From b807790cd196d8ed4cab5915ba8d0cad44132b5e Mon Sep 17 00:00:00 2001
From: haerong22 <haerong22@naver.com>
Date: Tue, 15 Mar 2022 11:36:42 +0900
Subject: [PATCH] refactoring : divergent change - split phase

---
 .../_24_split_phase/PriceData.java            |  4 ++
 .../_24_split_phase/PriceOrder.java           | 25 ++++++++++++
 .../_24_split_phase/Product.java              |  5 +++
 .../_24_split_phase/ShippingMethod.java       |  4 ++
 .../_24_split_phase/_before/PriceOrder.java   | 15 +++++++
 .../_24_split_phase/_before/Product.java      |  5 +++
 .../_before/ShippingMethod.java               |  4 ++
 .../_24_split_phase/PriceOrderTest.java       | 40 +++++++++++++++++++
 8 files changed, 102 insertions(+)
 create mode 100644 refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceData.java
 create mode 100644 refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceOrder.java
 create mode 100644 refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/Product.java
 create mode 100644 refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/ShippingMethod.java
 create mode 100644 refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/PriceOrder.java
 create mode 100644 refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/Product.java
 create mode 100644 refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/ShippingMethod.java
 create mode 100644 refactoring/src/test/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceOrderTest.java

diff --git a/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceData.java b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceData.java
new file mode 100644
index 00000000..4f05e0b0
--- /dev/null
+++ b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceData.java
@@ -0,0 +1,4 @@
+package com.example.refactoring._07_divergent_change._24_split_phase;
+
+public record PriceData(double basePrice, double discount, int quantity) {
+}
diff --git a/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceOrder.java b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceOrder.java
new file mode 100644
index 00000000..abece070
--- /dev/null
+++ b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceOrder.java
@@ -0,0 +1,25 @@
+package com.example.refactoring._07_divergent_change._24_split_phase;
+
+public class PriceOrder {
+
+    public double priceOrder(Product product, int quantity, ShippingMethod shippingMethod) {
+        final PriceData priceData = calculatePriceData(product, quantity);
+
+        return applyShipping(priceData, shippingMethod);
+    }
+
+    private PriceData calculatePriceData(Product product, int quantity) {
+        final double basePrice = product.basePrice() * quantity;
+        final double discount = Math.max(quantity - product.discountThreshold(), 0)
+                * product.basePrice() * product.discountRate();
+
+        return new PriceData(basePrice, discount, quantity);
+    }
+
+    private double applyShipping(PriceData priceData, ShippingMethod shippingMethod) {
+        final double shippingPerCase = (priceData.basePrice() > shippingMethod.discountThreshold()) ?
+                shippingMethod.discountedFee() : shippingMethod.feePerCase();
+        final double shippingCost = priceData.quantity() * shippingPerCase;
+        return priceData.basePrice() - priceData.discount() + shippingCost;
+    }
+}
diff --git a/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/Product.java b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/Product.java
new file mode 100644
index 00000000..971c6596
--- /dev/null
+++ b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/Product.java
@@ -0,0 +1,5 @@
+package com.example.refactoring._07_divergent_change._24_split_phase;
+
+public record Product(double basePrice, double discountThreshold, double discountRate) {
+
+}
diff --git a/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/ShippingMethod.java b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/ShippingMethod.java
new file mode 100644
index 00000000..e24129aa
--- /dev/null
+++ b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/ShippingMethod.java
@@ -0,0 +1,4 @@
+package com.example.refactoring._07_divergent_change._24_split_phase;
+
+public record ShippingMethod(double discountThreshold, double discountedFee, double feePerCase) {
+}
\ No newline at end of file
diff --git a/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/PriceOrder.java b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/PriceOrder.java
new file mode 100644
index 00000000..61229927
--- /dev/null
+++ b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/PriceOrder.java
@@ -0,0 +1,15 @@
+package com.example.refactoring._07_divergent_change._24_split_phase._before;
+
+public class PriceOrder {
+
+    public double priceOrder(Product product, int quantity, ShippingMethod shippingMethod) {
+        final double basePrice = product.basePrice() * quantity;
+        final double discount = Math.max(quantity - product.discountThreshold(), 0)
+                * product.basePrice() * product.discountRate();
+        final double shippingPerCase = (basePrice > shippingMethod.discountThreshold()) ?
+                shippingMethod.discountedFee() : shippingMethod.feePerCase();
+        final double shippingCost = quantity * shippingPerCase;
+        final double price = basePrice - discount + shippingCost;
+        return price;
+    }
+}
diff --git a/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/Product.java b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/Product.java
new file mode 100644
index 00000000..14cea22e
--- /dev/null
+++ b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/Product.java
@@ -0,0 +1,5 @@
+package com.example.refactoring._07_divergent_change._24_split_phase._before;
+
+public record Product(double basePrice, double discountThreshold, double discountRate) {
+
+}
diff --git a/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/ShippingMethod.java b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/ShippingMethod.java
new file mode 100644
index 00000000..d16331ff
--- /dev/null
+++ b/refactoring/src/main/java/com/example/refactoring/_07_divergent_change/_24_split_phase/_before/ShippingMethod.java
@@ -0,0 +1,4 @@
+package com.example.refactoring._07_divergent_change._24_split_phase._before;
+
+public record ShippingMethod(double discountThreshold, double discountedFee, double feePerCase) {
+}
\ No newline at end of file
diff --git a/refactoring/src/test/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceOrderTest.java b/refactoring/src/test/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceOrderTest.java
new file mode 100644
index 00000000..8ca898da
--- /dev/null
+++ b/refactoring/src/test/java/com/example/refactoring/_07_divergent_change/_24_split_phase/PriceOrderTest.java
@@ -0,0 +1,40 @@
+package com.example.refactoring._07_divergent_change._24_split_phase;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class PriceOrderTest {
+
+    @Test
+    void priceOrder_discountedFee() {
+        PriceOrder priceOrder = new PriceOrder();
+        double price = priceOrder.priceOrder(new Product(10, 2, 0.5),
+                4,
+                new ShippingMethod(20, 1, 5));
+
+        // basePrice = 10 * 4 = 40
+        // discount = 2 * 10 * 0.5 = 10
+        // shippingPerCase = 1 (40 > 20)
+        // shippingCost = 4 * 1 = 4
+        // price = 40 - 10 + 4 = 34
+
+        assertEquals(34, price);
+    }
+
+    @Test
+    void priceOrder_feePerCase() {
+        PriceOrder priceOrder = new PriceOrder();
+        double price = priceOrder.priceOrder(new Product(10, 2, 0.5),
+                2,
+                new ShippingMethod(20, 1, 5));
+
+        // basePrice = 10 * 2 = 20
+        // discount = 0 * 10 * 0.5 = 0
+        // shippingPerCase = 5
+        // shippingCost = 2 * 5 = 10
+        // price = 20 - 0 + 10 = 30
+
+        assertEquals(30, price);
+    }
+}
\ No newline at end of file