c# barcode generator library open source Protocol Handler in Font

Making Data Matrix ECC200 in Font Protocol Handler

Protocol Handler
Create DataMatrix In None
Using Barcode creator for Font Control to generate, create ECC200 image in Font applications.
www.OnBarcode.com
Printing Code 39 In None
Using Barcode generation for Font Control to generate, create Code 3 of 9 image in Font applications.
www.OnBarcode.com
We ve been writing the react part of the Actor as a pattern to match. In 5, we explored pattern matching. One of the things we learned is that Scala turns patterns into partial functions. Unsurprisingly, the react method takes a PartialFunction as a parameter. Because PartialFunctions are instances, we can do anything with them that we can with other instances. PartialFunctions can also be composed, smooshed together. This means that we can dynamically compose the PartialFunction that we re going to pass to
Encode Barcode In None
Using Barcode drawer for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
UCC - 12 Maker In None
Using Barcode printer for Font Control to generate, create UPCA image in Font applications.
www.OnBarcode.com
CHAPTER 6 ACTORS AND CONCURRENCY
Printing Barcode In None
Using Barcode encoder for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Data Matrix Maker In None
Using Barcode encoder for Font Control to generate, create Data Matrix ECC200 image in Font applications.
www.OnBarcode.com
the react method. This gives us the ability to build an OOP hierarchy that defines how our Actor is going to react to messages.8 We ll cover the basics in this section and dive in more deeply later in the chapter. The way we ve been writing our react calls, we ve hard-coded the partial function, but that s unnecessary. We can calculate the behavior based on the current state of the Actor. We ll implement a chat server that will not allow listeners until there are at least three chats. Let s look at Listing 6-3 and then dissect it.
Encoding QR-Code In None
Using Barcode creator for Font Control to generate, create QR Code image in Font applications.
www.OnBarcode.com
Print USD - 8 In None
Using Barcode creation for Font Control to generate, create Code 11 image in Font applications.
www.OnBarcode.com
Listing 6-3. Chat Server with Dynamic Message Handling import scala.actors.Actor import Actor._ case case case case object GetMessages class Messages(msg: List[String]) class Remove(who: Actor) class Add(who: Actor)
ECC200 Drawer In VB.NET
Using Barcode encoder for .NET framework Control to generate, create Data Matrix ECC200 image in .NET applications.
www.OnBarcode.com
Drawing DataMatrix In None
Using Barcode encoder for Font Control to generate, create DataMatrix image in Font applications.
www.OnBarcode.com
object ChatServer3 extends Actor { private var chats: List[String] = Nil private var listeners: List[Actor] = Nil def act = loop { react(calcReact) } private def calcReact = { val handle: PartialFunction[Any, Unit] = { case s: String => chats = s :: chats notifyListeners() case GetMessages => reply(Messages(chats)) }
Draw ANSI/AIM Code 128 In None
Using Barcode printer for Office Excel Control to generate, create Code 128C image in Excel applications.
www.OnBarcode.com
Recognizing Barcode In VS .NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
8. For those at home who are keeping score, Scheme, an early functional language, led to the asynchronous message-passing model and Actors. The Actor model was adopted by Alan Kay when he designed Smalltalk, the mother of all OOP languages. The Actor model was adopted by Joe Armstrong when he designed Erlang. The Scala team adopted Erlang s Actor model into Scala, which is a hybrid OOP/FP language. Using Scala s unique partial-function composing, we are able to build an inheritance mechanism on top of the Actors. Yes, what was, will be again, or there ain t nothin new under the sun.
UPC Symbol Maker In Objective-C
Using Barcode generator for iPad Control to generate, create UPC Code image in iPad applications.
www.OnBarcode.com
UPC A Maker In None
Using Barcode printer for Office Word Control to generate, create UPC Code image in Microsoft Word applications.
www.OnBarcode.com
CHAPTER 6 ACTORS AND CONCURRENCY
QR Code Creation In .NET
Using Barcode generation for ASP.NET Control to generate, create QR-Code image in ASP.NET applications.
www.OnBarcode.com
Print Code128 In Visual Studio .NET
Using Barcode drawer for Visual Studio .NET Control to generate, create Code 128 image in .NET framework applications.
www.OnBarcode.com
val mgt: PartialFunction[Any, Unit] = if (chats.length < 3) Map.empty else { case Add(who) => listeners = who :: listeners who ! Messages(chats) case Remove(who) => listeners -= who } handle orElse mgt } private def notifyListeners() { listeners.foreach(a => a ! Messages(chats)) } this.start() }
Read Code 128 Code Set A In VB.NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Creating Code 128 In Objective-C
Using Barcode maker for iPhone Control to generate, create Code 128A image in iPhone applications.
www.OnBarcode.com
First we define the messages that the ChatServer3 will accept or send:
Encode PDF-417 2d Barcode In None
Using Barcode encoder for Office Word Control to generate, create PDF417 image in Word applications.
www.OnBarcode.com
Code 39 Full ASCII Encoder In Java
Using Barcode encoder for BIRT reports Control to generate, create ANSI/AIM Code 39 image in BIRT applications.
www.OnBarcode.com
case case case case object GetMessages class Messages(msg: List[String]) class Remove(who: Actor) class Add(who: Actor)
And we define the chat server object:
object ChatServer3 extends Actor { private var chats: List[String] = Nil private var listeners: List[Actor] = Nil
Instead of defining the parameter to react, we ll call the calcReact method:
def act = loop { react(calcReact) }
The calcReact method comprises two partial functions. The first, handle, is static. It is the same no matter what is the state of the Actor.
CHAPTER 6 ACTORS AND CONCURRENCY
private def calcReact = { val handle: PartialFunction[Any, Unit] = { case s: String => chats = s :: chats notifyListeners() case GetMessages => reply(Messages(chats)) }
The second, mgt, is empty if the number of chats is less than three. However, if the number of chats is greater than or equal to three, we allow listeners to register and deregister themselves.
val mgt: PartialFunction[Any, Unit] = if (chats.length < 3) Map.empty else { case Add(who) => listeners = who :: listeners who ! Messages(chats) case Remove(who) => listeners -= who }
Finally, we compose the two partial functions.
handle orElse mgt }
We notify the listeners:
private def notifyListeners() { listeners.foreach(a => a ! Messages(chats)) }
And we don t forget to start the Actor:
this.start }
This is an example of changing the behavior of the Actor on a message-by-message basis. The mechanism of composing the partial function for react based on the current state can be generalized into a protocol handler that accepts and processes messages based on the current Actor state. Next, let s turn our attention to implementing transactions using Actors.
Copyright © OnBarcode.com . All rights reserved.