Touching up the add-points consumer

to really fake implement points-adding method and more cleanly stop
consuming.

sylvilagus/jruby/lib/sylvilagus/ch04/add_points_consumer.rb

@@ -7,9 +7,26 @@ class Sylvilagus::Ch04::AddPointsConsumer
   class Consumer < Java::ComRabbitmqClient::DefaultConsumer
     def handleDelivery(consumer_tag, envelope, properties, body)
       message = Java::OrgJruby::RubyString.bytes_to_string(body)
-      puts "Got me a message! #{message.inspect}"
+
+      if message == 'quit'
+        channel.basic_cancel(consumer_tag)
+        @done = true
+        return
+      end
+
+      add_points_to_user(JSON.parse(message).fetch('user_id'))
 
       channel.basic_ack(envelope.delivery_tag, false)
+    rescue StandardError
+      channel.basic_nack(envelope.delivery_tag, false)
+    end
+
+    def add_points_to_user(user_id)
+      puts "Adding points to user: #{user_id}"
+    end
+
+    def done?
+      !!@done
     end
   end
 
@@ -24,10 +41,12 @@ class Sylvilagus::Ch04::AddPointsConsumer
     channel.queue_declare('add-points', false, true, false, nil)
     channel.queue_bind('add-points', 'upload-pictures', '')
 
+    consumer = Consumer.new(channel)
     puts "Consuming from 'upload-pictures' exchange"
     channel.basic_consume('add-points', false, 'add-points-consumer',
-                          false, false, nil, Consumer.new(channel))
+                          false, false, nil, consumer)
     loop do
+      break if consumer.done?
       sleep 1
     end
     return 0