refactoring : long parameter list - remove flag argument

refactoring/src/main/java/com/example/refactoring/_04_long_parameter_list/_15_remove_flag_argument/Order.java

@@ -0,0 +1,22 @@
+package com.example.refactoring._04_long_parameter_list._15_remove_flag_argument;
+
+import java.time.LocalDate;
+
+public class Order {
+
+    private LocalDate placedOn;
+    private String deliveryState;
+
+    public Order(LocalDate placedOn, String deliveryState) {
+        this.placedOn = placedOn;
+        this.deliveryState = deliveryState;
+    }
+
+    public LocalDate getPlacedOn() {
+        return placedOn;
+    }
+
+    public String getDeliveryState() {
+        return deliveryState;
+    }
+}

refactoring/src/main/java/com/example/refactoring/_04_long_parameter_list/_15_remove_flag_argument/Shipment.java

@@ -0,0 +1,32 @@
+package com.example.refactoring._04_long_parameter_list._15_remove_flag_argument;
+
+import java.time.LocalDate;
+
+public class Shipment {
+
+    public LocalDate deliveryDate(Order order, boolean isRush) {
+        if (isRush) {
+            return rushDeliveryDate(order);
+        } else {
+            return regularDeliveryDate(order);
+        }
+    }
+
+    public LocalDate regularDeliveryDate(Order order) {
+        int deliveryTime = switch (order.getDeliveryState()) {
+            case "WA", "CA" -> 2;
+            case "OR", "TX", "NY" -> 3;
+            default -> 4;
+        };
+        return order.getPlacedOn().plusDays(deliveryTime);
+    }
+
+    public LocalDate rushDeliveryDate(Order order) {
+        int deliveryTime = switch (order.getDeliveryState()) {
+            case "WA", "CA", "OR" -> 1;
+            case "TX", "NY", "FL" -> 2;
+            default -> 3;
+        };
+        return order.getPlacedOn().plusDays(deliveryTime);
+    }
+}

refactoring/src/test/java/com/example/refactoring/_04_long_parameter_list/_15_remove_flag_argument/ShipmentTest.java

@@ -0,0 +1,21 @@
+package com.example.refactoring._04_long_parameter_list._15_remove_flag_argument;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDate;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class ShipmentTest {
+
+    @Test
+    void deliveryDate() {
+        LocalDate placedOn = LocalDate.of(2021, 12, 15);
+        Order orderFromWA = new Order(placedOn, "WA");
+
+        Shipment shipment = new Shipment();
+        assertEquals(placedOn.plusDays(1), shipment.rushDeliveryDate(orderFromWA)); // flag 파라미터 전달 보다는 메소드 명을 명확하게 한다.
+        assertEquals(placedOn.plusDays(2), shipment.regularDeliveryDate(orderFromWA));
+    }
+
+}