal*(1 - discount);
    }
  }
}

public class Account {
  private double _balance;

  public void Deduct(
    Purchase purchase,PurchaseMessenger messenger) {
    if (purchase.Total < _balance) {
      _balance -= purchase.Total;
    }
    else {
      messenger.RejectPurchase(purchase,this);
    }
  }
}

public class ClassThatObeysTellDontAsk {
  public void MakePurchase(
    Purchase purchase,Account account) {
    PurchaseMessenger messenger = new PurchaseMessenger();
    account.Deduct(purchase,messenger);
  }
}