Book Image

Apache Spark 2.x for Java Developers

By : Sourav Gulati, Sumit Kumar
Book Image

Apache Spark 2.x for Java Developers

By: Sourav Gulati, Sumit Kumar

Overview of this book

Apache Spark is the buzzword in the big data industry right now, especially with the increasing need for real-time streaming and data processing. While Spark is built on Scala, the Spark Java API exposes all the Spark features available in the Scala version for Java developers. This book will show you how you can implement various functionalities of the Apache Spark framework in Java, without stepping out of your comfort zone. The book starts with an introduction to the Apache Spark 2.x ecosystem, followed by explaining how to install and configure Spark, and refreshes the Java concepts that will be useful to you when consuming Apache Spark's APIs. You will explore RDD and its associated common Action and Transformation Java APIs, set up a production-like clustered environment, and work with Spark SQL. Moving on, you will perform near-real-time processing with Spark streaming, Machine Learning analytics with Spark MLlib, and graph processing with GraphX, all using various Java packages. By the end of the book, you will have a solid foundation in implementing components in the Spark framework in Java to build fast, real-time applications.
Table of Contents (19 chapters)
Title Page
Credits
Foreword
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Terminal operations


Terminal operations act as the trigger point in a pipelined stream operation to trigger execution. Terminal operations either return a void or a non-stream type object and once the pipelined operations have been executed on the stream, the stream becomes redundant. A Terminal operation is always required for a pipelined stream operation to be executed.

Stream operations can further be classified as short-circuiting operations. An intermediate operation is said to be short circuited when an infinite input produces a finite stream such as in the case of the limit() method. Similarly, short circuiting operations in the case of terminal operations is when an infinite input may terminate in finite time, as is the case for the methods anyMatch(), findAny(), and so on.

Streams also support parallelism , but in the case of stateful operations, since each parallel operation can have its own state, a parallel stateful operation may have to undergo multiple passes to complete the...