Step by step. Net code refactoring study note 11

Step by step. Net code refactoring learning notes Series

Step by step. Net code refactoring

Step by step. Net code refactoring Study Notes II. Extraction Method (Extract Method)

Step by step. Net code refactoring study note 3. inline Method)

Step by step. Net code refactoring Study Notes 4. Temporary variables (temporary variable)

Step by step. Net code refactoring study note 5. decomposition functions and replacement algorithms (replace method and substitute algorithm)

Step by step. Net code refactoring study note 6. Move method and move field)

Step by step. Net code refactoring study note 7

Step by step. Net code refactoring learning notes 8

Step by step. Net code refactoring study note 9

Step by step. Net code refactoring study note 10

 

1. Remove control flag (remove control flag)

Motivation)

Replace the control mark with a break or return statement.

Example

        public void CheckSecurity(string[] people)        {            string found = string.Empty;            for (int i = 0; i < people.Length; i++)            {                if (found.Equals(""))                {                    if (people[i].Equals("Don"))                    {                        found = "Don";                    }                    if (people[i].Equals("John"))                    {                        found = "John";                    }                }            }            SomeDataCode(found);        }

Change

        public void CheckSecurity(string[] people)        {            string found = string.Empty;            for (int i = 0; i < people.Length; i++)            {                if (found.Equals(""))                {                    if (people[i].Equals("Don"))                    {                        found = "Don";                        break;                    }                    if (people[i].Equals("John"))                    {                        found = "John";                        break;                    }                }            }            SomeDataCode(found);        }

Example

        public string FindPeople(string[] people)        {            string found = string.Empty;            for (int i = 0; i < people.Length; i++)            {                if (found.Equals(""))                {                    if (people[i].Equals("Don"))                    {                        found = "Don";                                          }                    if (people[i].Equals("John"))                    {                        found = "John";                                          }                }            }            return found;        }

Change

        public string FindPeople(string[] people)        {            string found = string.Empty;            for (int i = 0; i < people.Length; i++)            {                if (found.Equals(""))                {                    if (people[i].Equals("Don"))                    {                        return "Don";                    }                    if (people[i].Equals("John"))                    {                        return "John";                    }                }            }            return string.Empty;        }

Ii. Replace nested conditional with guard clauses (replace nested conditional statements with guard statements)

Motivation)

The guard clause (guard clses) represents all special cases.

Example

        public double GetPayAmount()        {            double result;            if (IsDead)                result = DeadAmount();            else            {                if (IsSeparated)                    result = SeparatedAmount();                else                {                    if (IsRetired)                        result = RetiredPayAmount();                    else                        result = NormalPayAmount();                }            }            return result;        }

Change

        public double GetPayAmount()        {            if (IsDead)                return DeadAmount();            if (IsSeparated)                return SeparatedAmount();            if (IsRetired)                return RetiredPayAmount();            return NormalPayAmount();        }

Iii. Introduce Null Object (introducing Null Object)

Motivation)

Replace null value (invalid value) with Null Object (Invalid object)

Example

            if (customer == null)                plan = BillingPlan.Basic();            else                plan = customer.GetPlan();

Change

        public double GetPayAmount()        {            if (customer.IsNull())                plan = BillingPlan.Basic();            else                plan = customer.GetPlan();        }

Iv. Rename method (rename function)

Motivation)

Modifying the function name makes it easy for people to understand its role.

Example

        public int Getinvcdtlmt()        {            return 10;        }

Change

        public int GetInvoiceAbleCreditLimit()        {            return 10;        }

5. Separate query from modifier (separate the query function from the modification function)

Motivation)

Create two different functions, one for query and the other for modification.

Example

        public string FindPeople(string[] people)        {            string found = string.Empty;            for (int i = 0; i < people.Length; i++)            {                if (found.Equals(""))                {                    if (people[i].Equals("Don"))                    {                        SendMail();                        return "Don";                    }                    if (people[i].Equals("John"))                    {                        SendMail();                        return "John";                    }                }            }            return string.Empty;        }

Change

        public string FindPeople(string[] people)        {            string found = FindPeopleOne(people);            SendMailToPeople(found);        }        public string FindPeopleOne(string[] people)        {            string found = string.Empty;            for (int i = 0; i < people.Length; i++)            {                if (found.Equals(""))                {                    if (people[i].Equals("Don"))                    {                        return "Don";                    }                    if (people[i].Equals("John"))                    {                        return "John";                    }                }            }            return string.Empty;        }        public void SendMailToPeople(string people)        {            if (!string.IsNullOrEmpty(people))                SendMail();        }

Vi. parameterize method (parameters included in the function)

Motivation)

Create a single function to express those different values with Parameters

Example

        public double TenPercentRaise()        {            return salary * 1.1;        }        public double FivePercentRaise()        {            return salary * 1.05;        }

Change

        public double Raise(double factor)        {            return salary * factor;        }

VII. Replace parameter with explicit methods (replace the parameter with a definite function)

Motivation)

Create an independent function for each possible value of this parameter.

Example

        private int _height;        private int _width;        public void SetValue(string name, int value)        {            if (name.Equals("height"))            {                _height = value;                return;            }            if (name.Equals("width"))            {                _width = value;                return;            }        }

Change

        private int _height;        private int _width;        public int Height        {            set { _height = value; }        }        public int Width        {            set { _width = value; }        }