Sommaire

1. Introduction: Evolving software
2. Clean architecture concepts
3. Spring Modulith : Isolate / Decouple
4. Spring Modulith : Verify
5. Spring Modulith : Test
6. Spring Modulith : Document
7. Spring Modulith: Misc features
8. References

Software delivery challenge

Clean archirecture concepts

• Cohesion: Cohesion refers to the degree to which the elements within a module, class, or component of a software
  system work together to perform a single, well-defined task.

• Coupling: Coupling refers to the degree of interdependence between software modules, classes, or components.
  It measures how much one module relies on another to function correctly.

Spring Modulith: Isolate / Decouple

• Demo Time :

Spring Modulith: Isolate / Decouple

• Leverages Spring's Own Application Event Publisher

• Provides Event persistence (JPA, JDBC, others)

• Provides Externalization abstraction (JMS, AMQP, Kafka)

• Opens the architecture to other useful patterns (outbox pattern, CQRS, audit ...)

Spring Modulith: Verify

• Demo Time :

Spring Modulith: Verify

Verification Includes:

• No cycles on the application module level - the dependencies between modules have to form directed, acyclic graph
• Efferent module access via API packages only - references to types that reside in application module internal packages
  are rejected. configurable
• Explicitly allowed application module dependencies only (optional) - An application module can optionally define
  allowed dependencies via @ApplicationModule(allowedDependencies = …)

Spring Modulith: Test

• Demo Time :

Spring Modulith: Test

• Provides abstractions to bootstrap individual application modules
• Provides abstraction to perform integration test scenarios

// Custom annotation that bootstraps only required module(s)
@ApplicationModuleTest
class SomeApplicationModuleTest {

  @Test
  public void someModuleIntegrationTest(Scenario scenario) {
    // Use the Scenario API to define your integration test
  }
}

@Test
void testName(Scenario scenario) {
  // Start with an event publication
  scenario.publish(new MyApplicationEvent(…)).…

  // Start with a bean invocation
  scenario.stimulate(() -> someBean.someMethod(…)).…

  // Verification
  // Executes the scenario
  ….toArrive(…)

  // Execute and define assertions on the event received
  ….toArriveAndVerify(event -> …)

  ...andWaitForStateChange(() -> someBean.someMethod(…)))
  .andVerify(result -> …);
}

Spring Modulith: Document

• Demo Time :

Spring Modulith: There is more

• Observability integration
• Actuator endpoints