feat : SOLID - LSP 샘플 코드 구현

놀이터(예제 코드 작성)/solid-design-pattern-sample/README.md

@@ -28,6 +28,15 @@
 - 쿠폰 결제방식을 추가한다고 가정한다.
 - 쿠폰으로 결제할 경우 잔고가 차감되지 않는다.
 
+### LSP(Liskov Substitution Principle)
+
+- 리스코프 치환 원칙
+- 프로그램의 객체는 프로그램의 정확성을 깨뜨리지 않으면서 하위 타입의 인스턴스로 바꿀 수 있어야 한다.
+
+#### 구현 요구사항
+
+- 좌표를 입력하면 해당 좌표로 이동수단의 위치가 변한다.
+
 ## 참고자료
 
 - [SOLID (객체 지향 설계)](https://ko.wikipedia.org/wiki/SOLID_(%EA%B0%9D%EC%B2%B4_%EC%A7%80%ED%96%A5_%EC%84%A4%EA%B3%84)) 

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/after/CarVehicleServiceAfter.kt

@@ -0,0 +1,24 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.after
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.Vehicle
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleMoveRequest
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleRepository
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleType
+import org.springframework.stereotype.Service
+
+@Service
+class CarVehicleServiceAfter(
+    private val vehicleRepository: VehicleRepository
+): VehicleServiceAfter() {
+    override fun move(request: VehicleMoveRequest): Vehicle {
+        println("자동차가 이동합니다.")
+        val vehicle = vehicleRepository.getVehicle(request.vehicleId)
+        vehicle.positionX = request.positionX
+        vehicle.positionY = request.positionY
+        return vehicle
+    }
+
+    override fun vehicleType(): VehicleType {
+        return VehicleType.CAR
+    }
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/after/PlaneVehicleServiceAfter.kt

@@ -0,0 +1,24 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.after
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.Vehicle
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleMoveRequest
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleRepository
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleType
+import org.springframework.stereotype.Service
+
+@Service
+class PlaneVehicleServiceAfter(
+    private val vehicleRepository: VehicleRepository
+): VehicleServiceAfter() {
+    override fun move(request: VehicleMoveRequest): Vehicle {
+        println("비행기가 이동합니다.")
+        val vehicle = vehicleRepository.getVehicle(request.vehicleId)
+        vehicle.positionX = request.positionX
+        vehicle.positionY = request.positionY
+        return vehicle
+    }
+
+    override fun vehicleType(): VehicleType {
+        return VehicleType.PLANE
+    }
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/after/VehicleControllerAfter.kt

@@ -0,0 +1,20 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.after
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.Vehicle
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleMoveRequest
+import org.springframework.web.bind.annotation.PatchMapping
+import org.springframework.web.bind.annotation.RequestBody
+import org.springframework.web.bind.annotation.RequestMapping
+import org.springframework.web.bind.annotation.RestController
+
+@RequestMapping("/vehicles")
+@RestController
+class VehicleControllerAfter(
+    private val vehicleServiceFactoryAfter: VehicleServiceFactoryAfter
+) {
+    @PatchMapping("/with-lsp")
+    fun move(@RequestBody request: VehicleMoveRequest): Vehicle {
+        val vehicleServiceAfter = vehicleServiceFactoryAfter.getVehicleServiceAfter(request.vehicleType)
+        return vehicleServiceAfter.move(request)
+    }
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/after/VehicleServiceAfter.kt

@@ -0,0 +1,11 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.after
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.Vehicle
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleMoveRequest
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleType
+
+abstract class VehicleServiceAfter {
+    abstract fun move(request: VehicleMoveRequest): Vehicle
+
+    abstract fun vehicleType(): VehicleType
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/after/VehicleServiceFactoryAfter.kt

@@ -0,0 +1,14 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.after
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleType
+import org.springframework.stereotype.Component
+
+@Component
+class VehicleServiceFactoryAfter(
+    val vehicleServiceAfters: List<VehicleServiceAfter>
+) {
+    fun getVehicleServiceAfter(vehicleType: VehicleType): VehicleServiceAfter {
+        return vehicleServiceAfters.find { it.vehicleType() == vehicleType }
+            ?: throw NoSuchElementException("해당 이동수단에 대한 구현이 존재하지 않습니다.")
+    }
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/before/CarVehicleServiceBefore.kt

@@ -0,0 +1,23 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.before
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.Vehicle
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleMoveRequest
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleRepository
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleType
+import org.springframework.stereotype.Service
+
+@Service
+class CarVehicleServiceBefore(
+    private val vehicleRepository: VehicleRepository
+) : VehicleServiceBefore(vehicleRepository) {
+    override fun move(request: VehicleMoveRequest): Vehicle {
+        val vehicle = vehicleRepository.getVehicle(request.vehicleId)
+        vehicle.positionX += request.positionX // 하위 타입에서의 잘못된 오버라이딩!
+        vehicle.positionY += request.positionY // 하위 타입에서의 잘못된 오버라이딩!
+        return vehicle
+    }
+
+    override fun vehicleType(): VehicleType {
+        return VehicleType.CAR
+    }
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/before/PlaneVehicleServiceBefore.kt

@@ -0,0 +1,23 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.before
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.Vehicle
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleMoveRequest
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleRepository
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleType
+import org.springframework.stereotype.Service
+
+@Service
+class PlaneVehicleServiceBefore(
+    private val vehicleRepository: VehicleRepository
+) : VehicleServiceBefore(vehicleRepository) {
+    override fun move(request: VehicleMoveRequest): Vehicle {
+        val vehicle = vehicleRepository.getVehicle(request.vehicleId)
+        vehicle.positionX -= request.positionX // 하위 타입에서의 잘못된 오버라이딩!
+        vehicle.positionY -= request.positionY // 하위 타입에서의 잘못된 오버라이딩!
+        return vehicle
+    }
+
+    override fun vehicleType(): VehicleType {
+        return VehicleType.PLANE
+    }
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/before/VehicleControllerBefore.kt

@@ -0,0 +1,20 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.before
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.Vehicle
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleMoveRequest
+import org.springframework.web.bind.annotation.PatchMapping
+import org.springframework.web.bind.annotation.RequestBody
+import org.springframework.web.bind.annotation.RequestMapping
+import org.springframework.web.bind.annotation.RestController
+
+@RequestMapping("/vehicles")
+@RestController
+class VehicleControllerBefore(
+    private val vehicleServiceFactoryBefore: VehicleServiceFactoryBefore
+) {
+    @PatchMapping("/none-lsp")
+    fun move(@RequestBody request: VehicleMoveRequest): Vehicle {
+        val vehicleServiceBefore = vehicleServiceFactoryBefore.getVehicleServiceBefore(request.vehicleType)
+        return vehicleServiceBefore.move(request)
+    }
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/before/VehicleServiceBefore.kt

@@ -0,0 +1,19 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.before
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.Vehicle
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleMoveRequest
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleRepository
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleType
+
+abstract class VehicleServiceBefore(
+    private val vehicleRepository: VehicleRepository
+) {
+    open fun move(request: VehicleMoveRequest): Vehicle {
+        val vehicle = vehicleRepository.getVehicle(request.vehicleId)
+        vehicle.positionX = request.positionX
+        vehicle.positionY = request.positionY
+        return vehicle
+    }
+
+    abstract fun vehicleType(): VehicleType
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/before/VehicleServiceFactoryBefore.kt

@@ -0,0 +1,14 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.before
+
+import com.banjjoknim.soliddesignpatternsample.solid.lsp.common.VehicleType
+import org.springframework.stereotype.Component
+
+@Component
+class VehicleServiceFactoryBefore(
+    val vehicleServiceBefores: List<VehicleServiceBefore>
+) {
+    fun getVehicleServiceBefore(vehicleType: VehicleType): VehicleServiceBefore {
+        return vehicleServiceBefores.find { it.vehicleType() == vehicleType }
+            ?: throw NoSuchElementException("해당 이동수단에 대한 구현이 존재하지 않습니다.")
+    }
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/common/Vehicle.kt

@@ -0,0 +1,12 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.common
+
+import javax.persistence.Entity
+import javax.persistence.Id
+
+@Entity
+class Vehicle(
+    var positionX: Int = 0,
+    var positionY: Int = 0,
+    @Id
+    val id: Long = 0L
+)

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/common/VehicleMoveRequest.kt

@@ -0,0 +1,8 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.common
+
+data class VehicleMoveRequest(
+    val vehicleId: Long,
+    val positionX: Int,
+    val positionY: Int,
+    val vehicleType: VehicleType
+)

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/common/VehicleRepository.kt

@@ -0,0 +1,5 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.common
+
+interface VehicleRepository {
+    fun getVehicle(vehicleId: Long): Vehicle
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/common/VehicleRepositoryStub.kt

@@ -0,0 +1,10 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.common
+
+import org.springframework.stereotype.Repository
+
+@Repository
+class VehicleRepositoryStub : VehicleRepository {
+    override fun getVehicle(vehicleId: Long): Vehicle {
+        return Vehicle(id = vehicleId)
+    }
+}

놀이터(예제 코드 작성)/solid-design-pattern-sample/src/main/kotlin/com/banjjoknim/soliddesignpatternsample/solid/lsp/common/VehicleType.kt

@@ -0,0 +1,6 @@
+package com.banjjoknim.soliddesignpatternsample.solid.lsp.common
+
+enum class VehicleType {
+    CAR,
+    PLANE
+}