重构之以函数对象取代函数

Myth丶恋晨 2022-05-21 04:00 170阅读 0赞

# 以函数对象取代函数 #

### 重构导图 ###

![MWSB7y7.png][]

### 代码 ###

/**
     * 重构前
     */
    class Account {
        int gamma(int inputVal, int quantity, int yearToDate) {
            int importantValue1 = (inputVal + quantity) + delta();
            int importantValue2 = (inputval * yearToDate) + 100;
            if((yearToDate - importantValue1) > 100)
                importantValue2 -= 20;
            int importantValue3 = importantValue2 * 7;
            return importantValue3 - 2 * importantValue1;
        }
    }

/**
     * 以函数对象取代函数后
     */
    class Account {
        int gamma(int inputVal, int quantity, int yearToDate) {
            return new gamma(this, inputVal, quantity, yearToDate);
        }
    }
    
    class Gamma {
        private final Account account;
        private int inputVal;
        private int quantity;
        private int yearToDate;
        private int importantValue1;
        private int importantValue2;
        private int importantValue3;
    
        public Gamma(Account account, int inputVal, int quantity, int yearToDate) {
            this.account = account;
            this.inputVal = inputVal;
            this.quantity = quantity;
            this.yearToDate = yearToDate;
        }
    
        public int compute() {
            importantValue1 = (inputVal + quantity) + account.delta();
            importantValue2 = (inputval * yearToDate) + 100;
            if((yearToDate - importantValue1) > 100)
                importantValue2 -= 20;
            importantValue3 = importantValue2 * 7;
            return importantValue3 - 2 * importantValue1;
        }
    }

/**
     * 提炼函数后
     */
    class Account {
        int gamma(int inputVal, int quantity, int yearToDate) {
            return new gamma(this, inputVal, quantity, yearToDate);
        }
    }
    
    class Gamma {
        private final Account account;
        private int inputVal;
        private int quantity;
        private int yearToDate;
        private int importantValue1;
        private int importantValue2;
        private int importantValue3;
    
        public Gamma(Account account, int inputVal, int quantity, int yearToDate) {
            this.account = account;
            this.inputVal = inputVal;
            this.quantity = quantity;
            this.yearToDate = yearToDate;
        }
    
        public int compute() {
            importantValue1 = (inputVal + quantity) + account.delta();
            importantValue2 = (inputval * yearToDate) + 100;
            importantThing();
            importantValue3 = importantValue2 * 7;
            return importantValue3 - 2 * importantValue1;
        }
    
        private void importantThing() {
            if((yearToDate - importantValue1) > 100)
                importantValue2 -= 20;
        }
    }

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[MWSB7y7.png]: https://i.imgur.com/MWSB7y7.png
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