Book Image

Learning Network Programming with Java

Book Image

Learning Network Programming with Java

Overview of this book

Network-aware applications are becoming more prevalent and play an ever-increasing role in the world today. Connecting and using an Internet-based service is a frequent requirement for many applications. Java provides numerous classes that have evolved over the years to meet evolving network needs. These range from low-level socket and IP-based approaches to those encapsulated in software services. This book explores how Java supports networks, starting with the basics and then advancing to more complex topics. An overview of each relevant network technology is presented followed by detailed examples of how to use Java to support these technologies. We start with the basics of networking and then explore how Java supports the development of client/server and peer-to-peer applications. The NIO packages are examined as well as multitasking and how network applications can address practical issues such as security. A discussion on networking concepts will put many network issues into perspective and let you focus on the appropriate technology for the problem at hand. The examples used will provide a good starting point to develop similar capabilities for many of your network needs
Table of Contents (16 chapters)
Learning Network Programming with Java
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Introduction to buffers


Buffers hold data temporarily because it is being moved to and from channels. When a buffer is created, it is created with a fixed size or capacity. Part or all of a buffer's memory can be used with several Buffer class fields available to manage the data in a buffer.

The Buffer class is abstract. However, it possesses the basic methods used to manipulate a buffer, including:

  • capacity: This returns the number of elements in the buffer

  • limit: This returns the first index of the buffer that should not be accessed

  • position: This returns the index of the next element to be read or written

The element depends on the buffer type.

The mark and reset methods also control the position within a buffer. The mark method will set the buffer's mark to its position. The reset method restores the mark position to the previously marked position. The following code shows the relationships between various buffer terms:

0 <= mark <= position <= limit <= capacity

A buffer can be...