Book Image

Mastering Concurrency Programming with Java 9 - Second Edition

By : Javier Fernández González
Book Image

Mastering Concurrency Programming with Java 9 - Second Edition

By: Javier Fernández González

Overview of this book

Concurrency programming allows several large tasks to be divided into smaller sub-tasks, which are further processed as individual tasks that run in parallel. Java 9 includes a comprehensive API with lots of ready-to-use components for easily implementing powerful concurrency applications, but with high flexibility so you can adapt these components to your needs. The book starts with a full description of the design principles of concurrent applications and explains how to parallelize a sequential algorithm. You will then be introduced to Threads and Runnables, which are an integral part of Java 9's concurrency API. You will see how to use all the components of the Java concurrency API, from the basics to the most advanced techniques, and will implement them in powerful real-world concurrency applications. The book ends with a detailed description of the tools and techniques you can use to test a concurrent Java application, along with a brief insight into other concurrency mechanisms in JVM.
Table of Contents (21 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback

Chapter 6. Running Tasks Divided into Phases - The Phaser Class

The most important element in a concurrent API is the synchronization mechanism it offers to the programmer. Synchronization is the coordination of two or more tasks to get the desired result. You can synchronize the execution of two or more tasks, when they have to be executed in a predefined order, or synchronize the access to a shared resource, when only one thread at a time can execute a fragment of code or modify a block of memory. The Java 9 concurrency API provides a lot of synchronization mechanisms, from the basic synchronized keyword and the Lock interface and their implementations, to protect a critical section, to the more advanced CyclicBarrier or CountDownLatch classes, which allow you to synchronize the order of execution of different tasks. In Java 7, the concurrency API introduces the Phaser class. This class provides a powerful mechanism (phaser) to execute tasks divided into phases. The task can ask the Phaser...