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welcome to section two playing with

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actors in the previous section we

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introduced the actor model and some

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important terminologies to get ourselves

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started we ended the section by creating

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a hello world app in this section we

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will take a look at the actor system and

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hierarchical structure for actors next

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we'll delve into the actor component and

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actor lifecycle we then move on to actor

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definition and creation with props I

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know we created greeter actor in the

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previous section but in this section we

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will go deeper into the act of creation

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and recommended best practices then we

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will talk to actors finally we'll

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discuss supervision and monitoring

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let's start our first video actor system

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and hierarchical structure in this video

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we will take a look at the actor system

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and hierarchical structure for actors

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defining the actor system and finally

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end with the actor system component

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let's get rolling then the actor is an

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object that encapsulates the state and

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behavior the actors communicate by

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exchanging messages you can think about

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the actor is a person in the previous

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section in the first video itself we

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considered you and your friend is an

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example from real life in this video we

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have another example from our life to

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express the hierarchical structure of

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actors like in a software team actors

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naturally form hierarchies let's express

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our life in our team the project manager

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receives requirements from the project

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owner or a client he applies some

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processes on it and distributes it over

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the development teams every team leader

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takes the requirements and splits it

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into smaller tasks and distributes them

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over to his entire team every member in

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the team takes up a task and completes

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it according to his responsibilities and

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when he finishes it he reports it to his

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leader he gives the status as per

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whatever he has completed or hasn't

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completed because of some issues in

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other words every team member needs to

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complete a particular task maybe do it

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himself or split it into smaller tasks

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distribute them over to his team and

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managers team to complete it let's

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Express the situation in the actor world

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one actor which is to oversee a certain

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function in the program might want to

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split up its tasks into smaller more

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manageable pieces for this purpose it

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starts child actors which it supervises

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and if one actor does not have the means

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for dealing with a certain situation it

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sends a corresponding failure message to

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its supervisor asking for help now for

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the question of the hour

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what's the actor system the actor system

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is our route of the actors structure the

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actor system as a collaborating failure

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ensemble of actors is the natural unit

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for managing shed pasilla

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tee's such as scheduling services

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configuration and logging now let's take

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an overview of the actor system

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components the dead-letter office is an

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actor structurally no different from any

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other actor anytime a message is

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destined for an actor that either

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doesn't exist

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or is not running it goes to the

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dead-letter office the user guardian

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actor is the parent of all actors we

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create from the actor system for

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internal actors that Acker creates to

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assist you there is a system Guardian

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actor it serves the same purpose as the

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user guardian actor but for system

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actors the scheduler is a part of the

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actor system responsible for scheduling

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things that may arise in the future the

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event stream is the main event bus of

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each actor system it is used to carry

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log messages and dead letters you can

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also use it to publish messages across

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your entire actor system akka uses a new

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configuration system that's useful for

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configuring akka and your application

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you can access it from the actor system

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the part of the actor system with which

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we've interacted mostly has been the

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user guardian the user guardian is the

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parent for the actors we create from

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actor system which watches and takes

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care of them to summarize the concepts

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of this video we have talked about actor

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system its components and the

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hierarchical structure for actors