🏗️ refactor(architecture): move events from write slices packages to dedicated one for between slices contracts (#20)

Change caused by LinkedIn discussion:

https://www.linkedin.com/feed/update/urn:li:activity:7295062961356771328?commentUrn=urn%3Ali%3Acomment%3A%28activity%3A7295062961356771328%2C7295089102633263104%29&dashCommentUrn=urn%3Ali%3Afsd_comment%3A%287295089102633263104%2Curn%3Ali%3Aactivity%3A7295062961356771328%29

I've given it more thought recently, and indeed events extracted from
slices can be more flexible (to do not couple them to their sourced
command slice, but treat as API between slices).

Especially in cases where the same event can be triggered by two
different commands (although this doesn't happen very frequently).
I have a case in the project, where I think I should refactor handling
the `RecruitCreature`. It should result in two events
`CreatureRecruited` and `AvailableCreaturesChanged` instead of just the
first one. Then in event handlers to reduce available creatures, I will
just handle `AvailableCreaturesChanged` instead of both.

What I would potentially modify is to extract the events separately, as
a contract (system backbone) between slices, while keeping the rest as
it was. The Aggregate and Commands would stay in the write package, as
they're only shared between write slices. Rest API, external consumers
and commands will be also in the same package, do not spread one slice
through "layers" like "domain/application".

Of course, everything I mean in the scope of a single Bounded Context.

Author: MateuszNaKodach

README.md

@@ -94,12 +94,12 @@ Aggregates:
 
 The project follows a Screaming Architecture pattern organized around vertical slices that mirror Event Modeling concepts.
 
-![ScreamingArchitecture](docs/images/ScreamingArchitecture.png)
+![ScreamingArchitecture](docs/images/ScreamingArchitectureEvents.png)
 
 The package structure screams the capabilities of the system by making explicit: commands available to users, events that capture what happened, queries for retrieving information, business rules, and system automations.
 This architecture makes it immediately obvious what the system can do, what rules govern those actions, and how different parts of the system interact through events.
 
-Each module is structured into three distinct types of slices:
+Each module is structured into three distinct types of slices (packages `write`, `read`, `automation`) and there are events (package `events`) between them, which are a system backbone - a contract between all other parts:
 
 ### Write Slices
 Contains commands that represent user intentions, defines business rules through aggregates, produces domain events, and enforces invariants (e.g., RecruitCreature command → CreatureRecruited event, with RecruitCreaturesNotExceedAvailableCreatures rule).

docs/images/ScreamingArchitecture.png

@@ -1,4 +1,4 @@
-package com.dddheroes.heroesofddd.armies.write.addcreature;
+package com.dddheroes.heroesofddd.armies.events;
 
 import com.dddheroes.heroesofddd.armies.write.ArmyEvent;
 import com.dddheroes.heroesofddd.shared.Amount;

docs/images/ScreamingArchitectureEvents.png

@@ -1,4 +1,4 @@
-package com.dddheroes.heroesofddd.armies.write.removecreature;
+package com.dddheroes.heroesofddd.armies.events;
 
 import com.dddheroes.heroesofddd.armies.write.ArmyEvent;
 import com.dddheroes.heroesofddd.shared.Amount;

…ite/addcreature/CreatureAddedToArmy.java …d/armies/events/CreatureAddedToArmy.javasrc/main/java/com/dddheroes/heroesofddd/armies/write/addcreature/CreatureAddedToArmy.java renamed to src/main/java/com/dddheroes/heroesofddd/armies/events/CreatureAddedToArmy.java src/main/java/com/dddheroes/heroesofddd/armies/write/addcreature/CreatureAddedToArmy.java renamed to src/main/java/com/dddheroes/heroesofddd/armies/events/CreatureAddedToArmy.java

@@ -1,9 +1,9 @@
 package com.dddheroes.heroesofddd.armies.write;
 
 import com.dddheroes.heroesofddd.armies.write.addcreature.AddCreatureToArmy;
-import com.dddheroes.heroesofddd.armies.write.addcreature.CreatureAddedToArmy;
+import com.dddheroes.heroesofddd.armies.events.CreatureAddedToArmy;
 import com.dddheroes.heroesofddd.armies.write.addcreature.CanHaveMax7CreatureStacksInArmy;
-import com.dddheroes.heroesofddd.armies.write.removecreature.CreatureRemovedFromArmy;
+import com.dddheroes.heroesofddd.armies.events.CreatureRemovedFromArmy;
 import com.dddheroes.heroesofddd.armies.write.removecreature.CanRemoveOnlyPresentCreatures;
 import com.dddheroes.heroesofddd.armies.write.removecreature.RemoveCreatureFromArmy;
 import com.dddheroes.heroesofddd.shared.Amount;

…ovecreature/CreatureRemovedFromArmy.java …mies/events/CreatureRemovedFromArmy.javasrc/main/java/com/dddheroes/heroesofddd/armies/write/removecreature/CreatureRemovedFromArmy.java renamed to src/main/java/com/dddheroes/heroesofddd/armies/events/CreatureRemovedFromArmy.java src/main/java/com/dddheroes/heroesofddd/armies/write/removecreature/CreatureRemovedFromArmy.java renamed to src/main/java/com/dddheroes/heroesofddd/armies/events/CreatureRemovedFromArmy.java

@@ -3,7 +3,7 @@
 
 import com.dddheroes.heroesofddd.astrologers.write.MonthWeek;
 import com.dddheroes.heroesofddd.astrologers.write.proclaimweeksymbol.ProclaimWeekSymbol;
-import com.dddheroes.heroesofddd.calendar.write.startday.DayStarted;
+import com.dddheroes.heroesofddd.calendar.events.DayStarted;
 import com.dddheroes.heroesofddd.shared.GameMetaData;
 import org.axonframework.commandhandling.gateway.CommandGateway;
 import org.axonframework.config.ProcessingGroup;

src/main/java/com/dddheroes/heroesofddd/armies/write/Army.java

@@ -1,7 +1,7 @@
 package com.dddheroes.heroesofddd.astrologers.automation.whenweeksymbolproclaimedthenincreasedwellingavailablecreatures;
 
-import com.dddheroes.heroesofddd.astrologers.write.proclaimweeksymbol.WeekSymbolProclaimed;
-import com.dddheroes.heroesofddd.creaturerecruitment.write.builddwelling.DwellingBuilt;
+import com.dddheroes.heroesofddd.astrologers.events.WeekSymbolProclaimed;
+import com.dddheroes.heroesofddd.creaturerecruitment.events.DwellingBuilt;
 import com.dddheroes.heroesofddd.creaturerecruitment.write.changeavailablecreatures.IncreaseAvailableCreatures;
 import com.dddheroes.heroesofddd.shared.GameMetaData;
 import org.axonframework.commandhandling.gateway.CommandGateway;

src/main/java/com/dddheroes/heroesofddd/astrologers/automation/whenweekstartedthenproclaimweeksymbol/WhenWeekStartedThenProclaimWeekSymbolProcessor.java

@@ -1,4 +1,4 @@
-package com.dddheroes.heroesofddd.astrologers.write.proclaimweeksymbol;
+package com.dddheroes.heroesofddd.astrologers.events;
 
 import com.dddheroes.heroesofddd.astrologers.write.AstrologersEvent;
 import com.dddheroes.heroesofddd.astrologers.write.AstrologersId;

src/main/java/com/dddheroes/heroesofddd/astrologers/automation/whenweeksymbolproclaimedthenincreasedwellingavailablecreatures/WhenWeekSymbolProclaimedThenIncreaseDwellingAvailableCreaturesProcessor.java

@@ -2,7 +2,7 @@
 
 import com.dddheroes.heroesofddd.astrologers.write.proclaimweeksymbol.OnlyOneSymbolPerWeek;
 import com.dddheroes.heroesofddd.astrologers.write.proclaimweeksymbol.ProclaimWeekSymbol;
-import com.dddheroes.heroesofddd.astrologers.write.proclaimweeksymbol.WeekSymbolProclaimed;
+import com.dddheroes.heroesofddd.astrologers.events.WeekSymbolProclaimed;
 import org.axonframework.commandhandling.CommandHandler;
 import org.axonframework.eventsourcing.EventSourcingHandler;
 import org.axonframework.modelling.command.AggregateCreationPolicy;