Step by step. NET code refactoring study note 13

1. Replace Exception with Test (Replace Exception with Test)

Motivation)

You throw an exception in the face of a [condition that the caller can check in advance. Modify the caller so that the caller can check the caller before calling the function.

Example

01 private Dictionary <int, string> _ values;

02

03 public double GetValueForPeriod (int periodNumber)

04 {

05 try

06 {

07 return _ values [periodNumber];

08}

09 catch

10 {

11 return 0;

12}

13}

 

Change

View sourceprint? 1 private Dictionary <int, string> _ values;

2

3 public double GetValueForPeriod (int periodNumber)

4 {

5 if (_ values. ContainsKey (periodNumber ))

6 return _ values [periodNumber];

7 return 0;

8}

 

 

Ii. Pull Up Field (value range Up)

Motivation)

The two subclasses have the same value range and move this value to the superclass.

Example

01 public abstract class Emplayee

02 {

03

04}

05

06 public class Salesman: Emplayee

07 {

08 private string _ name;

09

10 public string Name

11 {

12 get {return _ name ;}

13 set {_ name = value ;}

14}

15}

16

17 public class Engineer: Emplayee

18 {

19 private string _ name;

20

21 public string Name

22 {

23 get {return _ name ;}

24 set {_ name = value ;}

25}

26}

 

Change

01 public abstract class Emplayee

02 {

03 private string _ name;

04

05 public string Name

06 {

07 get {return _ name ;}

08 set {_ name = value ;}

09}

10}

11

12 public class Salesman: Emplayee

13 {

14

15}

16

17 public class Engineer: Emplayee

18 {

19

20}

 

3. Pull Up Method (function move Up)

Motivation)

Some functions generate identical results in each subclass. Move this function to superclass.

Example

01 public abstract class Emplayee

02 {

03

04}

05

06 public class Salesman: Emplayee

07 {

08 public string GetName ()

09 {

10 return "spring yang ";

11}

12}

13

14 public class Engineer: Emplayee

15 {

16 public string GetName ()

17 {

18 return "spring yang ";

19}

20}

 

Change

01 public abstract class Emplayee

02 {

03 public string GetName ()

04 {

05 return "spring yang ";

06}

07}

08

09 public class Salesman: Emplayee

10 {

11}

12

13 public class Engineer: Emplayee

14 {

15}

 

4. Pull Up Constructor Body (Constructor ontology moving Up)

Motivation)

There are some constructors in each subclass, and their ontology code is almost the same. Create a New constructor in the base and call it in the subclass constructor.

Example

01 public abstract class Emplayee

02 {

03 private string _ ID;

04 private string _ name;

05

06 public string ID

07 {

08 get {return _ ID ;}

09 set {_ ID = value ;}

10}

11

12 public string Name

13 {

14 get {return _ name ;}

15 set {_ name = value ;}

16}

17}

18

19 public class Salesman: Emplayee

20 {

21 public Salesman (string id, string name)

22 {

23 ID = id;

24 Name = name;

25}

26}

 

Change

01 public abstract class Emplayee

02 {

03 private string _ ID;

04 private string _ name;

05

06 public string ID

07 {

08 get {return _ ID ;}

09 set {_ ID = value ;}

10}

11

12 public string Name

13 {

14 get {return _ name ;}

15 set {_ name = value ;}

16}

17

18 public Emplayee (string id, string name)

19 {

20 _ ID = id;

21 _ name = name;

22}

23}

24

25 public class Salesman: Emplayee

26 {

27