Extract repository

Author: mostlyobvious

examples/decider/lib/project_management.rb

@@ -1,3 +1,4 @@
 require_relative "../../../shared/lib/project_management"
 require_relative "project_management/handler"
 require_relative "project_management/issue"
+require_relative "project_management/repository"

examples/decider/lib/project_management/handler.rb

@@ -1,29 +1,19 @@
 module ProjectManagement
   class Handler
     def initialize(event_store)
-      @event_store = event_store
       @decider = Issue
+      @repository = Repository.new(event_store)
     end
 
     def call(cmd)
-      state =
-        @event_store
-          .read
-          .stream(stream_name(cmd.id))
-          .reduce(@decider.initial_state(cmd.id)) do |state, event|
-            @decider.evolve(state, event)
-          end
+      state = @repository.load(cmd.id, @decider)
 
       case result = @decider.decide(cmd, state)
       when StandardError
         raise Error
       else
-        @event_store.append(result, stream_name: stream_name(cmd.id))
+        @repository.store(cmd.id, result)
       end
     end
-
-    private
-
-    def stream_name(id) = "Issue$#{id}"
   end
 end

examples/decider/lib/project_management/repository.rb

@@ -0,0 +1,24 @@
+module ProjectManagement
+  class Repository
+    def initialize(event_store)
+      @event_store = event_store
+    end
+
+    def load(id, decider)
+      @event_store
+        .read
+        .stream(stream_name(id))
+        .reduce(decider.initial_state(id)) do |state, event|
+          decider.evolve(state, event)
+        end
+    end
+
+    def store(id, events)
+      @event_store.append(events, stream_name: stream_name(id))
+    end
+
+    private
+
+    def stream_name(id) = "Issue$#{id}"
+  end
+end