blob: 174350e3bf7ac4f8139f2fa519d5174cf0cfa2e7 [file] [log] [blame]
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<!--[if IE]><meta http-equiv="X-UA-Compatible" content="IE=edge"><![endif]-->
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="generator" content="Asciidoctor 1.5.3">
<title>Introduction to the Virgo for Apache Tomcat</title>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700">
<style>
/* Asciidoctor default stylesheet | MIT License | http://asciidoctor.org */
/* Remove comment around @import statement below when using as a custom stylesheet */
/*@import "https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700";*/
article,aside,details,figcaption,figure,footer,header,hgroup,main,nav,section,summary{display:block}
audio,canvas,video{display:inline-block}
audio:not([controls]){display:none;height:0}
[hidden],template{display:none}
script{display:none!important}
html{font-family:sans-serif;-ms-text-size-adjust:100%;-webkit-text-size-adjust:100%}
body{margin:0}
a{background:transparent}
a:focus{outline:thin dotted}
a:active,a:hover{outline:0}
h1{font-size:2em;margin:.67em 0}
abbr[title]{border-bottom:1px dotted}
b,strong{font-weight:bold}
dfn{font-style:italic}
hr{-moz-box-sizing:content-box;box-sizing:content-box;height:0}
mark{background:#ff0;color:#000}
code,kbd,pre,samp{font-family:monospace;font-size:1em}
pre{white-space:pre-wrap}
q{quotes:"\201C" "\201D" "\2018" "\2019"}
small{font-size:80%}
sub,sup{font-size:75%;line-height:0;position:relative;vertical-align:baseline}
sup{top:-.5em}
sub{bottom:-.25em}
img{border:0}
svg:not(:root){overflow:hidden}
figure{margin:0}
fieldset{border:1px solid silver;margin:0 2px;padding:.35em .625em .75em}
legend{border:0;padding:0}
button,input,select,textarea{font-family:inherit;font-size:100%;margin:0}
button,input{line-height:normal}
button,select{text-transform:none}
button,html input[type="button"],input[type="reset"],input[type="submit"]{-webkit-appearance:button;cursor:pointer}
button[disabled],html input[disabled]{cursor:default}
input[type="checkbox"],input[type="radio"]{box-sizing:border-box;padding:0}
input[type="search"]{-webkit-appearance:textfield;-moz-box-sizing:content-box;-webkit-box-sizing:content-box;box-sizing:content-box}
input[type="search"]::-webkit-search-cancel-button,input[type="search"]::-webkit-search-decoration{-webkit-appearance:none}
button::-moz-focus-inner,input::-moz-focus-inner{border:0;padding:0}
textarea{overflow:auto;vertical-align:top}
table{border-collapse:collapse;border-spacing:0}
*,*:before,*:after{-moz-box-sizing:border-box;-webkit-box-sizing:border-box;box-sizing:border-box}
html,body{font-size:100%}
body{background:#fff;color:rgba(0,0,0,.8);padding:0;margin:0;font-family:"Noto Serif","DejaVu Serif",serif;font-weight:400;font-style:normal;line-height:1;position:relative;cursor:auto}
a:hover{cursor:pointer}
img,object,embed{max-width:100%;height:auto}
object,embed{height:100%}
img{-ms-interpolation-mode:bicubic}
.left{float:left!important}
.right{float:right!important}
.text-left{text-align:left!important}
.text-right{text-align:right!important}
.text-center{text-align:center!important}
.text-justify{text-align:justify!important}
.hide{display:none}
body{-webkit-font-smoothing:antialiased}
img,object,svg{display:inline-block;vertical-align:middle}
textarea{height:auto;min-height:50px}
select{width:100%}
.center{margin-left:auto;margin-right:auto}
.spread{width:100%}
p.lead,.paragraph.lead>p,#preamble>.sectionbody>.paragraph:first-of-type p{font-size:1.21875em;line-height:1.6}
.subheader,.admonitionblock td.content>.title,.audioblock>.title,.exampleblock>.title,.imageblock>.title,.listingblock>.title,.literalblock>.title,.stemblock>.title,.openblock>.title,.paragraph>.title,.quoteblock>.title,table.tableblock>.title,.verseblock>.title,.videoblock>.title,.dlist>.title,.olist>.title,.ulist>.title,.qlist>.title,.hdlist>.title{line-height:1.45;color:#7a2518;font-weight:400;margin-top:0;margin-bottom:.25em}
div,dl,dt,dd,ul,ol,li,h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6,pre,form,p,blockquote,th,td{margin:0;padding:0;direction:ltr}
a{color:#2156a5;text-decoration:underline;line-height:inherit}
a:hover,a:focus{color:#1d4b8f}
a img{border:none}
p{font-family:inherit;font-weight:400;font-size:1em;line-height:1.6;margin-bottom:1.25em;text-rendering:optimizeLegibility}
p aside{font-size:.875em;line-height:1.35;font-style:italic}
h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{font-family:"Open Sans","DejaVu Sans",sans-serif;font-weight:300;font-style:normal;color:#ba3925;text-rendering:optimizeLegibility;margin-top:1em;margin-bottom:.5em;line-height:1.0125em}
h1 small,h2 small,h3 small,#toctitle small,.sidebarblock>.content>.title small,h4 small,h5 small,h6 small{font-size:60%;color:#e99b8f;line-height:0}
h1{font-size:2.125em}
h2{font-size:1.6875em}
h3,#toctitle,.sidebarblock>.content>.title{font-size:1.375em}
h4,h5{font-size:1.125em}
h6{font-size:1em}
hr{border:solid #ddddd8;border-width:1px 0 0;clear:both;margin:1.25em 0 1.1875em;height:0}
em,i{font-style:italic;line-height:inherit}
strong,b{font-weight:bold;line-height:inherit}
small{font-size:60%;line-height:inherit}
code{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;font-weight:400;color:rgba(0,0,0,.9)}
ul,ol,dl{font-size:1em;line-height:1.6;margin-bottom:1.25em;list-style-position:outside;font-family:inherit}
ul,ol,ul.no-bullet,ol.no-bullet{margin-left:1.5em}
ul li ul,ul li ol{margin-left:1.25em;margin-bottom:0;font-size:1em}
ul.square li ul,ul.circle li ul,ul.disc li ul{list-style:inherit}
ul.square{list-style-type:square}
ul.circle{list-style-type:circle}
ul.disc{list-style-type:disc}
ul.no-bullet{list-style:none}
ol li ul,ol li ol{margin-left:1.25em;margin-bottom:0}
dl dt{margin-bottom:.3125em;font-weight:bold}
dl dd{margin-bottom:1.25em}
abbr,acronym{text-transform:uppercase;font-size:90%;color:rgba(0,0,0,.8);border-bottom:1px dotted #ddd;cursor:help}
abbr{text-transform:none}
blockquote{margin:0 0 1.25em;padding:.5625em 1.25em 0 1.1875em;border-left:1px solid #ddd}
blockquote cite{display:block;font-size:.9375em;color:rgba(0,0,0,.6)}
blockquote cite:before{content:"\2014 \0020"}
blockquote cite a,blockquote cite a:visited{color:rgba(0,0,0,.6)}
blockquote,blockquote p{line-height:1.6;color:rgba(0,0,0,.85)}
@media only screen and (min-width:768px){h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2}
h1{font-size:2.75em}
h2{font-size:2.3125em}
h3,#toctitle,.sidebarblock>.content>.title{font-size:1.6875em}
h4{font-size:1.4375em}}
table{background:#fff;margin-bottom:1.25em;border:solid 1px #dedede}
table thead,table tfoot{background:#f7f8f7;font-weight:bold}
table thead tr th,table thead tr td,table tfoot tr th,table tfoot tr td{padding:.5em .625em .625em;font-size:inherit;color:rgba(0,0,0,.8);text-align:left}
table tr th,table tr td{padding:.5625em .625em;font-size:inherit;color:rgba(0,0,0,.8)}
table tr.even,table tr.alt,table tr:nth-of-type(even){background:#f8f8f7}
table thead tr th,table tfoot tr th,table tbody tr td,table tr td,table tfoot tr td{display:table-cell;line-height:1.6}
body{tab-size:4}
h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2;word-spacing:-.05em}
h1 strong,h2 strong,h3 strong,#toctitle strong,.sidebarblock>.content>.title strong,h4 strong,h5 strong,h6 strong{font-weight:400}
.clearfix:before,.clearfix:after,.float-group:before,.float-group:after{content:" ";display:table}
.clearfix:after,.float-group:after{clear:both}
*:not(pre)>code{font-size:.9375em;font-style:normal!important;letter-spacing:0;padding:.1em .5ex;word-spacing:-.15em;background-color:#f7f7f8;-webkit-border-radius:4px;border-radius:4px;line-height:1.45;text-rendering:optimizeSpeed}
pre,pre>code{line-height:1.45;color:rgba(0,0,0,.9);font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;font-weight:400;text-rendering:optimizeSpeed}
.keyseq{color:rgba(51,51,51,.8)}
kbd{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;display:inline-block;color:rgba(0,0,0,.8);font-size:.65em;line-height:1.45;background-color:#f7f7f7;border:1px solid #ccc;-webkit-border-radius:3px;border-radius:3px;-webkit-box-shadow:0 1px 0 rgba(0,0,0,.2),0 0 0 .1em white inset;box-shadow:0 1px 0 rgba(0,0,0,.2),0 0 0 .1em #fff inset;margin:0 .15em;padding:.2em .5em;vertical-align:middle;position:relative;top:-.1em;white-space:nowrap}
.keyseq kbd:first-child{margin-left:0}
.keyseq kbd:last-child{margin-right:0}
.menuseq,.menu{color:rgba(0,0,0,.8)}
b.button:before,b.button:after{position:relative;top:-1px;font-weight:400}
b.button:before{content:"[";padding:0 3px 0 2px}
b.button:after{content:"]";padding:0 2px 0 3px}
p a>code:hover{color:rgba(0,0,0,.9)}
#header,#content,#footnotes,#footer{width:100%;margin-left:auto;margin-right:auto;margin-top:0;margin-bottom:0;max-width:62.5em;*zoom:1;position:relative;padding-left:.9375em;padding-right:.9375em}
#header:before,#header:after,#content:before,#content:after,#footnotes:before,#footnotes:after,#footer:before,#footer:after{content:" ";display:table}
#header:after,#content:after,#footnotes:after,#footer:after{clear:both}
#content{margin-top:1.25em}
#content:before{content:none}
#header>h1:first-child{color:rgba(0,0,0,.85);margin-top:2.25rem;margin-bottom:0}
#header>h1:first-child+#toc{margin-top:8px;border-top:1px solid #ddddd8}
#header>h1:only-child,body.toc2 #header>h1:nth-last-child(2){border-bottom:1px solid #ddddd8;padding-bottom:8px}
#header .details{border-bottom:1px solid #ddddd8;line-height:1.45;padding-top:.25em;padding-bottom:.25em;padding-left:.25em;color:rgba(0,0,0,.6);display:-ms-flexbox;display:-webkit-flex;display:flex;-ms-flex-flow:row wrap;-webkit-flex-flow:row wrap;flex-flow:row wrap}
#header .details span:first-child{margin-left:-.125em}
#header .details span.email a{color:rgba(0,0,0,.85)}
#header .details br{display:none}
#header .details br+span:before{content:"\00a0\2013\00a0"}
#header .details br+span.author:before{content:"\00a0\22c5\00a0";color:rgba(0,0,0,.85)}
#header .details br+span#revremark:before{content:"\00a0|\00a0"}
#header #revnumber{text-transform:capitalize}
#header #revnumber:after{content:"\00a0"}
#content>h1:first-child:not([class]){color:rgba(0,0,0,.85);border-bottom:1px solid #ddddd8;padding-bottom:8px;margin-top:0;padding-top:1rem;margin-bottom:1.25rem}
#toc{border-bottom:1px solid #efefed;padding-bottom:.5em}
#toc>ul{margin-left:.125em}
#toc ul.sectlevel0>li>a{font-style:italic}
#toc ul.sectlevel0 ul.sectlevel1{margin:.5em 0}
#toc ul{font-family:"Open Sans","DejaVu Sans",sans-serif;list-style-type:none}
#toc li{line-height:1.3334;margin-top:.3334em}
#toc a{text-decoration:none}
#toc a:active{text-decoration:underline}
#toctitle{color:#7a2518;font-size:1.2em}
@media only screen and (min-width:768px){#toctitle{font-size:1.375em}
body.toc2{padding-left:15em;padding-right:0}
#toc.toc2{margin-top:0!important;background-color:#f8f8f7;position:fixed;width:15em;left:0;top:0;border-right:1px solid #efefed;border-top-width:0!important;border-bottom-width:0!important;z-index:1000;padding:1.25em 1em;height:100%;overflow:auto}
#toc.toc2 #toctitle{margin-top:0;margin-bottom:.8rem;font-size:1.2em}
#toc.toc2>ul{font-size:.9em;margin-bottom:0}
#toc.toc2 ul ul{margin-left:0;padding-left:1em}
#toc.toc2 ul.sectlevel0 ul.sectlevel1{padding-left:0;margin-top:.5em;margin-bottom:.5em}
body.toc2.toc-right{padding-left:0;padding-right:15em}
body.toc2.toc-right #toc.toc2{border-right-width:0;border-left:1px solid #efefed;left:auto;right:0}}
@media only screen and (min-width:1280px){body.toc2{padding-left:20em;padding-right:0}
#toc.toc2{width:20em}
#toc.toc2 #toctitle{font-size:1.375em}
#toc.toc2>ul{font-size:.95em}
#toc.toc2 ul ul{padding-left:1.25em}
body.toc2.toc-right{padding-left:0;padding-right:20em}}
#content #toc{border-style:solid;border-width:1px;border-color:#e0e0dc;margin-bottom:1.25em;padding:1.25em;background:#f8f8f7;-webkit-border-radius:4px;border-radius:4px}
#content #toc>:first-child{margin-top:0}
#content #toc>:last-child{margin-bottom:0}
#footer{max-width:100%;background-color:rgba(0,0,0,.8);padding:1.25em}
#footer-text{color:rgba(255,255,255,.8);line-height:1.44}
.sect1{padding-bottom:.625em}
@media only screen and (min-width:768px){.sect1{padding-bottom:1.25em}}
.sect1+.sect1{border-top:1px solid #efefed}
#content h1>a.anchor,h2>a.anchor,h3>a.anchor,#toctitle>a.anchor,.sidebarblock>.content>.title>a.anchor,h4>a.anchor,h5>a.anchor,h6>a.anchor{position:absolute;z-index:1001;width:1.5ex;margin-left:-1.5ex;display:block;text-decoration:none!important;visibility:hidden;text-align:center;font-weight:400}
#content h1>a.anchor:before,h2>a.anchor:before,h3>a.anchor:before,#toctitle>a.anchor:before,.sidebarblock>.content>.title>a.anchor:before,h4>a.anchor:before,h5>a.anchor:before,h6>a.anchor:before{content:"\00A7";font-size:.85em;display:block;padding-top:.1em}
#content h1:hover>a.anchor,#content h1>a.anchor:hover,h2:hover>a.anchor,h2>a.anchor:hover,h3:hover>a.anchor,#toctitle:hover>a.anchor,.sidebarblock>.content>.title:hover>a.anchor,h3>a.anchor:hover,#toctitle>a.anchor:hover,.sidebarblock>.content>.title>a.anchor:hover,h4:hover>a.anchor,h4>a.anchor:hover,h5:hover>a.anchor,h5>a.anchor:hover,h6:hover>a.anchor,h6>a.anchor:hover{visibility:visible}
#content h1>a.link,h2>a.link,h3>a.link,#toctitle>a.link,.sidebarblock>.content>.title>a.link,h4>a.link,h5>a.link,h6>a.link{color:#ba3925;text-decoration:none}
#content h1>a.link:hover,h2>a.link:hover,h3>a.link:hover,#toctitle>a.link:hover,.sidebarblock>.content>.title>a.link:hover,h4>a.link:hover,h5>a.link:hover,h6>a.link:hover{color:#a53221}
.audioblock,.imageblock,.literalblock,.listingblock,.stemblock,.videoblock{margin-bottom:1.25em}
.admonitionblock td.content>.title,.audioblock>.title,.exampleblock>.title,.imageblock>.title,.listingblock>.title,.literalblock>.title,.stemblock>.title,.openblock>.title,.paragraph>.title,.quoteblock>.title,table.tableblock>.title,.verseblock>.title,.videoblock>.title,.dlist>.title,.olist>.title,.ulist>.title,.qlist>.title,.hdlist>.title{text-rendering:optimizeLegibility;text-align:left;font-family:"Noto Serif","DejaVu Serif",serif;font-size:1rem;font-style:italic}
table.tableblock>caption.title{white-space:nowrap;overflow:visible;max-width:0}
.paragraph.lead>p,#preamble>.sectionbody>.paragraph:first-of-type p{color:rgba(0,0,0,.85)}
table.tableblock #preamble>.sectionbody>.paragraph:first-of-type p{font-size:inherit}
.admonitionblock>table{border-collapse:separate;border:0;background:none;width:100%}
.admonitionblock>table td.icon{text-align:center;width:80px}
.admonitionblock>table td.icon img{max-width:none}
.admonitionblock>table td.icon .title{font-weight:bold;font-family:"Open Sans","DejaVu Sans",sans-serif;text-transform:uppercase}
.admonitionblock>table td.content{padding-left:1.125em;padding-right:1.25em;border-left:1px solid #ddddd8;color:rgba(0,0,0,.6)}
.admonitionblock>table td.content>:last-child>:last-child{margin-bottom:0}
.exampleblock>.content{border-style:solid;border-width:1px;border-color:#e6e6e6;margin-bottom:1.25em;padding:1.25em;background:#fff;-webkit-border-radius:4px;border-radius:4px}
.exampleblock>.content>:first-child{margin-top:0}
.exampleblock>.content>:last-child{margin-bottom:0}
.sidebarblock{border-style:solid;border-width:1px;border-color:#e0e0dc;margin-bottom:1.25em;padding:1.25em;background:#f8f8f7;-webkit-border-radius:4px;border-radius:4px}
.sidebarblock>:first-child{margin-top:0}
.sidebarblock>:last-child{margin-bottom:0}
.sidebarblock>.content>.title{color:#7a2518;margin-top:0;text-align:center}
.exampleblock>.content>:last-child>:last-child,.exampleblock>.content .olist>ol>li:last-child>:last-child,.exampleblock>.content .ulist>ul>li:last-child>:last-child,.exampleblock>.content .qlist>ol>li:last-child>:last-child,.sidebarblock>.content>:last-child>:last-child,.sidebarblock>.content .olist>ol>li:last-child>:last-child,.sidebarblock>.content .ulist>ul>li:last-child>:last-child,.sidebarblock>.content .qlist>ol>li:last-child>:last-child{margin-bottom:0}
.literalblock pre,.listingblock pre:not(.highlight),.listingblock pre[class="highlight"],.listingblock pre[class^="highlight "],.listingblock pre.CodeRay,.listingblock pre.prettyprint{background:#f7f7f8}
.sidebarblock .literalblock pre,.sidebarblock .listingblock pre:not(.highlight),.sidebarblock .listingblock pre[class="highlight"],.sidebarblock .listingblock pre[class^="highlight "],.sidebarblock .listingblock pre.CodeRay,.sidebarblock .listingblock pre.prettyprint{background:#f2f1f1}
.literalblock pre,.literalblock pre[class],.listingblock pre,.listingblock pre[class]{-webkit-border-radius:4px;border-radius:4px;word-wrap:break-word;padding:1em;font-size:.8125em}
.literalblock pre.nowrap,.literalblock pre[class].nowrap,.listingblock pre.nowrap,.listingblock pre[class].nowrap{overflow-x:auto;white-space:pre;word-wrap:normal}
@media only screen and (min-width:768px){.literalblock pre,.literalblock pre[class],.listingblock pre,.listingblock pre[class]{font-size:.90625em}}
@media only screen and (min-width:1280px){.literalblock pre,.literalblock pre[class],.listingblock pre,.listingblock pre[class]{font-size:1em}}
.literalblock.output pre{color:#f7f7f8;background-color:rgba(0,0,0,.9)}
.listingblock pre.highlightjs{padding:0}
.listingblock pre.highlightjs>code{padding:1em;-webkit-border-radius:4px;border-radius:4px}
.listingblock pre.prettyprint{border-width:0}
.listingblock>.content{position:relative}
.listingblock code[data-lang]:before{display:none;content:attr(data-lang);position:absolute;font-size:.75em;top:.425rem;right:.5rem;line-height:1;text-transform:uppercase;color:#999}
.listingblock:hover code[data-lang]:before{display:block}
.listingblock.terminal pre .command:before{content:attr(data-prompt);padding-right:.5em;color:#999}
.listingblock.terminal pre .command:not([data-prompt]):before{content:"$"}
table.pyhltable{border-collapse:separate;border:0;margin-bottom:0;background:none}
table.pyhltable td{vertical-align:top;padding-top:0;padding-bottom:0;line-height:1.45}
table.pyhltable td.code{padding-left:.75em;padding-right:0}
pre.pygments .lineno,table.pyhltable td:not(.code){color:#999;padding-left:0;padding-right:.5em;border-right:1px solid #ddddd8}
pre.pygments .lineno{display:inline-block;margin-right:.25em}
table.pyhltable .linenodiv{background:none!important;padding-right:0!important}
.quoteblock{margin:0 1em 1.25em 1.5em;display:table}
.quoteblock>.title{margin-left:-1.5em;margin-bottom:.75em}
.quoteblock blockquote,.quoteblock blockquote p{color:rgba(0,0,0,.85);font-size:1.15rem;line-height:1.75;word-spacing:.1em;letter-spacing:0;font-style:italic;text-align:justify}
.quoteblock blockquote{margin:0;padding:0;border:0}
.quoteblock blockquote:before{content:"\201c";float:left;font-size:2.75em;font-weight:bold;line-height:.6em;margin-left:-.6em;color:#7a2518;text-shadow:0 1px 2px rgba(0,0,0,.1)}
.quoteblock blockquote>.paragraph:last-child p{margin-bottom:0}
.quoteblock .attribution{margin-top:.5em;margin-right:.5ex;text-align:right}
.quoteblock .quoteblock{margin-left:0;margin-right:0;padding:.5em 0;border-left:3px solid rgba(0,0,0,.6)}
.quoteblock .quoteblock blockquote{padding:0 0 0 .75em}
.quoteblock .quoteblock blockquote:before{display:none}
.verseblock{margin:0 1em 1.25em 1em}
.verseblock pre{font-family:"Open Sans","DejaVu Sans",sans;font-size:1.15rem;color:rgba(0,0,0,.85);font-weight:300;text-rendering:optimizeLegibility}
.verseblock pre strong{font-weight:400}
.verseblock .attribution{margin-top:1.25rem;margin-left:.5ex}
.quoteblock .attribution,.verseblock .attribution{font-size:.9375em;line-height:1.45;font-style:italic}
.quoteblock .attribution br,.verseblock .attribution br{display:none}
.quoteblock .attribution cite,.verseblock .attribution cite{display:block;letter-spacing:-.025em;color:rgba(0,0,0,.6)}
.quoteblock.abstract{margin:0 0 1.25em 0;display:block}
.quoteblock.abstract blockquote,.quoteblock.abstract blockquote p{text-align:left;word-spacing:0}
.quoteblock.abstract blockquote:before,.quoteblock.abstract blockquote p:first-of-type:before{display:none}
table.tableblock{max-width:100%;border-collapse:separate}
table.tableblock td>.paragraph:last-child p>p:last-child,table.tableblock th>p:last-child,table.tableblock td>p:last-child{margin-bottom:0}
table.tableblock,th.tableblock,td.tableblock{border:0 solid #dedede}
table.grid-all th.tableblock,table.grid-all td.tableblock{border-width:0 1px 1px 0}
table.grid-all tfoot>tr>th.tableblock,table.grid-all tfoot>tr>td.tableblock{border-width:1px 1px 0 0}
table.grid-cols th.tableblock,table.grid-cols td.tableblock{border-width:0 1px 0 0}
table.grid-all *>tr>.tableblock:last-child,table.grid-cols *>tr>.tableblock:last-child{border-right-width:0}
table.grid-rows th.tableblock,table.grid-rows td.tableblock{border-width:0 0 1px 0}
table.grid-all tbody>tr:last-child>th.tableblock,table.grid-all tbody>tr:last-child>td.tableblock,table.grid-all thead:last-child>tr>th.tableblock,table.grid-rows tbody>tr:last-child>th.tableblock,table.grid-rows tbody>tr:last-child>td.tableblock,table.grid-rows thead:last-child>tr>th.tableblock{border-bottom-width:0}
table.grid-rows tfoot>tr>th.tableblock,table.grid-rows tfoot>tr>td.tableblock{border-width:1px 0 0 0}
table.frame-all{border-width:1px}
table.frame-sides{border-width:0 1px}
table.frame-topbot{border-width:1px 0}
th.halign-left,td.halign-left{text-align:left}
th.halign-right,td.halign-right{text-align:right}
th.halign-center,td.halign-center{text-align:center}
th.valign-top,td.valign-top{vertical-align:top}
th.valign-bottom,td.valign-bottom{vertical-align:bottom}
th.valign-middle,td.valign-middle{vertical-align:middle}
table thead th,table tfoot th{font-weight:bold}
tbody tr th{display:table-cell;line-height:1.6;background:#f7f8f7}
tbody tr th,tbody tr th p,tfoot tr th,tfoot tr th p{color:rgba(0,0,0,.8);font-weight:bold}
p.tableblock>code:only-child{background:none;padding:0}
p.tableblock{font-size:1em}
td>div.verse{white-space:pre}
ol{margin-left:1.75em}
ul li ol{margin-left:1.5em}
dl dd{margin-left:1.125em}
dl dd:last-child,dl dd:last-child>:last-child{margin-bottom:0}
ol>li p,ul>li p,ul dd,ol dd,.olist .olist,.ulist .ulist,.ulist .olist,.olist .ulist{margin-bottom:.625em}
ul.unstyled,ol.unnumbered,ul.checklist,ul.none{list-style-type:none}
ul.unstyled,ol.unnumbered,ul.checklist{margin-left:.625em}
ul.checklist li>p:first-child>.fa-square-o:first-child,ul.checklist li>p:first-child>.fa-check-square-o:first-child{width:1em;font-size:.85em}
ul.checklist li>p:first-child>input[type="checkbox"]:first-child{width:1em;position:relative;top:1px}
ul.inline{margin:0 auto .625em auto;margin-left:-1.375em;margin-right:0;padding:0;list-style:none;overflow:hidden}
ul.inline>li{list-style:none;float:left;margin-left:1.375em;display:block}
ul.inline>li>*{display:block}
.unstyled dl dt{font-weight:400;font-style:normal}
ol.arabic{list-style-type:decimal}
ol.decimal{list-style-type:decimal-leading-zero}
ol.loweralpha{list-style-type:lower-alpha}
ol.upperalpha{list-style-type:upper-alpha}
ol.lowerroman{list-style-type:lower-roman}
ol.upperroman{list-style-type:upper-roman}
ol.lowergreek{list-style-type:lower-greek}
.hdlist>table,.colist>table{border:0;background:none}
.hdlist>table>tbody>tr,.colist>table>tbody>tr{background:none}
td.hdlist1,td.hdlist2{vertical-align:top;padding:0 .625em}
td.hdlist1{font-weight:bold;padding-bottom:1.25em}
.literalblock+.colist,.listingblock+.colist{margin-top:-.5em}
.colist>table tr>td:first-of-type{padding:0 .75em;line-height:1}
.colist>table tr>td:last-of-type{padding:.25em 0}
.thumb,.th{line-height:0;display:inline-block;border:solid 4px #fff;-webkit-box-shadow:0 0 0 1px #ddd;box-shadow:0 0 0 1px #ddd}
.imageblock.left,.imageblock[style*="float: left"]{margin:.25em .625em 1.25em 0}
.imageblock.right,.imageblock[style*="float: right"]{margin:.25em 0 1.25em .625em}
.imageblock>.title{margin-bottom:0}
.imageblock.thumb,.imageblock.th{border-width:6px}
.imageblock.thumb>.title,.imageblock.th>.title{padding:0 .125em}
.image.left,.image.right{margin-top:.25em;margin-bottom:.25em;display:inline-block;line-height:0}
.image.left{margin-right:.625em}
.image.right{margin-left:.625em}
a.image{text-decoration:none;display:inline-block}
a.image object{pointer-events:none}
sup.footnote,sup.footnoteref{font-size:.875em;position:static;vertical-align:super}
sup.footnote a,sup.footnoteref a{text-decoration:none}
sup.footnote a:active,sup.footnoteref a:active{text-decoration:underline}
#footnotes{padding-top:.75em;padding-bottom:.75em;margin-bottom:.625em}
#footnotes hr{width:20%;min-width:6.25em;margin:-.25em 0 .75em 0;border-width:1px 0 0 0}
#footnotes .footnote{padding:0 .375em 0 .225em;line-height:1.3334;font-size:.875em;margin-left:1.2em;text-indent:-1.05em;margin-bottom:.2em}
#footnotes .footnote a:first-of-type{font-weight:bold;text-decoration:none}
#footnotes .footnote:last-of-type{margin-bottom:0}
#content #footnotes{margin-top:-.625em;margin-bottom:0;padding:.75em 0}
.gist .file-data>table{border:0;background:#fff;width:100%;margin-bottom:0}
.gist .file-data>table td.line-data{width:99%}
div.unbreakable{page-break-inside:avoid}
.big{font-size:larger}
.small{font-size:smaller}
.underline{text-decoration:underline}
.overline{text-decoration:overline}
.line-through{text-decoration:line-through}
.aqua{color:#00bfbf}
.aqua-background{background-color:#00fafa}
.black{color:#000}
.black-background{background-color:#000}
.blue{color:#0000bf}
.blue-background{background-color:#0000fa}
.fuchsia{color:#bf00bf}
.fuchsia-background{background-color:#fa00fa}
.gray{color:#606060}
.gray-background{background-color:#7d7d7d}
.green{color:#006000}
.green-background{background-color:#007d00}
.lime{color:#00bf00}
.lime-background{background-color:#00fa00}
.maroon{color:#600000}
.maroon-background{background-color:#7d0000}
.navy{color:#000060}
.navy-background{background-color:#00007d}
.olive{color:#606000}
.olive-background{background-color:#7d7d00}
.purple{color:#600060}
.purple-background{background-color:#7d007d}
.red{color:#bf0000}
.red-background{background-color:#fa0000}
.silver{color:#909090}
.silver-background{background-color:#bcbcbc}
.teal{color:#006060}
.teal-background{background-color:#007d7d}
.white{color:#bfbfbf}
.white-background{background-color:#fafafa}
.yellow{color:#bfbf00}
.yellow-background{background-color:#fafa00}
span.icon>.fa{cursor:default}
.admonitionblock td.icon [class^="fa icon-"]{font-size:2.5em;text-shadow:1px 1px 2px rgba(0,0,0,.5);cursor:default}
.admonitionblock td.icon .icon-note:before{content:"\f05a";color:#19407c}
.admonitionblock td.icon .icon-tip:before{content:"\f0eb";text-shadow:1px 1px 2px rgba(155,155,0,.8);color:#111}
.admonitionblock td.icon .icon-warning:before{content:"\f071";color:#bf6900}
.admonitionblock td.icon .icon-caution:before{content:"\f06d";color:#bf3400}
.admonitionblock td.icon .icon-important:before{content:"\f06a";color:#bf0000}
.conum[data-value]{display:inline-block;color:#fff!important;background-color:rgba(0,0,0,.8);-webkit-border-radius:100px;border-radius:100px;text-align:center;font-size:.75em;width:1.67em;height:1.67em;line-height:1.67em;font-family:"Open Sans","DejaVu Sans",sans-serif;font-style:normal;font-weight:bold}
.conum[data-value] *{color:#fff!important}
.conum[data-value]+b{display:none}
.conum[data-value]:after{content:attr(data-value)}
pre .conum[data-value]{position:relative;top:-.125em}
b.conum *{color:inherit!important}
.conum:not([data-value]):empty{display:none}
dt,th.tableblock,td.content,div.footnote{text-rendering:optimizeLegibility}
h1,h2,p,td.content,span.alt{letter-spacing:-.01em}
p strong,td.content strong,div.footnote strong{letter-spacing:-.005em}
p,blockquote,dt,td.content,span.alt{font-size:1.0625rem}
p{margin-bottom:1.25rem}
.sidebarblock p,.sidebarblock dt,.sidebarblock td.content,p.tableblock{font-size:1em}
.exampleblock>.content{background-color:#fffef7;border-color:#e0e0dc;-webkit-box-shadow:0 1px 4px #e0e0dc;box-shadow:0 1px 4px #e0e0dc}
.print-only{display:none!important}
@media print{@page{margin:1.25cm .75cm}
*{-webkit-box-shadow:none!important;box-shadow:none!important;text-shadow:none!important}
a{color:inherit!important;text-decoration:underline!important}
a.bare,a[href^="#"],a[href^="mailto:"]{text-decoration:none!important}
a[href^="http:"]:not(.bare):after,a[href^="https:"]:not(.bare):after{content:"(" attr(href) ")";display:inline-block;font-size:.875em;padding-left:.25em}
abbr[title]:after{content:" (" attr(title) ")"}
pre,blockquote,tr,img,object,svg{page-break-inside:avoid}
thead{display:table-header-group}
svg{max-width:100%}
p,blockquote,dt,td.content{font-size:1em;orphans:3;widows:3}
h2,h3,#toctitle,.sidebarblock>.content>.title{page-break-after:avoid}
#toc,.sidebarblock,.exampleblock>.content{background:none!important}
#toc{border-bottom:1px solid #ddddd8!important;padding-bottom:0!important}
.sect1{padding-bottom:0!important}
.sect1+.sect1{border:0!important}
#header>h1:first-child{margin-top:1.25rem}
body.book #header{text-align:center}
body.book #header>h1:first-child{border:0!important;margin:2.5em 0 1em 0}
body.book #header .details{border:0!important;display:block;padding:0!important}
body.book #header .details span:first-child{margin-left:0!important}
body.book #header .details br{display:block}
body.book #header .details br+span:before{content:none!important}
body.book #toc{border:0!important;text-align:left!important;padding:0!important;margin:0!important}
body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-break-before:always}
.listingblock code[data-lang]:before{display:block}
#footer{background:none!important;padding:0 .9375em}
#footer-text{color:rgba(0,0,0,.6)!important;font-size:.9em}
.hide-on-print{display:none!important}
.print-only{display:block!important}
.hide-for-print{display:none!important}
.show-for-print{display:inherit!important}}
</style>
</head>
<body class="article">
<div id="header">
</div>
<div id="content">
<div class="sect1">
<h2 id="_introduction_to_the_virgo_for_apache_tomcat">Introduction to the Virgo for Apache Tomcat</h2>
<div class="sectionbody">
<div class="sect2">
<h3 id="_overview">Overview</h3>
<div class="paragraph">
<p>In this chapter, we provide an overview of the Virgo for Apache Tomcat focusing
on what it is, what benefits it provides to developers and administrators,
and why you should use it.</p>
</div>
<div class="paragraph">
<p><a id="introduction-what"></a></p>
</div>
</div>
<div class="sect2">
<h3 id="_what_is_the_virgo_for_apache_tomcat">What is the Virgo for Apache Tomcat?</h3>
<div class="paragraph">
<p>The Virgo for Apache Tomcat, or VTS for short, is the runtime portion of the Eclipse Virgo.
It is a lightweight, modular, OSGi-based runtime that provides a complete packaged solution for developing,
deploying, and managing enterprise applications.
By leveraging several best-of-breed technologies and improving upon
them, the VTS offers a compelling solution to develop and deploy
enterprise applications.</p>
</div>
<div class="paragraph">
<p><a id="introduction-constituents"></a></p>
</div>
<div class="sect3">
<h4 id="_what_makes_up_the_virgo_for_apache_tomcat">What Makes up the Virgo for Apache Tomcat?</h4>
<div class="paragraph">
<p>The Virgo for Apache Tomcat is built on top of the following core technologies:</p>
</div>
<div class="ulist">
<ul>
<li>
<p><a href="https://projects.spring.io/spring-framework/">Spring Framework</a>, obviously!</p>
</li>
<li>
<p><a href="http://tomcat.apache.org/">Tomcat</a> as the web container.</p>
</li>
<li>
<p><a href="http://www.osgi.org/Specifications/HomePage">OSGi R4.3</a>.</p>
</li>
<li>
<p><a href="http://www.eclipse.org/equinox/">Equinox</a> as the OSGi implementation.</p>
</li>
<li>
<p><a href="https://eclipse.org/gemini/blueprint/">Gemini Blueprint</a> for working with OSGi in a Spring application.</p>
</li>
<li>
<p><a href="http://www.eclipse.org/virgo/documentation/virgo-documentation-3.6.4.RELEASE/docs/virgo-tooling-guide/html/index.html">Tooling Guide</a> for developing applications.</p>
</li>
</ul>
</div>
<div class="paragraph">
<p>Note, however, that the Virgo for Apache Tomcat isn&#8217;t just a combination
of these technologies. Rather, it integrates and extends these
technologies to provide many features essential for developing,
deploying, and managing today&#8217;s enterprise Java applications.</p>
</div>
<div class="paragraph">
<p>The following diagram presents a high-level overview of the VTS&#8217;s architecture.</p>
</div>
<div class="paragraph">
<p><span class="image"><img src="assets/images/introduction-architecture.png" alt="introduction architecture"></span></p>
</div>
<div class="paragraph">
<p>At the heart of the Virgo for Apache Tomcat is the Virgo Kernel or VK.
The VK is an OSGi-based kernel that takes full advantage of the modularity
and versioning of the OSGi platform. The VK builds on a base version of Virgo Nano or VN and extends its capabilities for
provisioning and library management, as well as providing core functionality for the VTS. The VN maintains a minimal
runtime footprint and startup time. It builds on top of a pure Equinox, extending it with more sophisticated diagnostics and supportability functionality.
The VN supports full p2 provisioning. This feature is not included in the Virgo Nano Base that the VK is built on.</p>
</div>
<div class="paragraph">
<p>To maintain a minimal runtime footprint, OSGi bundles are installed on demand by the
VN. On subsequent restarts these core bundles are warm-started thus reducing the startup time. This allows for an application to be installed
into a running VTS and for its dependencies to be satisfied from an external repository. Not only
does this remove the need to manually install all your application dependencies, which would be tedious, but it also keeps memory usage to a minimum.</p>
</div>
<div class="paragraph">
<p>As shown in the figure, VK runs on top of VN that extends Equinox within a standard Java
Virtual Machine. Above the VK further layers contribute functionality
to the VTS. Such as management and web application support.</p>
</div>
<div class="paragraph">
<p>Version 3.7.0.RELEASE of the Virgo for Apache Tomcat supports <strong>bundle</strong>,
<strong>plan</strong>, <strong>PAR</strong>, <strong>configuration</strong>,
<strong>Web Application Bundle (WAB)</strong>, and <strong>WAR</strong> artifacts, which enable
you to build sophisticated web applications. This includes support for
standard Java EE WARs, "shared library" WARs, and "shared services" WARs, each of
which will be covered in greater detail in <a href="#architecture">[architecture]</a>.</p>
</div>
<div class="admonitionblock important">
<table>
<tr>
<td class="icon">
<div class="title">Important</div>
</td>
<td class="content">
<div class="paragraph">
<p>The Virgo Nano has a different provisioning system which isn&#8217;t included in the Virgo Nano Base on which the
VK and the VTS are built.</p>
</div>
</td>
</tr>
</table>
</div>
<div class="paragraph">
<p>Version 3.7.0.RELEASE of the Virgo Nano supports <strong>bundle</strong>,
<strong>p2 feature</strong>, <strong>Web Application Bundle (WAB)</strong>, and <strong>WAR</strong> artifacts, which enable
you to build sophisticated web applications too, taking full advantage of p2&#8217;s dependency resolution, automated download and fail-early mechanics.
The Virgo Nano does NOT support <strong>plan</strong>, <strong>PAR</strong> or <strong>configuration</strong> artifacts.
New <strong>features</strong> are provisioned via <strong>update sites</strong> or <strong>p2 repositories</strong>.
Brief overview of p2 and it&#8217;s mechanics is available on <a href="http://bkapukaranov.wordpress.com/2011/07/12/rt-meets-p2/">this blog</a>.
The VN&#8217;s default web container implementation is Gemini Web.</p>
</div>
<div class="paragraph">
<p><a id="introduction-why"></a></p>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_why_the_virgo_for_apache_tomcat">Why the Virgo for Apache Tomcat?</h3>
<div class="paragraph">
<p>You could deploy a web application in a stand-alone servlet engine or application server.
Or you could even deploy directly in an OSGi container such as Equinox. However,
deploying in the Virgo for Apache Tomcat offers a number of key benefits that make it both more
appealing and more suitable for enterprise application development.</p>
</div>
<div class="paragraph">
<p><a id="introduction-unified-deployment"></a></p>
</div>
<div class="sect3">
<h4 id="_deployment_options_and_migration_paths">Deployment Options and Migration Paths</h4>
<div class="paragraph">
<p>While many applications deployed in the Virgo for Apache Tomcat will take advantage
of OSGi capabilities, not all applications need such sophistication.
For example, development teams may initially choose to continue packaging
existing web applications as standard WAR files and then gradually migrate
toward a fully OSGi-based packaging and deployment model. The Virgo for Apache Tomcat
makes such migrations easy for developers by supporting multiple packaging
and deployment formats. These formats and migration strategies are discussed
in greater detail in <a href="#migrating-to-osgi">[migrating-to-osgi]</a> and
<a href="#formtags-case-study">[formtags-case-study]</a>.</p>
</div>
<div class="paragraph">
<p><a id="introduction-simplified-deployment"></a></p>
</div>
</div>
<div class="sect3">
<h4 id="_simplified_development_and_deployment_of_osgi_based_applications">Simplified Development and Deployment of OSGi-based Applications</h4>
<div class="paragraph">
<p>Prior to the release of the Virgo for Apache Tomcat, developing and deploying OSGi
applications involved inherent complexity such as:</p>
</div>
<div class="ulist">
<ul>
<li>
<p><strong>Obtaining OSGi bundles for popular Java libraries:</strong>
For optimal benefits, every technology you use in an OSGi application must
be packaged as OSGi bundles. Sometimes, this involves manually converting
JAR files into bundles and making sure that any libraries needed by those
bundles are also available as OSGi bundles. The <a href="http://www.eclipse.org/ebr">EBR</a> is a good source of
popular pre-bundled libraries.</p>
</li>
<li>
<p><strong>Package management complexity:</strong>
OSGi bundles use other bundles through <code>Import-Package</code> manifest headers.
Many applications use a set of common technologies (e.g., an ORM solution,
a web framework, etc.). Combining these two characteristics leads to duplicated
configuration in the form of repeated and verbose <code>Import-Package</code> statements.</p>
</li>
<li>
<p><strong>Lack of application-level isolation:</strong>
In OSGi everything is a bundle, and all bundles share the same OSGi Service Registry.
To highlight how conflicts can arise between applications and their services in this
shared service registry, consider the following scenarios.</p>
<div class="ulist">
<ul>
<li>
<p>Application <code>A</code> is comprised of bundles <code>B</code> and <code>C</code>.
In a standard OSGi environment, if you attempt to install two instances of the same
version of application <code>A</code> (i.e., two sets of bundles <code>B</code> and
<code>C</code>), a clash will occur, because you cannot deploy multiple bundles with
the same <code>Bundle-SymbolicName</code> and <code>Bundle-Version</code> combination.</p>
</li>
<li>
<p>Application <code>A1</code> is comprised of bundles <code>B1</code> and <code>C1</code>.
Similarly, application <code>A2</code> is comprised of bundles <code>B2</code> and <code>C2</code>.
Each bundle has a unique combination of <code>Bundle-SymbolicName</code> and <code>Bundle-Version</code>.
Bundles <code>B1</code> and <code>B2</code> both export service <code>S</code> which
is imported by both <code>C1</code> and <code>C2</code>. In contrast to the previous
example, there is no conflict resulting from duplicate
<code>Bundle-SymbolicName</code>/<code>Bundle-Version</code> combinations; however,
there is a clash for the exported service <code>S</code>.
Which service <code>S</code> will bundles <code>C1</code> and <code>C2</code> end up
using once they are installed?
Assuming bundles <code>B1</code> and <code>C1</code> are intended to work together,
you would not want bundle <code>C1</code> to get a reference to service <code>S</code>
from bundle <code>B2</code>, because it is installed in a different logical application.
On the contrary, you typically want bundle <code>C1</code> to get a reference to
service <code>S</code> exported by bundle <code>B1</code>, but in a standard OSGi environment
this may not be the case.</p>
</li>
</ul>
</div>
</li>
</ul>
</div>
<div class="paragraph">
<p>Furthermore, since standard OSGi does not define a notion of an application as a set of bundles,
you cannot deploy or undeploy an application and its constituent bundles as a single unit.</p>
</div>
<div class="paragraph">
<p>The Virgo for Apache Tomcat introduces a number of features to solve these issues:</p>
</div>
<div class="ulist">
<ul>
<li>
<p>A full set of OSGi bundles for many popular Java libraries to get you
started quickly with creating OSGi applications.</p>
</li>
<li>
<p>An OSGi library concept that obviates the need to
duplicate verbose <code>Import-Package</code> statements.</p>
</li>
<li>
<p>The PAR packaging format which offers
application-level isolation and deployment.</p>
</li>
<li>
<p>The concept of a plan, which is an XML file that lists a collection of bundles that Virgo for Apache Tomcat should load together as a single application. Conceptually, plans are very like PARs, except that a plan describes the contents of the application rather than a PAR that actually contains them.</p>
</li>
</ul>
</div>
<div class="paragraph">
<p><a id="introduction-diagnostics"></a></p>
</div>
</div>
<div class="sect3">
<h4 id="_enhanced_diagnostics_during_deployment_and_in_production">Enhanced Diagnostics During Deployment and in Production</h4>
<div class="paragraph">
<p>Identifying why an application won&#8217;t deploy or which particular library
dependencies are unsatisfied is the cause of many headaches!
Similarly, production time errors that don&#8217;t identify the root cause are
all too familiar to Java developers. The VTS was designed from the
ground up to enable tracing and First Failure Data Capture (FFDC) that
empower developers with precise information at the point of failure to
fix the problem quickly.</p>
</div>
</div>
</div>
</div>
</div>
</div>
<div id="footer">
<div id="footer-text">
Last updated 2017-02-23 21:06:43 +01:00
</div>
</div>
</body>
</html>