<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY % BOOK_ENTITIES SYSTEM "master.ent">
%BOOK_ENTITIES;

]>
<book>
    <bookinfo>
        <title>Reliable group communication with JGroups 3.x</title>
        <pubdate>August 2011</pubdate>
        <copyright>
            <year>1998-2006</year>
            <holder>Bela Ban</holder>
        </copyright>
         <copyright>
            <year>2006-2012</year>
            <holder>Red Hat Inc</holder>
        </copyright>

        <authorgroup>
            <author>
                <firstname>Bela</firstname>
                <surname> Ban</surname>
                <affiliation>
                    <shortaffil>Red Hat, Inc.</shortaffil>
                    <jobtitle>Project Lead</jobtitle>
                    <orgdiv>JBoss</orgdiv>
                </affiliation>
                <email>belaban@yahoo.com</email>
            </author>
            <author>
                <firstname>Vladimir</firstname>
                <surname>Blagojevic</surname>
                <affiliation>
                    <shortaffil>Red Hat, Inc.</shortaffil>
                    <orgdiv>JBoss</orgdiv>
                </affiliation>
                <email>vblagoje@redhat.com</email>
            </author>
        </authorgroup>
        <legalnotice>
            <para>This document is licensed under the
                <ulink url="http://creativecommons.org/licenses/by-sa/3.0/us/legalcode">
                    Creative Commons Attribution-ShareAlike (CC-BY-SA) 3.0
                </ulink>
            </para>
        </legalnotice>
    </bookinfo>

    <preface id="Preface">
        <title>Preface</title>

        <para>This is the JGroups manual. It provides information about:
            <orderedlist>
                <listitem>
                    <para>Installation and configuration</para>
                </listitem>
                <listitem>
                    <para>Using JGroups (the API)</para>
                </listitem>
                <listitem>
                    <para>Configuration of the JGroups protocols</para>
                </listitem>
            </orderedlist>
        </para>

        <para>
            The focus is on how to <emphasis>use</emphasis> JGroups, not on how JGroups is implemented.
        </para>

        <para>Here are a couple of points I want to abide by throughout this book:
            <orderedlist>
                <listitem>
                    <para>I like brevity. I will strive to describe concepts as
                        clearly as possible (for a non-native English speaker) and will
                        refrain from saying more than I have to to make a point.</para>
                </listitem>
                <listitem>
                    <para>I like simplicity. Keep It Simple and Stupid. This is
                        one of the biggest goals I have both in writing this manual
                        and in writing JGroups. It is easy to explain simple
                        concepts in complex terms, but it is hard to explain a
                        complex system in simple terms. I'll try to do the latter.
                    </para>
                </listitem>
            </orderedlist>
        </para>


        <bridgehead>So, how did it all start?</bridgehead>

        <para>I spent 1998-1999 at the Computer Science Department at
            Cornell University as a post-doc, in Ken Birman's group. Ken is
            credited with inventing the group communication paradigm,
            especially the Virtual Synchrony model. At the time they were
            working on their third generation group communication prototype,
            called Ensemble. Ensemble followed Horus (written in C by Robbert
            VanRenesse), which followed ISIS (written by Ken Birman, also in
            C). Ensemble was written in OCaml, developed at INRIA, and is a
            functional language and related to ML. I never liked the OCaml
            language, which in my opinion has a hideous syntax. Therefore I
            never got warm with Ensemble either.</para>

        <para>However, Ensemble had a Java interface (implemented by a
            student in a semester project) which allowed me to program in Java
            and use Ensemble underneath. The Java part would require that an
            Ensemble process was running somewhere on the same machine, and would connect to it via a
            bidirectional pipe. The student had developed a simple protocol
            for talking to the Ensemble engine, and extended the engine as
            well to talk back to Java.</para>

        <para>However, I still needed to compile and install the Ensemble
            runtime for each different platform, which is exactly why Java was
            developed in the first place: portability.</para>

        <para>Therefore I started writing a simple framework (now
            <classname>JChannel</classname>
            ), which would allow me to treat
            Ensemble as just another group communication transport, which
            could be replaced at any time by a pure Java solution. And soon I
            found myself working on a pure Java implementation of the group
            communication transport (now:
            <classname>ProtocolStack</classname>
            ). I figured that a pure Java
            implementation would have a much bigger impact that something
            written in Ensemble. In the end I didn't spend much time writing
            scientific papers that nobody would read anyway (I guess I'm not a
            good scientist, at least not a theoretical one), but rather code
            for JGroups, which could have a much bigger impact. For me,
            knowing that real-life projects/products are using JGroups is
            much more satisfactory than having a paper accepted at a
            conference/journal.
        </para>

        <para>That's why, after my time was up, I left Cornell and
            academia altogether, and started a job in the telecom industry in Silicon Valley.
        </para>

        <para>At around that time (May 2000), SourceForge had just opened
            its site, and I decided to use it for hosting JGroups.
            This was a major boost for JGroups because now other developers
            could work on the code. From then on, the page hit and download
            numbers for JGroups have steadily risen.
        </para>

        <para>
            In the fall of 2002, Sacha Labourey contacted me, letting me know that JGroups was being used by JBoss for
            their clustering implementation. I joined JBoss in 2003 and have been working on JGroups and JBossCache. My
            goal is to make JGroups the most widely used clustering software in Java ...
        </para>

        <para>I want to thank all contributors to JGroups, present and past, for their work. Without you,
            this project would never have taken off the ground.
        </para>

        <para>I also want to thank Ken Birman and Robbert VanRenesse for many fruitful discussions of all aspects
            of group communication in particular and distributed systems in general.
        </para>

        <para>I want to dedicate this manual to Jeannette and Michelle.</para>

        <para>Bela Ban, San Jose, Aug 2002, Kreuzlingen Switzerland 2011</para>

    </preface>


    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/overview.xml"/>
    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/installation.xml.tmp"/>
    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/api.xml"/>
    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/blocks.xml"/>
    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/advanced.xml"/>
    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/writing.xml"/>
    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="modules/protocols.xml.tmp"/>

    <!--<bibliography>

        <bibliomixed id="Ensemble:1997">
            <title>The Ensemble Distributed Communication System</title>
            ,
            <orgname>CS Dept Cornell University</orgname>
            ,
            <pubdate>1997</pubdate>
            .
            <releaseinfo>
                <ulink
                        url="http://www.cs.cornell.edu/Info/Projects/Ensemble/index.html"/>
            </releaseinfo>
            .
        </bibliomixed>

        <bibliomixed id="Gamma:1995">
            <firstname>Erich</firstname>
            <surname>Gamma</surname>
            ,
            <firstname>Richard</firstname>
            <surname>Helm</surname>
            ,
            <firstname>Ralph</firstname>
            <surname>Johnson</surname>
            , and
            <firstname>John</firstname>
            <surname>Vlissides</surname>
            .
            <title>Design Patterns: Elements of Reusable Object-Oriented
                Software</title>
            .
            <publishername>Addison-Wesley</publishername>
            ,
            <pubdate>1995</pubdate>
            .
        </bibliomixed>

    </bibliography>-->

</book>

