重构

http://www.jianshu.com/p/f8cb51bc8e19

http://blog.csdn.net/lovelion/article/details/17970147

http://www.cnblogs.com/draem0507/p/4942939.html

AS 重构
http://www.jianshu.com/p/f8cb51bc8e19
1.封装集合

 public static void main(String[] args) {


        Day1Test day1Test = new Day1Test();

        //获取到了内部对象
        List<String> list = day1Test.getList();

        //肆无忌惮的操作
        list.add("a");

        day1Test.iterator();

        //正确的做法
        Day1Test2 day1Test2 = new Day1Test2();

        //获取到了内部对象
        List<String> list2 = day1Test2.getList();

        //肆无忌惮的操作
        list2.add("a");

        day1Test2.iterator();


    }


    static class Day1Test {


        private List<String> list = new ArrayList<String>();

        public List getList() {


            return list;


        }

        //模拟不暴露给外部
        protected void add(String value) {
            list.add(value);

        }

        protected void remove(String value) {

            list.remove(value);
        }


        public void iterator() {

            for (String str : list) {
                System.out.println(str);
            }

        }

    }

    static class Day1Test2 {


        private List<String> list = new ArrayList<String>();

        public List getList() {


            return new ArrayList(list);


        }

        //模拟不暴露给外部
        protected void add(String value) {
            list.add(value);

        }

        protected void remove(String value) {

            list.remove(value);
        }


        public void iterator() {

            for (String str : list) {
                System.out.println(str);
            }

        }

    }

2.移动方法

class BankAccount {
    public BankAccount(int accountAge, int creditScore, AccountInterest accountInterest) {
        AccountAge = accountAge;
        CreditScore = creditScore;
        AccountInterest = accountInterest;
    }

    public int AccountAge;
    public int CreditScore;
    public AccountInterest AccountInterest;

    //这个方法跟BankAccount没有直接关系
    public double CalculateInterestRate() {
        if (CreditScore > 800)
            return 0.02;

        if (AccountAge > 10)
            return 0.03;

        return 0.05;
    }
}

class AccountInterest {
    public BankAccount Account;

    public AccountInterest(BankAccount account) {
        Account = account;
    }

    public double InterestRate() {
        return Account.CalculateInterestRate();
    }

    public boolean IntroductoryRate() {
        {
            return Account.CalculateInterestRate() < 0.05;
        }
    }
}

class BankAccount1
{
    public BankAccount1(int accountAge, int creditScore, AccountInterest1 accountInterest)
    {
        AccountAge = accountAge;
        CreditScore = creditScore;
        AccountInterest1 = accountInterest;
    }

    public int AccountAge ;
    public int CreditScore;
    public AccountInterest1 AccountInterest1 ;
}

 class AccountInterest1
{
    public BankAccount1 Account ;

    public AccountInterest1(BankAccount1 account)
    {
        Account = account;
    }

    public double InterestRate()
    {
        return CalculateInterestRate();
    }

    public boolean IntroductoryRate()
    {
       return CalculateInterestRate() < 0.05;
    }

    public double CalculateInterestRate()
    {
        if (Account.CreditScore > 800)
            return 0.02;

        if (Account.AccountAge > 10)
            return 0.03;

        return 0.05;
    }
}

3.提升方法

简单点说，如果子类都有相同的方法，那就应该将方法提上到父类层
abstract class Vehicle {
        // other methods
    }

    class Car extends Vehicle {
        public void Turn(String str) {
            // code here
        }
    }

    public class Motorcycle extends Vehicle {
        public void Turn(String str) {
            // code here
        }
    }

提升后的结构
   abstract class Vehicle1 {
        public void Turn(String str) {
            // code here
        }
    }

    class Car1 extends Vehicle1 {
      
    }

    public class Motorcycle1 extends Vehicle1 {

    }

4.下移方法

与第三个上升方法相比，有时候，父类的方法，随着业务的变化，只适合部分子类的时候，则需要将父类的方法下移到具体需要的子类中，这样才符合接口最小原则^^
 abstract class Animal {
        //狗吠
        public void Bark() {
            // code to bark
        }
    }

    class Dog extends Animal {
    }

    class Cat extends Animal {
    }

正常小猫是不会狗吠的，当然，有些接口可能当初定义的时候，有些子类还未出现，因此不会有这样的问题。随着业务的增加，这样的问题出现了，那么，我们就要及时的将接口下移
abstract class Animal1 {
        
    }

    class Dog1 extends Animal1 {

        //狗吠
        public void Bark() {
            // code to bark
        }
    }

    class Cat1 extends Animal1 {
    }

5.提升字段 6.下移字段 同方法

7.重命名(类、方法、参数)
demo就不上，只提一点，命名规则不要担心太长，而选择简写，这样反而为后期的维护带来麻烦。