The set of papers collected in this issue originated from the AGERE! Workshop series - the last edition was held in 2017 - and concern the application of actor-based approaches to mainstream application domains and the discussion of related issues. The issue is divided into two parts. The first part concerns Web Programming; Data-Intensive Parallel Programming; Mobile Computing; Self-Organizing Systems and the second part concerns Scheduling; Debugging; Communication and Coordination; Monitoring.

When it comes to big data processing, we can no longer ignore concurrency or try to add it in after the fact. Fortunately, the solution is not a new paradigm of development, but rather an old one. With this hands-on guide, Java and Scala developers will learn how to embrace concurrent and distributed applications with the open source Akka toolkit. You’ll learn how to put the actor model and its associated patterns to immediate and practical use. Throughout the book, you’ll deal with an analogous workforce problem: how to schedule a group of people across a variety of projects while optimizing their time and skillsets. This example will help you understand how Akka uses actors, streams, and other tools to stitch your application together. Model software that reflects the real world with domain-driven design Learn principles and practices for implementing individual actors Unlock the real potential of Akka with patterns for combining multiple actors Understand the consistency tradeoffs in a distributed system Use several Akka methods for isolating and dealing with failures Explore ways to build systems that support availability and scalability Tune your Akka application for performance with JVM tools and dispatchers

Build fault-tolerant, robust, and distributed applications in Scala Key Features - Understand and use the concepts of reactive programming to build distributed systems running on multiple nodes. - Learn how reactive architecture reduces complexity throughout the development process. - Get to grips with functional reactive programming and Reactive Microservices. Book Description Reactive programming is a scalable, fast way to build applications, and one that helps us write code that is concise, clear, and readable. It can be used for many purposes such as GUIs, robotics, music, and others, and is central to many concurrent systems. This book will be your guide to getting started with Reactive programming in Scala. You will begin with the fundamental concepts of Reactive programming and gradually move on to working with asynchronous data streams. You will then start building an application using Akka Actors and extend it using the Play framework. You will also learn about reactive stream specifications, event sourcing techniques, and different methods to integrate Akka Streams into the Play Framework. This book will also take you one step forward by showing you the advantages of the Lagom framework while working with reactive microservices. You will also learn to scale applications using multi-node clusters and test, secure, and deploy your microservices to the cloud. By the end of the book, you will have gained the knowledge to build robust and distributed systems with Scala and Akka. What you will learn Understand the fundamental principles of Reactive and Functional programming Develop applications utilizing features of the Akka framework Explore techniques to integrate Scala, Akka, and Play together Learn about Reactive Streams with real-time use cases Develop Reactive Web Applications with Play, Scala, Akka, and Akka Streams Develop and deploy Reactive microservices using the Lagom framework and ConductR Who this book is for This book is for Scala developers who would like to build fault-tolerant, scalable distributed systems. No knowledge of Reactive programming is required.

USE THE ACTOR MODEL TO BUILD SIMPLER SYSTEMS WITH BETTER PERFORMANCE AND SCALABILITY Enterprise software development has been much more difficult and failure-prone than it needs to be. Now, veteran software engineer and author Vaughn Vernon offers an easier and more rewarding method to succeeding with Actor model. Reactive Messaging Patterns with the Actor Model shows how the reactive enterprise approach, Actor model, Scala, and Akka can help you overcome previous limits of performance and scalability, and skillfully address even the most challenging non-functional requirements. Reflecting his own cutting-edge work, Vernon shows architects and developers how to translate the longtime promises of Actor model into practical reality. First, he introduces the tenets of reactive software, and shows how the message-driven Actor model addresses all of them–making it possible to build systems that are more responsive, resilient, and elastic. Next, he presents a practical Scala bootstrap tutorial, a thorough introduction to Akka and Akka Cluster, and a full chapter on maximizing performance and scalability with Scala and Akka. Building on this foundation, you’ll learn to apply enterprise application and integration patterns to establish message channels and endpoints; efficiently construct, route, and transform messages; and build robust systems that are simpler and far more successful. Coverage Includes How reactive architecture replaces complexity with simplicity throughout the core, middle, and edges The characteristics of actors and actor systems, and how Akka makes them more powerful Building systems that perform at scale on one or many computing nodes Establishing channel mechanisms, and choosing appropriate channels for each application and integration challenge Constructing messages to clearly convey a sender’s intent in communicating with a receiver Implementing a Process Manager for your Domain-Driven Designs Decoupling a message’s source and destination, and integrating appropriate business logic into its router Understanding the transformations a message may experience in applications and integrations Implementing persistent actors using Event Sourcing and reactive views using CQRS Find unique online training on Domain-Driven Design, Scala, Akka, and other software craftsmanship topics using the for{comprehension} website at forcomprehension.com.

Writing truly concurrent software on the Java Virtual Machine just got a whole lot easier. The Akka Toolkit takes the sting out of coding for multiple cores, multiple processors, and even multiple machines. Akka Concurrency will show you what it means to design and write software in the paradigm of Akka. You'll learn how to think about your software in new and exciting ways that will allow you to express your designs naturally, allowing you to focus on the business of your software more than on the concurrency of it. This book picks up where the Akka documentation leaves off, exploring the how and the why of Akka, in a way that will empower you to grow your applications to new levels of scalability, responsiveness, and performance.

The transition from sequential to parallel computation is an area of critical concern in today's computer technology, particularly in architecture, programming languages, systems, and artificial intelligence. This book addresses central issues in concurrency, and by producing both a syntactic definition and a denotational model of Hewitt's actor paradigm—a model of computation specifically aimed at constructing and analyzing distributed large-scale parallel systems—it substantially advances the understanding of parallel computation. Contents Introduction • General Design Decisions • Computation in ACTOR Systems • A More Expressive Language • A Model for ACTOR Systems • Concurrency Issues • Abstraction and Compositionality • Conclusions

Handle every problem you come across in the world of Clojure programming with this expert collection of recipes About This Book Discover a wide variety of practical cases and real world techniques to enhance your productivity with Clojure. Learn to resolve the everyday issues you face with a functional mindset using Clojure You will learn to write highly efficient, more productive, and error-free programs without the risk of deadlocks and race-conditions Who This Book Is For This book is for Clojure developers who have some Clojure programming experience and are well aware of their shortcomings. If you want to learn to tackle common problems, become an expert, and develop a solid skill set, then this book is for you. What You Will Learn Manipulate, access, filter, and transform your data with Clojure Write efficient parallelized code through Clojure abstractions Tackle Complex Concurrency easily with Reactive Programming Build on Haskell abstractions to write dynamic functional tests Write AWS Lambda functions effortlessly Put Clojure in use into your IoT devices Use Clojure with Slack for instant monitoring Scaling your Clojure application using Docker Develop real-time system interactions using MQTT and websockets In Detail When it comes to learning and using a new language you need an effective guide to be by your side when things get rough. For Clojure developers, these recipes have everything you need to take on everything this language offers. This book is divided into three high impact sections. The first section gives you an introduction to live programming and best practices. We show you how to interact with your connections by manipulating, transforming, and merging collections. You'll learn how to work with macros, protocols, multi-methods, and transducers. We'll also teach you how to work with languages such as Java, and Scala. The next section deals with intermediate-level content and enhances your Clojure skills, here we'll teach you concurrency programming with Clojure for high performance. We will provide you with advanced best practices, tips on Clojure programming, and show you how to work with Clojure while developing applications. In the final section you will learn how to test, deploy and analyze websocket behavior when your app is deployed in the cloud. Finally, we will take you through DevOps. Developing with Clojure has never been easier with these recipes by your side! Style and approach This book takes a recipe-based approach by diving directly into helpful programming concepts. It will give you a foolproof approach to programming and teach you how to deal with problems that may arise while working with Clojure. The book is divided into three sections giving you the freedom skip to the section of your choice depending on the problem faced.