I have been reading Working Effectively with Legacy Code and Clean Code with the goal of learning strategies on how to begin cleaning up the existing code-base of a large ASP.NET webforms application.

This system has been around since 2005 and since then has undergone a number of enhancements. Originally the code was structured as follows (and is still largely structured this way):

• ASP.NET (aspx/ascx)
• Code-behind (c#)
• Business Logic Layer (c#)
• Data Access Layer (c#)
• Database (Oracle)

The main issue is that the code is procedural masquerading as object-oriented. It virtually violates all of the guidelines described in both books.

This is an example of a typical class in the Business Logic Layer:

    public class AddressBO
{
    public TransferObject GetAddress(string addressID)
    {
        if (StringUtils.IsNull(addressID))
        {
            throw new ValidationException("Address ID must be entered");
        }

        AddressDAO addressDAO = new AddressDAO();
        return addressDAO.GetAddress(addressID);
    }

    public TransferObject Insert(TransferObject addressDetails)
    {
        if (StringUtils.IsNull(addressDetails.GetString("EVENT_ID")) ||
            StringUtils.IsNull(addressDetails.GetString("LOCALITY")) ||
            StringUtils.IsNull(addressDetails.GetString("ADDRESS_TARGET")) ||
            StringUtils.IsNull(addressDetails.GetString("ADDRESS_TYPE_CODE")) ||
            StringUtils.IsNull(addressDetails.GetString("CREATED_BY")))
        {
            throw new ValidationException(
                "You must enter an Event ID, Locality, Address Target, Address Type Code and Created By.");
        }

        string addressID = Sequence.GetNextValue("ADDRESS_ID_SEQ");
        addressDetails.SetValue("ADDRESS_ID", addressID);

        string syncID = Sequence.GetNextValue("SYNC_ID_SEQ");
        addressDetails.SetValue("SYNC_ADDRESS_ID", syncID);

        TransferObject syncDetails = new TransferObject();

        Transaction transaction = new Transaction();

        try
        {
            AddressDAO addressDAO = new AddressDAO();
            addressDAO.Insert(addressDetails, transaction);

            // insert the record for the target
            TransferObject addressTargetDetails = new TransferObject();
            switch (addressDetails.GetString("ADDRESS_TARGET"))
            {
                case "PARTY_ADDRESSES":
                    {
                        addressTargetDetails.SetValue("ADDRESS_ID", addressID);
                        addressTargetDetails.SetValue("ADDRESS_TYPE_CODE",
                                                      addressDetails.GetString("ADDRESS_TYPE_CODE"));
                        addressTargetDetails.SetValue("PARTY_ID", addressDetails.GetString("PARTY_ID"));
                        addressTargetDetails.SetValue("EVENT_ID", addressDetails.GetString("EVENT_ID"));
                        addressTargetDetails.SetValue("CREATED_BY", addressDetails.GetString("CREATED_BY"));

                        addressDAO.InsertPartyAddress(addressTargetDetails, transaction);

                        break;
                    }
                case "PARTY_CONTACT_ADDRESSES":
                    {
                        addressTargetDetails.SetValue("ADDRESS_ID", addressID);
                        addressTargetDetails.SetValue("ADDRESS_TYPE_CODE",
                                                      addressDetails.GetString("ADDRESS_TYPE_CODE"));
                        addressTargetDetails.SetValue("PUBLIC_RELEASE_FLAG",
                                                      addressDetails.GetString("PUBLIC_RELEASE_FLAG"));
                        addressTargetDetails.SetValue("CONTACT_ID", addressDetails.GetString("CONTACT_ID"));
                        addressTargetDetails.SetValue("EVENT_ID", addressDetails.GetString("EVENT_ID"));
                        addressTargetDetails.SetValue("CREATED_BY", addressDetails.GetString("CREATED_BY"));

                        addressDAO.InsertContactAddress(addressTargetDetails, transaction);

                        break;
                    }

                << many more cases here >>
                default:
                    {
                        break;
                    }
            }

            // synchronise
            SynchronisationBO synchronisationBO = new SynchronisationBO();
            syncDetails = synchronisationBO.Synchronise("I", transaction,
                                                        "ADDRESSES", addressDetails.GetString("ADDRESS_TARGET"),
                                                        addressDetails, addressTargetDetails);


            // commit
            transaction.Commit();
        }
        catch (Exception)
        {
            transaction.Rollback();
            throw;
        }

        return new TransferObject("ADDRESS_ID", addressID, "SYNC_DETAILS", syncDetails);
    }


    << many more methods are here >>

}

It has a lot of duplication, the class has a number of responsibilities, etc, etc - it is just generally 'un-clean' code.

All of the code throughout the system is dependent on concrete implementations.

This is an example of a typical class in the Data Access Layer:

    public class AddressDAO : GenericDAO
{
    public static readonly string BASE_SQL_ADDRESSES =
        "SELECT " +
        "  a.address_id, " +
        "  a.event_id, " +
        "  a.flat_unit_type_code, " +
        "  fut.description as flat_unit_description, " +
        "  a.flat_unit_num, " +
        "  a.floor_level_code, " +
        "  fl.description as floor_level_description, " +
        "  a.floor_level_num, " +
        "  a.building_name, " +
        "  a.lot_number, " +
        "  a.street_number, " +
        "  a.street_name, " +
        "  a.street_type_code, " +
        "  st.description as street_type_description, " +
        "  a.street_suffix_code, " +
        "  ss.description as street_suffix_description, " +
        "  a.postal_delivery_type_code, " +
        "  pdt.description as postal_delivery_description, " +
        "  a.postal_delivery_num, " +
        "  a.locality, " +
        "  a.state_code, " +
        "  s.description as state_description, " +
        "  a.postcode, " +
        "  a.country, " +
        "  a.lock_num, " +
        "  a.created_by, " +
        "  TO_CHAR(a.created_datetime, '" + SQL_DATETIME_FORMAT + "') as created_datetime, " +
        "  a.last_updated_by, " +
        "  TO_CHAR(a.last_updated_datetime, '" + SQL_DATETIME_FORMAT + "') as last_updated_datetime, " +
        "  a.sync_address_id, " +
        "  a.lat," +
        "  a.lon, " +
        "  a.validation_confidence, " +
        "  a.validation_quality, " +
        "  a.validation_status " +
        "FROM ADDRESSES a, FLAT_UNIT_TYPES fut, FLOOR_LEVELS fl, STREET_TYPES st, " +
        "     STREET_SUFFIXES ss, POSTAL_DELIVERY_TYPES pdt, STATES s " +
        "WHERE a.flat_unit_type_code = fut.flat_unit_type_code(+) " +
        "AND   a.floor_level_code = fl.floor_level_code(+) " +
        "AND   a.street_type_code = st.street_type_code(+) " +
        "AND   a.street_suffix_code = ss.street_suffix_code(+) " +
        "AND   a.postal_delivery_type_code = pdt.postal_delivery_type_code(+) " +
        "AND   a.state_code = s.state_code(+) ";


    public TransferObject GetAddress(string addressID)
    {
        //Build the SELECT Statement
        StringBuilder selectStatement = new StringBuilder(BASE_SQL_ADDRESSES);

        //Add WHERE condition
        selectStatement.Append(" AND a.address_id = :addressID");

        ArrayList parameters = new ArrayList{DBUtils.CreateOracleParameter("addressID", OracleDbType.Decimal, addressID)};

        // Execute the SELECT statement
        Query query = new Query();
        DataSet results = query.Execute(selectStatement.ToString(), parameters);

        // Check if 0 or more than one rows returned
        if (results.Tables[0].Rows.Count == 0)
        {
            throw new NoDataFoundException();
        }
        if (results.Tables[0].Rows.Count > 1)
        {
            throw new TooManyRowsException();
        }

        // Return a TransferObject containing the values
        return new TransferObject(results);
    }


    public void Insert(TransferObject insertValues, Transaction transaction)
    {
        // Store Values
        string addressID = insertValues.GetString("ADDRESS_ID");
        string syncAddressID = insertValues.GetString("SYNC_ADDRESS_ID");
        string eventID = insertValues.GetString("EVENT_ID");
        string createdBy = insertValues.GetString("CREATED_BY");

        // postal delivery
        string postalDeliveryTypeCode = insertValues.GetString("POSTAL_DELIVERY_TYPE_CODE");
        string postalDeliveryNum = insertValues.GetString("POSTAL_DELIVERY_NUM");

        // unit/building
        string flatUnitTypeCode = insertValues.GetString("FLAT_UNIT_TYPE_CODE");
        string flatUnitNum = insertValues.GetString("FLAT_UNIT_NUM");
        string floorLevelCode = insertValues.GetString("FLOOR_LEVEL_CODE");
        string floorLevelNum = insertValues.GetString("FLOOR_LEVEL_NUM");
        string buildingName = insertValues.GetString("BUILDING_NAME");

        // street
        string lotNumber = insertValues.GetString("LOT_NUMBER");
        string streetNumber = insertValues.GetString("STREET_NUMBER");
        string streetName = insertValues.GetString("STREET_NAME");
        string streetTypeCode = insertValues.GetString("STREET_TYPE_CODE");
        string streetSuffixCode = insertValues.GetString("STREET_SUFFIX_CODE");

        // locality/state/postcode/country
        string locality = insertValues.GetString("LOCALITY");
        string stateCode = insertValues.GetString("STATE_CODE");
        string postcode = insertValues.GetString("POSTCODE");
        string country = insertValues.GetString("COUNTRY");

        // esms address
        string esmsAddress = insertValues.GetString("ESMS_ADDRESS");

        //address/GPS
        string lat = insertValues.GetString("LAT");
        string lon = insertValues.GetString("LON");
        string zoom = insertValues.GetString("ZOOM");

        //string validateDate = insertValues.GetString("VALIDATED_DATE");
        string validatedBy = insertValues.GetString("VALIDATED_BY");
        string confidence = insertValues.GetString("VALIDATION_CONFIDENCE");
        string status = insertValues.GetString("VALIDATION_STATUS");
        string quality = insertValues.GetString("VALIDATION_QUALITY");


        // the insert statement
        StringBuilder insertStatement = new StringBuilder("INSERT INTO ADDRESSES (");
        StringBuilder valuesStatement = new StringBuilder("VALUES (");

        ArrayList parameters = new ArrayList();

        // build the insert statement
        insertStatement.Append("ADDRESS_ID, EVENT_ID, CREATED_BY, CREATED_DATETIME, LOCK_NUM ");
        valuesStatement.Append(":addressID, :eventID, :createdBy, SYSDATE, 1 ");
        parameters.Add(DBUtils.CreateOracleParameter("addressID", OracleDbType.Decimal, addressID));
        parameters.Add(DBUtils.CreateOracleParameter("eventID", OracleDbType.Decimal, eventID));
        parameters.Add(DBUtils.CreateOracleParameter("createdBy", OracleDbType.Varchar2, createdBy));

        // build the insert statement
        if (!StringUtils.IsNull(syncAddressID))
        {
            insertStatement.Append(", SYNC_ADDRESS_ID");
            valuesStatement.Append(", :syncAddressID");
            parameters.Add(DBUtils.CreateOracleParameter("syncAddressID", OracleDbType.Decimal, syncAddressID));
        }

        if (!StringUtils.IsNull(postalDeliveryTypeCode))
        {
            insertStatement.Append(", POSTAL_DELIVERY_TYPE_CODE");
            valuesStatement.Append(", :postalDeliveryTypeCode ");
            parameters.Add(DBUtils.CreateOracleParameter("postalDeliveryTypeCode", OracleDbType.Varchar2, postalDeliveryTypeCode));
        }

        if (!StringUtils.IsNull(postalDeliveryNum))
        {
            insertStatement.Append(", POSTAL_DELIVERY_NUM");
            valuesStatement.Append(", :postalDeliveryNum ");
            parameters.Add(DBUtils.CreateOracleParameter("postalDeliveryNum", OracleDbType.Varchar2, postalDeliveryNum));
        }

        if (!StringUtils.IsNull(flatUnitTypeCode))
        {
            insertStatement.Append(", FLAT_UNIT_TYPE_CODE");
            valuesStatement.Append(", :flatUnitTypeCode ");
            parameters.Add(DBUtils.CreateOracleParameter("flatUnitTypeCode", OracleDbType.Varchar2, flatUnitTypeCode));
        }

        if (!StringUtils.IsNull(lat))
        {
            insertStatement.Append(", LAT");
            valuesStatement.Append(", :lat ");
            parameters.Add(DBUtils.CreateOracleParameter("lat", OracleDbType.Decimal, lat));
        }

        if (!StringUtils.IsNull(lon))
        {
            insertStatement.Append(", LON");
            valuesStatement.Append(", :lon ");
            parameters.Add(DBUtils.CreateOracleParameter("lon", OracleDbType.Decimal, lon));
        }

        if (!StringUtils.IsNull(zoom))
        {
            insertStatement.Append(", ZOOM");
            valuesStatement.Append(", :zoom ");
            parameters.Add(DBUtils.CreateOracleParameter("zoom", OracleDbType.Decimal, zoom));
        }

        if (!StringUtils.IsNull(flatUnitNum))
        {
            insertStatement.Append(", FLAT_UNIT_NUM");
            valuesStatement.Append(", :flatUnitNum ");
            parameters.Add(DBUtils.CreateOracleParameter("flatUnitNum", OracleDbType.Varchar2, flatUnitNum));
        }

        if (!StringUtils.IsNull(floorLevelCode))
        {
            insertStatement.Append(", FLOOR_LEVEL_CODE");
            valuesStatement.Append(", :floorLevelCode ");
            parameters.Add(DBUtils.CreateOracleParameter("floorLevelCode", OracleDbType.Varchar2, floorLevelCode));
        }

        if (!StringUtils.IsNull(floorLevelNum))
        {
            insertStatement.Append(", FLOOR_LEVEL_NUM");
            valuesStatement.Append(", :floorLevelNum ");
            parameters.Add(DBUtils.CreateOracleParameter("floorLevelNum", OracleDbType.Varchar2, floorLevelNum));
        }

        if (!StringUtils.IsNull(buildingName))
        {
            insertStatement.Append(", BUILDING_NAME");
            valuesStatement.Append(", :buildingName ");
            parameters.Add(DBUtils.CreateOracleParameter("buildingName", OracleDbType.Varchar2, buildingName));
        }

        if (!StringUtils.IsNull(lotNumber))
        {
            insertStatement.Append(", LOT_NUMBER");
            valuesStatement.Append(", :lotNumber ");
            parameters.Add(DBUtils.CreateOracleParameter("lotNumber", OracleDbType.Varchar2, lotNumber));
        }

        if (!StringUtils.IsNull(streetNumber))
        {
            insertStatement.Append(", STREET_NUMBER");
            valuesStatement.Append(", :streetNumber ");
            parameters.Add(DBUtils.CreateOracleParameter("streetNumber", OracleDbType.Varchar2, streetNumber));
        }

        if (!StringUtils.IsNull(streetName))
        {
            insertStatement.Append(", STREET_NAME");
            valuesStatement.Append(", :streetName ");
            parameters.Add(DBUtils.CreateOracleParameter("streetName", OracleDbType.Varchar2, streetName));
        }

        if (!StringUtils.IsNull(streetTypeCode))
        {
            insertStatement.Append(", STREET_TYPE_CODE");
            valuesStatement.Append(", :streetTypeCode ");
            parameters.Add(DBUtils.CreateOracleParameter("streetTypeCode", OracleDbType.Varchar2, streetTypeCode));
        }

        if (!StringUtils.IsNull(streetSuffixCode))
        {
            insertStatement.Append(", STREET_SUFFIX_CODE");
            valuesStatement.Append(", :streetSuffixCode ");
            parameters.Add(DBUtils.CreateOracleParameter("streetSuffixCode", OracleDbType.Varchar2, streetSuffixCode));
        }

        if (!StringUtils.IsNull(locality))
        {
            insertStatement.Append(", LOCALITY");
            valuesStatement.Append(", :locality");
            parameters.Add(DBUtils.CreateOracleParameter("locality", OracleDbType.Varchar2, locality));
        }

        if (!StringUtils.IsNull(stateCode))
        {
            insertStatement.Append(", STATE_CODE");
            valuesStatement.Append(", :stateCode");
            parameters.Add(DBUtils.CreateOracleParameter("stateCode", OracleDbType.Varchar2, stateCode));
        }

        if (!StringUtils.IsNull(postcode))
        {
            insertStatement.Append(", POSTCODE");
            valuesStatement.Append(", :postcode ");
            parameters.Add(DBUtils.CreateOracleParameter("postcode", OracleDbType.Varchar2, postcode));
        }

        if (!StringUtils.IsNull(country))
        {
            insertStatement.Append(", COUNTRY");
            valuesStatement.Append(", :country ");
            parameters.Add(DBUtils.CreateOracleParameter("country", OracleDbType.Varchar2, country));
        }

        if (!StringUtils.IsNull(esmsAddress))
        {
            insertStatement.Append(", ESMS_ADDRESS");
            valuesStatement.Append(", :esmsAddress ");
            parameters.Add(DBUtils.CreateOracleParameter("esmsAddress", OracleDbType.Varchar2, esmsAddress));
        }

        if (!StringUtils.IsNull(validatedBy))
        {
            insertStatement.Append(", VALIDATED_DATE");
            valuesStatement.Append(", SYSDATE ");
            insertStatement.Append(", VALIDATED_BY");
            valuesStatement.Append(", :validatedBy ");
            parameters.Add(DBUtils.CreateOracleParameter("validatedBy", OracleDbType.Varchar2, validatedBy));
        }


        if (!StringUtils.IsNull(confidence))
        {
            insertStatement.Append(", VALIDATION_CONFIDENCE");
            valuesStatement.Append(", :confidence ");
            parameters.Add(DBUtils.CreateOracleParameter("confidence", OracleDbType.Decimal, confidence));
        }

        if (!StringUtils.IsNull(status))
        {
            insertStatement.Append(", VALIDATION_STATUS");
            valuesStatement.Append(", :status ");
            parameters.Add(DBUtils.CreateOracleParameter("status", OracleDbType.Varchar2, status));
        }

        if (!StringUtils.IsNull(quality))
        {
            insertStatement.Append(", VALIDATION_QUALITY");
            valuesStatement.Append(", :quality ");
            parameters.Add(DBUtils.CreateOracleParameter("quality", OracleDbType.Decimal, quality));
        }

        // finish off the statement
        insertStatement.Append(") ");
        valuesStatement.Append(")");

        // build the insert statement
        string sql = insertStatement + valuesStatement.ToString();

        // Execute the INSERT Statement
        Dml dmlDAO = new Dml();
        int rowsAffected = dmlDAO.Execute(sql, transaction, parameters);

        if (rowsAffected == 0)
        {
            throw new NoRowsAffectedException();
        }
    }

    << many more methods go here >>
}

This system was developed by me and a small team back in 2005 after a 1 week .NET course. Before than my experience was in client-server applications. Over the past 5 years I've come to recognise the benefits of automated unit testing, automated integration testing and automated acceptance testing (using Selenium or equivalent) but the current code-base seems impossible to introduce these concepts.

We are now starting to work on a major enhancement project with tight time-frames. The team consists of 5 .NET developers - 2 developers with a few years of .NET experience and 3 others with little or no .NET experience. None of the team (including myself) has experience in using .NET unit testing or mocking frameworks.

What strategy would you use to make this code cleaner, more object-oriented, testable and maintainable?