Can AKKA be used where processing of events in order is important -

my project requires processing of incoming events in order received , no out of sequence happens.

is use case addressed akka.

messages events processed or pushed actor in order received in mailbox. see discussion: message ordering

actor a1 sends messages m1, m2, m3 a2

actor a3 sends messages m4, m5, m6 a2

this means that:

• m1 delivered must delivered before m2 , m3
• if m2 delivered must delivered before m3
• if m4 delivered must delivered before m5 , m6
• if m5 delivered must delivered before m6
• a2 can see messages a1 interleaved messages a3
• since there no guaranteed delivery, of messages may dropped, i.e. not arrive @ a2

it's possible use stash trait allow message m2 processed when m1 has been processed independently of order sent actor. insuring processing order. see more stash. example below written in scala.

class myactor extends actor stash {      override def receive: receive = receivem1      def receivem1: receive = {         case m1 =>              // staff m1             unstashall()             context become receivem2         case _ =>              stash()      }      def receivem2: receive = {         case m2 =>              // staff m2     } }