Compare Hexagonal to Layered

.github/workflows/gradle-build.yml

@@ -0,0 +1,35 @@
+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+# This workflow will build a package using Gradle and then publish it to GitHub packages when a release is created
+# For more information see: https://github.com/actions/setup-java/blob/main/docs/advanced-usage.md#Publishing-using-gradle
+
+name: Gradle Build
+
+on:
+  workflow_dispatch
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up JDK 25
+      uses: actions/setup-java@v4
+      with:
+        java-version: '25-ea'
+        distribution: 'temurin'
+        server-id: github # Value of the distributionManagement/repository/id field of the pom.xml
+        settings-path: ${{ github.workspace }} # location for the settings.xml file
+
+    - name: Setup Gradle
+      uses: gradle/actions/setup-gradle@af1da67850ed9a4cedd57bfd976089dd991e2582 # v4.0.0
+
+    - name: Build with Gradle
+      run: ./gradlew build

README.md

@@ -1,2 +1,7 @@
-# fun-vs-framework
-Demo project for my talk: Fucntional Principles vs the Framework
+[![Gradle Build](https://github.com/tibtof/fun-vs-framework/actions/workflows/gradle-build.yml/badge.svg)](https://github.com/tibtof/fun-vs-framework/actions/workflows/gradle-build.yml)
+
+# Own your design: functional principles vs the framework
+
+Demo project to showcase the refactoring of a Spring Boot application from a layered architecture to a hexagonal architecture. The _main_ branch contains the refactored solution. There are also individual branches for each architectural approach: [layered](https://github.com/tibtof/fun-vs-framework/tree/layered) and [hexagonal](https://github.com/tibtof/fun-vs-framework/tree/hexagonal), with a [PR that highlights the changes](https://github.com/tibtof/fun-vs-framework/pull/2).
+
+To better understand the context I recomend [watching my talk](https://www.youtube.com/watch?v=kqNDeq-DrVM) and going over the slides.

build.gradle.kts

@@ -1,45 +1,55 @@
+val springCloudVersion: String by project
+val springKafkaVersion: String by project
+val postgresqlVersion: String by project
+val wiremockTestcontainersVersion: String by project
+val junitPlatformLauncherVersion: String by project
+val mockitoCoreVersion: String by project
+val archunitVersion: String by project
+val openFeignVersion: String by project
+val springBootTestcontainersVersion: String by project
+val testcontainersVersion: String by project
+
 plugins {
 	java
-	id("org.springframework.boot") version "3.4.3"
-	id("io.spring.dependency-management") version "1.1.7"
+	id("org.springframework.boot")
+	id("io.spring.dependency-management")
 }
 
 group = "fun.vs.fw"
 version = "0.0.1-SNAPSHOT"
 
 java {
 	toolchain {
-		languageVersion = JavaLanguageVersion.of(23)
+		languageVersion = JavaLanguageVersion.of(25)
 	}
 }
 
 repositories {
 	mavenCentral()
 }
 
-extra["springCloudVersion"] = "2024.0.0"
-
 dependencies {
 	implementation("org.springframework.boot:spring-boot-starter-data-jpa")
 	implementation("org.springframework.boot:spring-boot-starter-web")
 	implementation("org.springframework.cloud:spring-cloud-starter-openfeign")
-	implementation("org.springframework.kafka:spring-kafka")
-    implementation("org.postgresql:postgresql:42.7.5")
-
-	testImplementation("org.springframework.boot:spring-boot-starter-test")
-	testImplementation("org.springframework.boot:spring-boot-testcontainers")
-	testImplementation("org.springframework.kafka:spring-kafka-test")
-	testImplementation("org.testcontainers:junit-jupiter")
-	testImplementation("org.testcontainers:postgresql")
-	testImplementation("org.testcontainers:kafka")
-    testImplementation("org.wiremock.integrations.testcontainers:wiremock-testcontainers-module:1.0-alpha-14")
-    testRuntimeOnly("org.junit.platform:junit-platform-launcher")
-    testImplementation("org.mockito:mockito-core:5.16.0")
+	implementation("org.springframework.kafka:spring-kafka:")
+	implementation("org.postgresql:postgresql:$postgresqlVersion")
+
+    testImplementation("org.springframework.boot:spring-boot-starter-test")
+    testImplementation("org.springframework.boot:spring-boot-testcontainers")
+    testImplementation("org.springframework.kafka:spring-kafka-test")
+    testImplementation("org.testcontainers:junit-jupiter")
+    testImplementation("org.testcontainers:postgresql")
+    testImplementation("org.testcontainers:kafka")
+    testImplementation("org.wiremock.integrations.testcontainers:wiremock-testcontainers-module:$wiremockTestcontainersVersion")
+	testRuntimeOnly("org.junit.platform:junit-platform-launcher")
+	testImplementation("org.mockito:mockito-core:$mockitoCoreVersion")
+	testImplementation("com.tngtech.archunit:archunit:$archunitVersion")
 }
 
 dependencyManagement {
 	imports {
-		mavenBom("org.springframework.cloud:spring-cloud-dependencies:${property("springCloudVersion")}")
+		mavenBom("org.springframework.cloud:spring-cloud-dependencies:$springCloudVersion")
 	}
 }
 

gradle.properties

@@ -0,0 +1,12 @@
+springBootVersion=3.5.6
+springDependencyManagementVersion=1.1.7
+springCloudVersion=2025.0.0
+springKafkaVersion=3.2.2
+postgresqlVersion=42.7.5
+wiremockTestcontainersVersion=1.0-alpha-15
+junitPlatformLauncherVersion=1.10.2
+mockitoCoreVersion=5.20.0
+archunitVersion=1.4.1
+openFeignVersion=4.1.0
+springBootTestcontainersVersion=3.2.2
+testcontainersVersion=1.19.7

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.12.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.1.0-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

settings.gradle.kts

@@ -1 +1,16 @@
+pluginManagement {
+    val springBootVersion: String by settings
+    val springDependencyManagementVersion: String by settings
+
+    repositories {
+        gradlePluginPortal()
+        mavenCentral()
+    }
+
+    plugins {
+        id("org.springframework.boot") version springBootVersion
+        id("io.spring.dependency-management") version springDependencyManagementVersion
+    }
+}
+
 rootProject.name = "fun-vs-fw"

src/main/java/fun/vs/fw/demo/TransactionCategorizationApplication.java

@@ -2,12 +2,8 @@
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.cloud.openfeign.EnableFeignClients;
-import org.springframework.kafka.annotation.EnableKafka;
 
 @SpringBootApplication
-@EnableFeignClients
-@EnableKafka
 public class TransactionCategorizationApplication {
 
     public static void main(String[] args) {

src/main/java/fun/vs/fw/demo/config/TransactionCategorizerConfiguration.java

@@ -0,0 +1,26 @@
+package fun.vs.fw.demo.config;
+
+
+import fun.vs.fw.demo.domain.TransactionCategorizer;
+import fun.vs.fw.demo.jpa.CategorizedTransactionRepositoryAdapter;
+import fun.vs.fw.demo.jpa.TransactionalTransactionCategorizer;
+import fun.vs.fw.demo.merchantdirectory.MerchantDirectoryAdapter;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class TransactionCategorizerConfiguration {
+
+    @Bean
+    public TransactionCategorizer transactionCategorizationService(
+            CategorizedTransactionRepositoryAdapter repositoryAdapter,
+            MerchantDirectoryAdapter merchantDirectoryAdapter) {
+        return new TransactionalTransactionCategorizer(
+                TransactionCategorizer.create(
+                        repositoryAdapter,
+                        repositoryAdapter,
+                        merchantDirectoryAdapter
+                )
+        );
+    }
+}

src/main/java/fun/vs/fw/demo/controller/CategorizedTransactionController.java

@@ -1,9 +1,12 @@
 package fun.vs.fw.demo.controller;
 
 
-import fun.vs.fw.demo.repository.CategorizedTransaction;
-import fun.vs.fw.demo.repository.CategorizedTransactionRepository;
-import fun.vs.fw.demo.repository.CategoryBudget;
+import fun.vs.fw.demo.domain.CategorizedTransaction.ExpenseCategory;
+import fun.vs.fw.demo.domain.CategorizedTransactionPorts.FindBudgetsByCategory;
+import fun.vs.fw.demo.domain.CategorizedTransactionPorts.FindByClientIdAndExpenseCategory;
+import fun.vs.fw.demo.domain.CategorizedTransactionPorts.FindExpenseCategoriesByClient;
+import fun.vs.fw.demo.domain.CategoryBudget;
+import fun.vs.fw.demo.domain.Transaction.ClientId;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestParam;
@@ -12,27 +15,33 @@
 import java.util.List;
 
 @RestController
-public class CategorizedTransactionController {
+public class CategorizedTransactionController<R extends
+        FindByClientIdAndExpenseCategory &
+        FindBudgetsByCategory &
+        FindExpenseCategoriesByClient> {
 
-    private final CategorizedTransactionRepository repository;
+    private final R repository;
 
-    public CategorizedTransactionController(CategorizedTransactionRepository repository) {
+    public CategorizedTransactionController(R repository) {
         this.repository = repository;
     }
 
     @GetMapping("/client/{clientId}/transactions")
-    public List<CategorizedTransaction> getTransactionsByClientAndCategory(@PathVariable String clientId,
-                                                                           @RequestParam String category) {
-        return repository.findByClientIdAndExpenseCategory(clientId, category);
+    public List<CategorizedTransactionResponse> getTransactionsByClientAndCategory(
+            @PathVariable String clientId,
+            @RequestParam String category) {
+        return repository.findBy(new ClientId(clientId), new ExpenseCategory(category))
+                .stream().map(CategorizedTransactionResponse::valueOf).toList();
     }
 
     @GetMapping("/client/{clientId}/categories-budget")
     public List<CategoryBudget> getBudgetByCategory(@PathVariable String clientId) {
-        return repository.findBudgetsByCategory(clientId);
+        return repository.findBudgetsByCategory(new ClientId(clientId));
     }
 
     @GetMapping("/client/{clientId}/categories")
     public List<String> getDistinctExpenseCategoriesByClientId(@PathVariable String clientId) {
-        return repository.findDistinctExpenseCategoriesByClientId(clientId);
+        return repository.findExpenseCategoriesBy(new ClientId(clientId))
+                .stream().map(ExpenseCategory::value).toList();
     }
 }

src/main/java/fun/vs/fw/demo/controller/CategorizedTransactionResponse.java

@@ -0,0 +1,16 @@
+package fun.vs.fw.demo.controller;
+
+
+import fun.vs.fw.demo.domain.CategorizedTransaction;
+
+public record CategorizedTransactionResponse(
+        String transactionId,
+        String expenseCategory) {
+
+    public static CategorizedTransactionResponse valueOf(CategorizedTransaction categorizedTransaction) {
+        return new CategorizedTransactionResponse(
+                categorizedTransaction.transactionId().value(),
+                categorizedTransaction.expenseCategory().value()
+        );
+    }
+}

src/main/java/fun/vs/fw/demo/domain/CategorizedTransaction.java

@@ -0,0 +1,48 @@
+package fun.vs.fw.demo.domain;
+
+
+import fun.vs.fw.demo.domain.Transaction.AccountId;
+import fun.vs.fw.demo.domain.Transaction.Amount;
+import fun.vs.fw.demo.domain.Transaction.ClientId;
+import fun.vs.fw.demo.domain.Transaction.TransactionId;
+
+import java.util.Objects;
+
+import static java.util.Objects.requireNonNull;
+
+public record CategorizedTransaction(
+        CategorizedTransactionId id,
+        TransactionId transactionId,
+        ClientId clientId,
+        AccountId accountId,
+        Amount amount,
+        ExpenseCategory expenseCategory) {
+
+    public CategorizedTransaction {
+        requireNonNull(transactionId, "Transaction ID cannot be null");
+        requireNonNull(clientId, "Client ID cannot be null");
+        requireNonNull(accountId, "Account ID cannot be null");
+        requireNonNull(amount, "Transaction Amount cannot be null");
+        requireNonNull(expenseCategory, "Expense Category cannot be null");
+    }
+
+    public CategorizedTransaction withId(CategorizedTransactionId id) {
+        return new CategorizedTransaction(id, transactionId, clientId, accountId, amount, expenseCategory);
+    }
+
+    public record CategorizedTransactionId(Long value) {
+        public CategorizedTransactionId {
+            Objects.requireNonNull(value, "Transaction ID cannot be null");
+        }
+    }
+
+    public record ExpenseCategory(String value) {
+        public ExpenseCategory {
+            requireNonNull(value, "Expense category cannot be null");
+            if (value.isBlank()) {
+                throw new IllegalArgumentException("Expense category cannot be null or blank");
+            }
+        }
+    }
+}
+