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

Using FreePastry


Pastry (http://www.freepastry.org/) is a P2P routing overlay system. FreePastry (http://www.freepastry.org/FreePastry/) is an open source implementation of Pastry and is simple enough for us to use to illustrate many of the features of a P2P system. Pastry will route messages with a network of n nodes in O(log n) steps. That is, given a network of nodes, it requires, at most, log base 2 of n steps to reach the node. This is an efficient routing approach. However, while it may only require traversing three nodes to get to a resource, it may require a considerable number of IP hops to get to it.

Pastry uses the concept of leaf sets in the routing process. Each node has a leaf set. A leaf set is a collection of GUIDS and IP addresses of nodes that are numerically closest to this node. The nodes are logically arranged in a circle, as shown next.

In the following figure, each dot represents a node with an identifier. The addresses used here range from 0 to FFFFFF. The real addresses...