Refactoring (#47)

.docs/ADRs/ADR003-MetaRecordToClass.md

@@ -0,0 +1,3 @@
+# CommandMeta and EventMeta are classes not records
+
+https://stackoverflow.com/questions/73424610/optionalt-as-a-record-parameter-in-java

core/pom.xml

@@ -6,11 +6,11 @@
     <parent>
         <groupId>io.memoria</groupId>
         <artifactId>atom</artifactId>
-        <version>21.34.0</version>
+        <version>21.35.0</version>
     </parent>
     <groupId>io.memoria.atom</groupId>
     <artifactId>core</artifactId>
-    <version>21.34.0</version>
+    <version>21.35.0</version>
     <packaging>jar</packaging>
     <name>${project.groupId}.${project.artifactId}</name>
     <description>Core Module</description>

eventsourcing/pom.xml

@@ -6,12 +6,12 @@
     <parent>
         <groupId>io.memoria</groupId>
         <artifactId>atom</artifactId>
-        <version>21.34.0</version>
+        <version>21.35.0</version>
     </parent>
 
     <groupId>io.memoria.atom</groupId>
     <artifactId>eventsourcing</artifactId>
-    <version>21.34.0</version>
+    <version>21.35.0</version>
     <packaging>jar</packaging>
 
     <name>${project.groupId}.${project.artifactId}</name>
@@ -22,7 +22,7 @@
         <!-- Modules Dependencies -->
         <!--======================================================================================== -->
         <dependency>
-            <groupId>io.memoria.atom</groupId>
+            <groupId>${project.groupId}</groupId>
             <artifactId>core</artifactId>
             <version>${project.parent.version}</version>
         </dependency>

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/aggregate/Decider.java

@@ -21,7 +21,7 @@ public interface Decider {
    * @param eventMeta the new EventMeta
    * @return a new Event with eventMeta as its value
    */
-  Event createBy(Command command, EventMeta eventMeta);
+  Event decide(Command command, EventMeta eventMeta) throws CommandException;
 
   /**
    * @param state     the initial state
@@ -33,11 +33,11 @@ public interface Decider {
    */
   Event decide(State state, Command command, EventMeta eventMeta) throws CommandException;
 
-  default Event apply(Command command) {
-    return createBy(command, eventMeta(command));
+  default Event decide(Command command) throws CommandException {
+    return decide(command, eventMeta(command));
   }
 
-  default Event apply(State state, Command command) throws CommandException {
+  default Event decide(State state, Command command) throws CommandException {
     return decide(state, command, eventMeta(state, command));
   }
 

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/aggregate/DefaultAggregate.java

@@ -53,9 +53,9 @@ public Optional<Event> handle(Command command) throws CommandException {
     Event event;
     if (stateRef.get() == null) {
       eventRepo.fetch(stateId()).forEach(this::evolve);
-      event = decider.apply(command);
+      event = decider.decide(command);
     } else {
-      event = decider.apply(stateRef.get(), command);
+      event = decider.decide(stateRef.get(), command);
     }
     eventRepo.append(event);
     command.meta().sagaSource().ifPresent(sagaSources::add);
@@ -67,9 +67,9 @@ void evolve(Event event) {
     State currentState = stateRef.get();
     State newState;
     if (isInitializerEvent(event)) {
-      newState = evolver.apply(event);
+      newState = evolver.evolve(event);
     } else {
-      newState = evolver.apply(currentState, event);
+      newState = evolver.evolve(currentState, event);
     }
     stateRef.set(newState);
     processedCommands.add(event.meta().commandId());

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/aggregate/Evolver.java

@@ -1,7 +1,7 @@
 package io.memoria.atom.eventsourcing.aggregate;
 
 import io.memoria.atom.eventsourcing.event.Event;
-import io.memoria.atom.eventsourcing.event.exceptions.InvalidEvolutionEvent;
+import io.memoria.atom.eventsourcing.event.exceptions.InvalidEvent;
 import io.memoria.atom.eventsourcing.state.State;
 import io.memoria.atom.eventsourcing.state.StateMeta;
 
@@ -12,7 +12,7 @@ public interface Evolver {
    * @param stateMeta the new State stateMeta
    * @return a new State with stateMeta as its meta value
    */
-  State createBy(Event event, StateMeta stateMeta);
+  State evolve(Event event, StateMeta stateMeta);
 
   /**
    * @param state     initial State
@@ -22,11 +22,11 @@ public interface Evolver {
    */
   State evolve(State state, Event event, StateMeta stateMeta);
 
-  default State apply(Event e) {
-    return createBy(e, stateMeta(e));
+  default State evolve(Event e) {
+    return evolve(e, stateMeta(e));
   }
 
-  default State apply(State state, Event event) {
+  default State evolve(State state, Event event) {
     return evolve(state, event, stateMeta(state, event));
   }
 
@@ -36,7 +36,7 @@ default StateMeta stateMeta(Event e) {
 
   default StateMeta stateMeta(State s, Event e) {
     if (s.version() + 1 != e.version()) {
-      throw InvalidEvolutionEvent.of(s, e);
+      throw InvalidEvent.ofEvolution(s, e);
     }
     return s.meta().incrementVersion();
   }

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/command/CommandMeta.java

@@ -10,7 +10,7 @@
 import java.util.Objects;
 import java.util.Optional;
 
-public final class CommandMeta implements Partitioned, Serializable {
+public class CommandMeta implements Partitioned, Serializable {
   @Serial
   private static final long serialVersionUID = 0L;
   private final CommandId commandId;
@@ -67,19 +67,7 @@ public int hashCode() {
 
   @Override
   public String toString() {
-    return "CommandMeta["
-           + "commandId="
-           + commandId
-           + ", "
-           + "stateId="
-           + stateId
-           + ", "
-           + "timestamp="
-           + timestamp
-           + ", "
-           + "sagaSource="
-           + sagaSource
-           + ']';
+    return STR."CommandMeta[commandId=\{commandId}, stateId=\{stateId}, timestamp=\{timestamp}, sagaSource=\{sagaSource}\{']'}";
   }
 }
 

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/command/exceptions/CommandRuntimeException.java → eventsourcing/src/main/java/io/memoria/atom/eventsourcing/command/exceptions/CommandRTE.java

@@ -2,10 +2,10 @@
 
 import io.memoria.atom.eventsourcing.command.Command;
 
-public class CommandRuntimeException extends RuntimeException {
+public class CommandRTE extends RuntimeException {
   private final Command command;
 
-  protected CommandRuntimeException(String msg, Command command) {
+  protected CommandRTE(String msg, Command command) {
     super(msg);
     this.command = command;
   }

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/command/exceptions/InvalidEvolutionCommand.java → eventsourcing/src/main/java/io/memoria/atom/eventsourcing/command/exceptions/InvalidCommand.java

@@ -3,16 +3,21 @@
 import io.memoria.atom.eventsourcing.command.Command;
 import io.memoria.atom.eventsourcing.state.State;
 
-public class InvalidEvolutionCommand extends CommandException {
-  protected InvalidEvolutionCommand(String msg, Command command) {
+public class InvalidCommand extends CommandException {
+  protected InvalidCommand(String msg, Command command) {
     super(msg, command);
   }
 
-  public static InvalidEvolutionCommand of(State state, Command command) {
+  public static InvalidCommand ofCreation(Command command) {
+    var msg = "Invalid creation command: %s[%s]".formatted(command.getClass().getSimpleName(), command.meta());
+    return new InvalidCommand(msg, command);
+  }
+
+  public static InvalidCommand ofEvolution(State state, Command command) {
     var msg = "Invalid evolution command: %s[%s] to the state: %s[%s]".formatted(command.getClass().getSimpleName(),
                                                                                  command.meta(),
                                                                                  state.getClass().getSimpleName(),
                                                                                  state.meta());
-    return new InvalidEvolutionCommand(msg, command);
+    return new InvalidCommand(msg, command);
   }
 }

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/command/exceptions/MismatchingCommandState.java

@@ -3,7 +3,7 @@
 import io.memoria.atom.eventsourcing.command.Command;
 import io.memoria.atom.eventsourcing.state.StateId;
 
-public class MismatchingCommandState extends CommandRuntimeException {
+public class MismatchingCommandState extends CommandRTE {
   protected MismatchingCommandState(String msg, Command command) {
     super(msg, command);
   }

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/command/exceptions/UnknownCommandRTE.java

@@ -0,0 +1,19 @@
+package io.memoria.atom.eventsourcing.command.exceptions;
+
+import io.memoria.atom.eventsourcing.command.Command;
+
+public class UnknownCommandRTE extends CommandRTE {
+  private static final String MESSAGE = "Unknown Command: %s[%s] implementation";
+
+  protected UnknownCommandRTE(Command command) {
+    this(MESSAGE.formatted(command.getClass().getSimpleName(), command.meta()), command);
+  }
+
+  protected UnknownCommandRTE(String message, Command command) {
+    super(message, command);
+  }
+
+  public static UnknownCommandRTE of(Command command) {
+    return new UnknownCommandRTE(command);
+  }
+}

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/event/EventMeta.java

@@ -11,7 +11,7 @@
 import java.util.Objects;
 import java.util.Optional;
 
-public final class EventMeta implements Partitioned, Versioned, Serializable {
+public class EventMeta implements Partitioned, Versioned, Serializable {
   @Serial
   private static final long serialVersionUID = 0L;
   private final EventId eventId;
@@ -87,26 +87,7 @@ public int hashCode() {
 
   @Override
   public String toString() {
-    return "EventMeta["
-           + "eventId="
-           + eventId
-           + ", "
-           + "version="
-           + version
-           + ", "
-           + "stateId="
-           + stateId
-           + ", "
-           + "commandId="
-           + commandId
-           + ", "
-           + "timestamp="
-           + timestamp
-           + ", "
-           + "sagaSource="
-           + sagaSource
-           + ']';
+    return STR."EventMeta[eventId=\{eventId}, version=\{version}, stateId=\{stateId}, commandId=\{commandId}, timestamp=\{timestamp}, sagaSource=\{sagaSource}\{']'}";
   }
-
 }
 

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/event/exceptions/EventRuntimeException.java → eventsourcing/src/main/java/io/memoria/atom/eventsourcing/event/exceptions/EventRTE.java

@@ -2,10 +2,10 @@
 
 import io.memoria.atom.eventsourcing.event.Event;
 
-public class EventRuntimeException extends RuntimeException {
+public class EventRTE extends RuntimeException {
   private final Event event;
 
-  protected EventRuntimeException(String msg, Event event) {
+  protected EventRTE(String msg, Event event) {
     super(msg);
     this.event = event;
   }

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/event/exceptions/InvalidEvolutionEvent.java → eventsourcing/src/main/java/io/memoria/atom/eventsourcing/event/exceptions/InvalidEvent.java

@@ -3,16 +3,21 @@
 import io.memoria.atom.eventsourcing.event.Event;
 import io.memoria.atom.eventsourcing.state.State;
 
-public class InvalidEvolutionEvent extends EventRuntimeException {
-  protected InvalidEvolutionEvent(String msg, Event event) {
+public class InvalidEvent extends EventRTE {
+  protected InvalidEvent(String msg, Event event) {
     super(msg, event);
   }
 
-  public static InvalidEvolutionEvent of(State state, Event event) {
+  public static InvalidEvent ofCreation(Event event) {
+    var msg = "Invalid creation event: %s[%s]".formatted(event.getClass().getSimpleName(), event.meta());
+    return new InvalidEvent(msg, event);
+  }
+
+  public static InvalidEvent ofEvolution(State state, Event event) {
     var msg = "Invalid evolution event: %s[%s] to the state: %s[%s]".formatted(event.getClass().getSimpleName(),
                                                                                event.meta(),
                                                                                state.getClass().getSimpleName(),
                                                                                state.meta());
-    return new InvalidEvolutionEvent(msg, event);
+    return new InvalidEvent(msg, event);
   }
 }

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/event/exceptions/MismatchingEvent.java

@@ -3,7 +3,7 @@
 import io.memoria.atom.eventsourcing.event.Event;
 import io.memoria.atom.eventsourcing.state.StateId;
 
-public class MismatchingEvent extends EventRuntimeException {
+public class MismatchingEvent extends EventRTE {
   protected MismatchingEvent(String msg, Event event) {
     super(msg, event);
   }

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/event/exceptions/UnknownEvent.java

@@ -2,7 +2,7 @@
 
 import io.memoria.atom.eventsourcing.event.Event;
 
-public class UnknownEvent extends EventRuntimeException {
+public class UnknownEvent extends EventRTE {
   private static final String MESSAGE = "Unknown Event: %s[%s] implementation";
 
   protected UnknownEvent(Event event) {

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/saga/Saga.java

@@ -8,15 +8,14 @@
 import io.memoria.atom.eventsourcing.state.StateId;
 
 import java.util.Optional;
-import java.util.function.Function;
 import java.util.function.Supplier;
 
-public interface Saga extends Function<Event, Optional<Command>> {
+public interface Saga {
   Supplier<Id> idSupplier();
 
   Supplier<Long> timeSupplier();
 
-  Optional<Command> apply(Event event);
+  Optional<Command> react(Event event);
 
   default CommandMeta commandMeta(StateId stateId, Event event) {
     return new CommandMeta(CommandId.of(idSupplier().get()), stateId, timeSupplier().get(), event.meta().eventId());

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/saga/SagaHandler.java

@@ -15,8 +15,8 @@ public SagaHandler(Saga saga, CommandPublisher commandPublisher) {
     this.commandPublisher = commandPublisher;
   }
 
-  public Optional<Command> handle(Event event) {
-    Optional<Command> result = saga.apply(event);
+  public Optional<Command> react(Event event) {
+    Optional<Command> result = saga.react(event);
     result.ifPresent(commandPublisher::publish);
     return result;
   }

eventsourcing/src/main/java/io/memoria/atom/eventsourcing/state/State.java

@@ -9,6 +9,8 @@
 public interface State extends Partitioned, Versioned, Serializable {
   StateMeta meta();
 
+  State withMeta(StateMeta meta);
+
   default StateId stateId() {
     return meta().stateId();
   }