restructured into services

Author: ttulka

README.md

@@ -10,18 +10,18 @@ mvn spring-boot:run
 
 ## Table of Contents
 
-- [Domain Services](#domain-services)
+- [Domains](#domains)
   + [Core Domain](#core-domain)
   + [Supporting Subdomains](#supporting-subdomains)
-  + [Services Event Workflow](#services-event-workflow)
+  + [Event Workflow](#event-workflow)
   + [Services Dependencies](#services-dependencies)
 - [Architectural Overview](#architectural-overview)
   + [Screaming Architecture](#screaming-architecture)
   + [Packaging](#packaging)
   + [Assembling](#assembling)
   + [Anatomy of a Service](#anatomy-of-a-service)
 
-## Domain Services
+## Domains
 
 Several [Business Capabilities][vcha] have been identified:
 
@@ -64,25 +64,25 @@ Later, we can think about more supporting domains (not implemented in this proje
   - provide help
   - loyalty program
 
-The e-commerce system is a web application using a **Catalogue** service implementing the [Backends For Frontends (BFF)][bff] pattern.
+The e-commerce system is a web application using a **Portal** component implementing the [Backends For Frontends (BFF)][bff] pattern.
 
 [bff]: https://samnewman.io/patterns/architectural/bff/
 
-### Services Event Workflow
+### Event Workflow
 
-The communication among services is implemented via events:
+The communication among domains is implemented via events:
 
-![Service Event Workflow](doc/services-event-workflow.png)
+![Event Workflow](doc/event-workflow.png)
 
 When the customer places an order the following process starts up (the happy path):
 
-1. Shipping service prepares a new delivery.
-1. Sales service creates a new order and publishes the `OrderPlaced` event.
-1. Shipping service accepts the delivery.
-1. Billing service collects payment for the order and publishes the `PaymentCollected` event.
-1. Warehouse service fetches goods from the stock and publishes the `GoodsFetched` event.
-1. Shipping service dispatches the delivery and publishes the `DeliveryDispatched` event.
-1. Warehouse service updates the stock.
+1. Shipping prepares a new delivery.
+1. Sales creates a new order and publishes the `OrderPlaced` event.
+1. Shipping accepts the delivery.
+1. Billing collects payment for the order and publishes the `PaymentCollected` event.
+1. Warehouse fetches goods from the stock and publishes the `GoodsFetched` event.
+1. Shipping dispatches the delivery and publishes the `DeliveryDispatched` event.
+1. Warehouse updates the stock.
 
 There is only the basic "happy path" workflow implemented with a big room for improvement, for example when Shipping doesn't get bot Events within a time period, the delivery process should be cancelled etc.. 
 
@@ -96,7 +96,7 @@ The actual dependencies come only from Listeners which fulfill the role of the A
 
 Events contain no Domain Objects. 
 
-For communication across Services an Event Publisher abstraction is used, located in the package `..ecommerce.common`. The interface is an Output Port (in the Hexagonal Architecture) and as a cross-cutting concern is its implementation injected by the Application.  
+For communication across Services an Event Publisher abstraction is used, located in the package `..ecommerce.common.events`. The interface is an Output Port (in the Hexagonal Architecture) and as a cross-cutting concern is its implementation injected by the Application.  
 
 ## Architectural Overview
 
@@ -146,7 +146,7 @@ As shown in the previous section, the code is structured by the domain together
 
 Such a packaging style is the first step for a further modularization. 
 
-The semantic of a package is following: `company.product.domain.aggregate.impl`, where `aggregate` and `impl` are optional. Full example: `com.ttulka.ecommerce.billing.payment.jdbc`. 
+The semantic of a package is following: `company.product.domain.service.[entity|impl]`, where `entity` and `impl` are optional. Full example: `com.ttulka.ecommerce.billing.payment.jdbc`. 
 
 ### Assembling
 
@@ -155,63 +155,67 @@ To show that the Monolith architectural pattern is not equal to the Big Ball Of
 The services can be further cut into separate modules (eg. Maven artifacts) by feature:
 ```
 com.ttulka.ecommerce:ecommerce-application
-com.ttulka.ecommerce:billing-service
-com.ttulka.ecommerce:sales-service
-com.ttulka.ecommerce:shipping-service
-com.ttulka.ecommerce:warehouse-service
+com.ttulka.ecommerce.sales:catalog-service
+com.ttulka.ecommerce.sales:cart-service
+com.ttulka.ecommerce.sales:order-service
+com.ttulka.ecommerce.billing:payment-service
+com.ttulka.ecommerce.shipping:delivery-service
+com.ttulka.ecommerce.warehouse:warehouse-service
 ```
 
 Or by [component](https://blog.ttulka.com/package-by-component-with-clean-modules-in-java):
 ```
-com.ttulka.ecommerce:billing-domain
-com.ttulka.ecommerce:billing-jdbc
-com.ttulka.ecommerce:billing-rest
-com.ttulka.ecommerce:billing-events
-com.ttulka.ecommerce:billing-listeners
+com.ttulka.ecommerce.billing:payment-domain
+com.ttulka.ecommerce.billing:payment-jdbc
+com.ttulka.ecommerce.billing:payment-rest
+com.ttulka.ecommerce.billing:payment-events
+com.ttulka.ecommerce.billing:payment-listeners
 ```
 
 In detail:
 ```
-com.ttulka.ecommerce:billing-domain
+com.ttulka.ecommerce.billing:payment-domain
     ..billing
         payment
             Payment
             PaymentId
-            ReferenceId
-            Money
-        CollectPayment
-        FindPayments
-com.ttulka.ecommerce:billing-jdbc
+            CollectPayment
+            FindPayments
+com.ttulka.ecommerce.billing:payment-jdbc
     ..billing.payment.jdbc
         PaymentJdbc
-        PaymentsJdbc        
-com.ttulka.ecommerce:billing-rest
-    ..billing.rest
+        CollectPaymentJdbc   
+        FindPaymentsJdbc     
+com.ttulka.ecommerce.billing:payment-rest
+    ..billing.payment.rest
         PaymentController
-com.ttulka.ecommerce:billing-events
-    ..billing
+com.ttulka.ecommerce.billing:payment-events
+    ..billing.payment
         PaymentCollected
-com.ttulka.ecommerce:billing-listeners
-    ..billing.listeners
-        OrderPlacedListener        
+com.ttulka.ecommerce.billing:payment-listeners
+    ..billing.payment.listeners
+        OrderPlacedListener
 ```
 
 Which can be brought together with a Spring Boot Starter, containing only Configuration classes and dependencies on other modules:
 ```
-com.ttulka.ecommerce:billing-spring-boot-starter
-    ..billing
-        payment.jdbc
+com.ttulka.ecommerce.billing:payment-spring-boot-starter
+    ..billing.payment
+        jdbc
             PaymentJdbcConfig
         listeners
-            BillingListenersConfig
+            PaymentListenersConfig
     META-INF
         spring.factories
 ```
 
-Note: Events are actually part of the domain, that's why they are in the package `..ecommerce.billing` and not in `..ecommerce.billing.events`. They are in a separate module to break the build cyclic dependencies: a dependent module (Listener) needs to know only Events and not the entire Domain. 
+Note: Events are actually part of the domain, that's why they are in the package `..ecommerce.billing.payment` and not in `..ecommerce.billing.payment.events`. They are in a separate module to break the build cyclic dependencies: a dependent module (Listener) needs to know only Events and not the entire Domain. 
 
 ### Anatomy of a Service 
 
+**[Service](http://udidahan.com/2010/11/15/the-known-unknowns-of-soa/)** is the technical authority for a specific business capability.
+- Single domain can contain multiple services (for example, Sales domain contains Catalog, Cart and Order services).
+
 **Application** is a deployment unit. A monolithic Application can have more Services.
 - Bootstrap (application container etc.). 
 - Cross-cutting concerns (security, transactions, messaging, logging, etc.).

doc/services-event-workflow.png doc/event-workflow.png

@@ -1,7 +1,6 @@
-package com.ttulka.ecommerce.billing;
+package com.ttulka.ecommerce.billing.payment;
 
-import com.ttulka.ecommerce.billing.payment.ReferenceId;
-import com.ttulka.ecommerce.common.money.Money;
+import com.ttulka.ecommerce.common.primitives.Money;
 
 /**
  * Collect Payment use-case.

doc/service-anatomy-example.png

@@ -1,6 +1,4 @@
-package com.ttulka.ecommerce.billing;
-
-import com.ttulka.ecommerce.billing.payment.Payments;
+package com.ttulka.ecommerce.billing.payment;
 
 /**
  * Find Payments use-case.

src/main/java/com/ttulka/ecommerce/billing/CollectPayment.java src/main/java/com/ttulka/ecommerce/billing/payment/CollectPayment.java

@@ -1,6 +1,6 @@
 package com.ttulka.ecommerce.billing.payment;
 
-import com.ttulka.ecommerce.common.money.Money;
+import com.ttulka.ecommerce.common.primitives.Money;
 
 /**
  * Payment entity.

src/main/java/com/ttulka/ecommerce/billing/FindPayments.java src/main/java/com/ttulka/ecommerce/billing/payment/FindPayments.java

@@ -1,4 +1,4 @@
-package com.ttulka.ecommerce.billing;
+package com.ttulka.ecommerce.billing.payment;
 
 import java.time.Instant;
 

src/main/java/com/ttulka/ecommerce/billing/payment/Payment.java

@@ -1,10 +1,10 @@
 package com.ttulka.ecommerce.billing.payment.jdbc;
 
-import com.ttulka.ecommerce.billing.CollectPayment;
+import com.ttulka.ecommerce.billing.payment.CollectPayment;
 import com.ttulka.ecommerce.billing.payment.Payment;
 import com.ttulka.ecommerce.billing.payment.ReferenceId;
 import com.ttulka.ecommerce.common.events.EventPublisher;
-import com.ttulka.ecommerce.common.money.Money;
+import com.ttulka.ecommerce.common.primitives.Money;
 
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.transaction.annotation.Propagation;

src/main/java/com/ttulka/ecommerce/billing/PaymentCollected.java src/main/java/com/ttulka/ecommerce/billing/payment/PaymentCollected.java

@@ -1,6 +1,6 @@
 package com.ttulka.ecommerce.billing.payment.jdbc;
 
-import com.ttulka.ecommerce.billing.FindPayments;
+import com.ttulka.ecommerce.billing.payment.FindPayments;
 import com.ttulka.ecommerce.billing.payment.Payments;
 import com.ttulka.ecommerce.common.events.EventPublisher;
 

src/main/java/com/ttulka/ecommerce/billing/payment/jdbc/CollectPaymentJdbc.java

@@ -3,12 +3,12 @@
 import java.time.Instant;
 import java.util.UUID;
 
-import com.ttulka.ecommerce.billing.PaymentCollected;
 import com.ttulka.ecommerce.billing.payment.Payment;
+import com.ttulka.ecommerce.billing.payment.PaymentCollected;
 import com.ttulka.ecommerce.billing.payment.PaymentId;
 import com.ttulka.ecommerce.billing.payment.ReferenceId;
 import com.ttulka.ecommerce.common.events.EventPublisher;
-import com.ttulka.ecommerce.common.money.Money;
+import com.ttulka.ecommerce.common.primitives.Money;
 
 import org.springframework.jdbc.core.JdbcTemplate;
 

src/main/java/com/ttulka/ecommerce/billing/payment/jdbc/FindPaymentsJdbc.java

@@ -7,18 +7,18 @@
 import org.springframework.jdbc.core.JdbcTemplate;
 
 /**
- * Configuration for JDBC implementation for Payment domain.
+ * Configuration for JDBC implementation for Payment service.
  */
 @Configuration
 class PaymentJdbcConfig {
 
     @Bean
-    FindPaymentsJdbc findPayments(JdbcTemplate jdbcTemplate, EventPublisher eventPublisher) {
+    FindPaymentsJdbc findPaymentsJdbc(JdbcTemplate jdbcTemplate, EventPublisher eventPublisher) {
         return new FindPaymentsJdbc(jdbcTemplate, eventPublisher);
     }
 
     @Bean
-    CollectPaymentJdbc collectPayment(JdbcTemplate jdbcTemplate, EventPublisher eventPublisher) {
+    CollectPaymentJdbc collectPaymentJdbc(JdbcTemplate jdbcTemplate, EventPublisher eventPublisher) {
         return new CollectPaymentJdbc(jdbcTemplate, eventPublisher);
     }
 }

src/main/java/com/ttulka/ecommerce/billing/payment/jdbc/PaymentJdbc.java

@@ -11,7 +11,7 @@
 import com.ttulka.ecommerce.billing.payment.Payments;
 import com.ttulka.ecommerce.billing.payment.ReferenceId;
 import com.ttulka.ecommerce.common.events.EventPublisher;
-import com.ttulka.ecommerce.common.money.Money;
+import com.ttulka.ecommerce.common.primitives.Money;
 
 import org.springframework.jdbc.core.JdbcTemplate;
 

src/main/java/com/ttulka/ecommerce/billing/payment/jdbc/PaymentJdbcConfig.java

@@ -1,9 +1,9 @@
-package com.ttulka.ecommerce.billing.listeners;
+package com.ttulka.ecommerce.billing.payment.listeners;
 
-import com.ttulka.ecommerce.billing.CollectPayment;
+import com.ttulka.ecommerce.billing.payment.CollectPayment;
 import com.ttulka.ecommerce.billing.payment.ReferenceId;
-import com.ttulka.ecommerce.common.money.Money;
-import com.ttulka.ecommerce.sales.OrderPlaced;
+import com.ttulka.ecommerce.common.primitives.Money;
+import com.ttulka.ecommerce.sales.order.OrderPlaced;
 
 import org.springframework.scheduling.annotation.Async;
 import org.springframework.transaction.event.TransactionalEventListener;

src/main/java/com/ttulka/ecommerce/billing/payment/jdbc/PaymentsJdbc.java

@@ -1,17 +1,17 @@
-package com.ttulka.ecommerce.billing.listeners;
+package com.ttulka.ecommerce.billing.payment.listeners;
 
-import com.ttulka.ecommerce.billing.CollectPayment;
+import com.ttulka.ecommerce.billing.payment.CollectPayment;
 
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
 /**
- * Configuration for Billing event listeners.
+ * Configuration for Payment event listeners.
  */
 @Configuration
-class BillingListenersConfig {
+class PaymentListenersConfig {
 
-    @Bean("billing-orderPlacedListener") // a custom name to avoid collision
+    @Bean("payment-orderPlacedListener") // a custom name to avoid collision
     OrderPlacedListener orderPlacedListener(CollectPayment collectPayment) {
         return new OrderPlacedListener(collectPayment);
     }

src/main/java/com/ttulka/ecommerce/billing/listeners/OrderPlacedListener.java src/main/java/com/ttulka/ecommerce/billing/payment/listeners/OrderPlacedListener.java

@@ -1,10 +1,10 @@
-package com.ttulka.ecommerce.billing.rest;
+package com.ttulka.ecommerce.billing.payment.rest;
 
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
 
-import com.ttulka.ecommerce.billing.FindPayments;
+import com.ttulka.ecommerce.billing.payment.FindPayments;
 
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;