iulian.manda@gmail evaluation article "A quick and practical example of Hexagonal Architecture in Java"

patterns/hexagonal/pom.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>hexagonal</artifactId>
+    <version>1.0</version>
+    <name>hexagonal</name>
+    <description>A quick and practical example of Hexagonal Architecture in Java</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-java</relativePath>
+    </parent>
+
+</project>

patterns/hexagonal/src/main/java/com/baeldung/pattern/hexagonal/WeatherForecasterApp.java

@@ -0,0 +1,17 @@
+package com.baeldung.pattern.hexagonal;
+
+import com.baeldung.pattern.hexagonal.repository.RepositoryFactory;
+import com.baeldung.pattern.hexagonal.repository.WeatherRepository;
+import com.baeldung.pattern.hexagonal.service.WeatherForecasterService;
+import com.baeldung.pattern.hexagonal.ui.WeatherForecasterConsoleUI;
+import com.baeldung.pattern.hexagonal.ui.WeatherForecasterUI;
+
+public class WeatherForecasterApp {
+    public static void main(String[] args) {
+        WeatherRepository repository = RepositoryFactory.getMockWeatherRepository();
+        WeatherForecasterService service = new WeatherForecasterService(repository);
+        WeatherForecasterUI ui = new WeatherForecasterConsoleUI(service);
+
+        ui.start();
+    }
+}

patterns/hexagonal/src/main/java/com/baeldung/pattern/hexagonal/repository/MockWeatherRepository.java

@@ -0,0 +1,17 @@
+package com.baeldung.pattern.hexagonal.repository;
+
+public class MockWeatherRepository implements WeatherRepository {
+    @Override
+    public double getTemperature(String location) {
+        switch (location) {
+        case "cluj-napoca":
+            return 17;
+        case "bucharest":
+            return 22;
+        case "new york":
+            return 15;
+        default:
+            return 20;
+        }
+    }
+}

patterns/hexagonal/src/main/java/com/baeldung/pattern/hexagonal/repository/RepositoryFactory.java

@@ -0,0 +1,11 @@
+package com.baeldung.pattern.hexagonal.repository;
+
+public class RepositoryFactory {
+    private RepositoryFactory() {
+        super();
+    }
+
+    public static WeatherRepository getMockWeatherRepository() {
+        return new MockWeatherRepository();
+    }
+}

patterns/hexagonal/src/main/java/com/baeldung/pattern/hexagonal/repository/WeatherRepository.java

@@ -0,0 +1,5 @@
+package com.baeldung.pattern.hexagonal.repository;
+
+public interface WeatherRepository {
+    double getTemperature(String location);
+}

patterns/hexagonal/src/main/java/com/baeldung/pattern/hexagonal/service/WeatherForecasterService.java

@@ -0,0 +1,20 @@
+package com.baeldung.pattern.hexagonal.service;
+
+import com.baeldung.pattern.hexagonal.repository.WeatherRepository;
+
+public class WeatherForecasterService {
+    private final WeatherRepository repository;
+
+    public WeatherForecasterService(WeatherRepository repository) {
+        this.repository = repository;
+    }
+
+    public double forecast(String location) {
+        String normalizedLocation = getNormalizedLocation(location);
+        return repository.getTemperature(normalizedLocation);
+    }
+
+    private String getNormalizedLocation(String location) {
+        return location == null ? "" : location.toLowerCase();
+    }
+}

patterns/hexagonal/src/main/java/com/baeldung/pattern/hexagonal/ui/WeatherForecasterConsoleUI.java

@@ -0,0 +1,48 @@
+package com.baeldung.pattern.hexagonal.ui;
+
+import com.baeldung.pattern.hexagonal.service.WeatherForecasterService;
+
+import java.io.PrintStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Scanner;
+
+public class WeatherForecasterConsoleUI implements WeatherForecasterUI {
+    private WeatherForecasterService service;
+    private Scanner in;
+    private PrintStream out;
+
+    public WeatherForecasterConsoleUI(WeatherForecasterService service) {
+        this.service = service;
+        this.in = new Scanner(System.in);
+        this.out = new PrintStream(System.out, true, StandardCharsets.UTF_8);
+    }
+
+    @Override
+    public void start() {
+        String input = getInput();
+        while (isNotExit(input)) {
+            showTemperature(input);
+            input = getInput();
+        }
+        stop();
+    }
+
+    private String getInput() {
+        out.print("Location: ");
+        return in.nextLine();
+    }
+
+    private boolean isNotExit(String input) {
+        return !input.equalsIgnoreCase("exit");
+    }
+
+    private void showTemperature(String input) {
+        double temperature = service.forecast(input);
+        out.printf("%.2f\u00B0C%n", temperature);
+    }
+
+    private void stop() {
+        in.close();
+        out.close();
+    }
+}

patterns/hexagonal/src/main/java/com/baeldung/pattern/hexagonal/ui/WeatherForecasterUI.java

@@ -0,0 +1,5 @@
+package com.baeldung.pattern.hexagonal.ui;
+
+public interface WeatherForecasterUI {
+    void start();
+}

patterns/pom.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <artifactId>patterns</artifactId>
@@ -22,6 +22,7 @@
         <module>cqrs-es</module>
         <module>front-controller</module>
         <module>hexagonal-architecture</module>
+        <module>hexagonal</module>
         <module>intercepting-filter</module>
         <module>solid</module>
         <module>clean-architecture</module>