Reconstruction 2. Replace Type Code with Class (Replace Type Code with Class), 2. replacecode

Reconstruction 2. Replace Type Code with Class (Replace Type Code with Class), 2. replacecode
Scenario

In a class, we often define some type codes, such:

public static final int INVALID=0;public static final int VALID=1;

We can convert these values into a class.

Prerequisites:

Only when the type code is pure data (the type code will not cause behavior changes in the Switch statement) Can you replace it with a class

Code before modification:

Student

Package com. demo. refactor. codetype. before; public class Student {private int id; private String name;/*** status: 0, valid, 1 is INVALID */private int status; public static final int INVALID = 0; public static final int VALID = 1; public Student (int id, String name, int status) {super (); this. id = id; this. name = name; this. status = status;} public int getId () {return id;} public void setId (int id) {this. id = id;} public String getName () {return name;} public void setName (String name) {this. name = name;} public int getStatus () {return status;} public void setStatus (int status) {this. status = status ;}@ Overridepublic String toString () {return "Student [id =" + id + ", name =" + name + ", status = "+ status +"] ";}}

Test:

Package com. demo. refactor. codetype. before; public class StudentTest {/*** @ param args */public static void main (String [] args) {Student student = new Student (1, "James", Student. VALID); System. out. println (student );}}

After modification:

StatusCode

package com.demo.refactor.codetype.after;public class StatusCode {public static final StatusCode invalid=new StatusCode(0);public static final StatusCode valid=new StatusCode(1);public static final StatusCode[] codes={invalid,valid};private int code;private StatusCode(int code) {this.code = code;}/** * @param index  * @return */public static StatusCode create(int index){return codes[index];}public int getCode() {return code;}public void setCode(int code) {this.code = code;}@Overridepublic String toString() {return "StatusCode [code=" + code + "]";}}

Student

package com.demo.refactor.codetype.after;public class Student {private int id;private String name;private StatusCode code;public Student(int id, String name, StatusCode code) {this.id = id;this.name = name;this.code = code;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getCode() {return code.getCode();}public void setCode(int index) {this.code =StatusCode.create(index);}@Overridepublic String toString() {return "Student [id=" + id + ", name=" + name + ", code=" + code + "]";}}

StudentTest

Package com. demo. refactor. codetype. after; public class StudentTest {/*** @ param args */public static void main (String [] args) {Student stu = new Student (1, "Li Si", StatusCode. invalid); System. out. println (stu );}}