Added: tinkerpop/site/docs/3.2.6-SNAPSHOT/recipes/index.html URL: http://svn.apache.org/viewvc/tinkerpop/site/docs/3.2.6-SNAPSHOT/recipes/index.html?rev=1799018&view=auto ============================================================================== --- tinkerpop/site/docs/3.2.6-SNAPSHOT/recipes/index.html (added) +++ tinkerpop/site/docs/3.2.6-SNAPSHOT/recipes/index.html Sat Jun 17 18:56:29 2017 @@ -0,0 +1,3621 @@ +<!DOCTYPE html> +<html lang="en"> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> +<meta name="generator" content="Asciidoctor 0.1.4"> +<meta name="viewport" content="width=device-width, initial-scale=1.0"> +<title>Recipes</title> +<style> +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +/*! normalize.css v2.1.2 | MIT License | git.io/normalize */ +/* ========================================================================== HTML5 display definitions ========================================================================== */ +/** Correct `block` display not defined in IE 8/9. */ +@import url(http://cdnjs.cloudflare.com/ajax/libs/font-awesome/3.2.1/css/font-awesome.css); +article, aside, details, figcaption, figure, footer, header, hgroup, main, nav, section, summary { display: block; } + +/** Correct `inline-block` display not defined in IE 8/9. */ +audio, canvas, video { display: inline-block; } + +/** Prevent modern browsers from displaying `audio` without controls. Remove excess height in iOS 5 devices. */ +audio:not([controls]) { display: none; height: 0; } + +/** Address `[hidden]` styling not present in IE 8/9. Hide the `template` element in IE, Safari, and Firefox < 22. */ +[hidden], template { display: none; } + +script { display: none !important; } + +/* ========================================================================== Base ========================================================================== */ +/** 1. Set default font family to sans-serif. 2. Prevent iOS text size adjust after orientation change, without disabling user zoom. */ +html { font-family: sans-serif; /* 1 */ -ms-text-size-adjust: 100%; /* 2 */ -webkit-text-size-adjust: 100%; /* 2 */ } + +/** Remove default margin. */ +body { margin: 0; } + +/* ========================================================================== Links ========================================================================== */ +/** Remove the gray background color from active links in IE 10. */ +a { background: transparent; } + +/** Address `outline` inconsistency between Chrome and other browsers. */ +a:focus { outline: thin dotted; } + +/** Improve readability when focused and also mouse hovered in all browsers. */ +a:active, a:hover { outline: 0; } + +/* ========================================================================== Typography ========================================================================== */ +/** Address variable `h1` font-size and margin within `section` and `article` contexts in Firefox 4+, Safari 5, and Chrome. */ +h1 { font-size: 2em; margin: 0.67em 0; } + +/** Address styling not present in IE 8/9, Safari 5, and Chrome. */ +abbr[title] { border-bottom: 1px dotted; } + +/** Address style set to `bolder` in Firefox 4+, Safari 5, and Chrome. */ +b, strong { font-weight: bold; } + +/** Address styling not present in Safari 5 and Chrome. */ +dfn { font-style: italic; } + +/** Address differences between Firefox and other browsers. */ +hr { -moz-box-sizing: content-box; box-sizing: content-box; height: 0; } + +/** Address styling not present in IE 8/9. */ +mark { background: #ff0; color: #000; } + +/** Correct font family set oddly in Safari 5 and Chrome. */ +code, kbd, pre, samp { font-family: monospace, serif; font-size: 1em; } + +/** Improve readability of pre-formatted text in all browsers. */ +pre { white-space: pre-wrap; } + +/** Set consistent quote types. */ +q { quotes: "\201C" "\201D" "\2018" "\2019"; } + +/** Address inconsistent and variable font size in all browsers. */ +small { font-size: 80%; } + +/** Prevent `sub` and `sup` affecting `line-height` in all browsers. */ +sub, sup { font-size: 75%; line-height: 0; position: relative; vertical-align: baseline; } + +sup { top: -0.5em; } + +sub { bottom: -0.25em; } + +/* ========================================================================== Embedded content ========================================================================== */ +/** Remove border when inside `a` element in IE 8/9. */ +img { border: 0; } + +/** Correct overflow displayed oddly in IE 9. */ +svg:not(:root) { overflow: hidden; } + +/* ========================================================================== Figures ========================================================================== */ +/** Address margin not present in IE 8/9 and Safari 5. */ +figure { margin: 0; } + +/* ========================================================================== Forms ========================================================================== */ +/** Define consistent border, margin, and padding. */ +fieldset { border: 1px solid #c0c0c0; margin: 0 2px; padding: 0.35em 0.625em 0.75em; } + +/** 1. 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Avoid the WebKit bug in Android 4.0.* where (2) destroys native `audio` and `video` controls. 2. Correct inability to style clickable `input` types in iOS. 3. Improve usability and consistency of cursor style between image-type `input` and others. */ +button, html input[type="button"], input[type="reset"], input[type="submit"] { -webkit-appearance: button; /* 2 */ cursor: pointer; /* 3 */ } + +/** Re-set default cursor for disabled elements. */ +button[disabled], html input[disabled] { cursor: default; } + +/** 1. Address box sizing set to `content-box` in IE 8/9. 2. Remove excess padding in IE 8/9. */ +input[type="checkbox"], input[type="radio"] { box-sizing: border-box; /* 1 */ padding: 0; /* 2 */ } + +/** 1. Address `appearance` set to `searchfield` in Safari 5 and Chrome. 2. Address `box-sizing` set to `border-box` in Safari 5 and Chrome (include `-moz` to future-proof). */ +input[type="search"] { -webkit-appearance: textfield; /* 1 */ -moz-box-sizing: content-box; -webkit-box-sizing: content-box; /* 2 */ box-sizing: content-box; } + +/** Remove inner padding and search cancel button in Safari 5 and Chrome on OS X. */ +input[type="search"]::-webkit-search-cancel-button, input[type="search"]::-webkit-search-decoration { -webkit-appearance: none; } + +/** Remove inner padding and border in Firefox 4+. */ +button::-moz-focus-inner, input::-moz-focus-inner { border: 0; padding: 0; } + +/** 1. Remove default vertical scrollbar in IE 8/9. 2. Improve readability and alignment in all browsers. */ +textarea { overflow: auto; /* 1 */ vertical-align: top; /* 2 */ } + +/* ========================================================================== Tables ========================================================================== */ +/** Remove most spacing between table cells. */ +table { border-collapse: collapse; border-spacing: 0; } + +meta.foundation-mq-small { font-family: "only screen and (min-width: 768px)"; width: 768px; } + +meta.foundation-mq-medium { font-family: "only screen and (min-width:1280px)"; width: 1280px; } + +meta.foundation-mq-large { font-family: "only screen and (min-width:1440px)"; width: 1440px; } + +*, *:before, *:after { -moz-box-sizing: border-box; -webkit-box-sizing: border-box; box-sizing: border-box; } + +html, body { font-size: 100%; } + +body { background: white; color: #222222; padding: 0; margin: 0; font-family: "Helvetica Neue", "Helvetica", Helvetica, Arial, sans-serif; font-weight: normal; 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; } + +#map_canvas img, #map_canvas embed, #map_canvas object, .map_canvas img, .map_canvas embed, .map_canvas object { max-width: none !important; } + +.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; } + +.antialiased, body { -webkit-font-smoothing: antialiased; } + +img { display: inline-block; vertical-align: middle; } + +textarea { height: auto; min-height: 50px; } + +select { width: 100%; } + +p.lead, .paragraph.lead > p, #preamble > .sectionbody > .paragraph:first-of-type p { font-size: 1.21875em; line-height: 1.6; } + +.subheader, #content #toctitle, .admonitionblock td.content > .title, .exampleblock > .title, .imageblock > .title, .listingblock > .title, .literalblock > .title, .mathblock > .title, .openblock > .title, .paragraph > .title, .quoteblock > .title, .sidebarblock > .title, .tableblock > .title, .verseblock > .title, .videoblock > .title, .dlist > .title, .olist > .title, .ulist > .title, .qlist > .title, .hdlist > .title, .tableblock > caption { line-height: 1.4; color: #6c818f; font-weight: 300; margin-top: 0.2em; margin-bottom: 0.5em; } + +/* Typography resets */ +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; } + +/* Default Link Styles */ +a { color: #444444; text-decoration: underline; line-height: inherit; } +a:hover, a:focus { color: #111111; } +a img { border: none; } + +/* Default paragraph styles */ +p { font-family: inherit; font-weight: normal; font-size: 1em; line-height: 1.5; margin-bottom: 1.25em; text-rendering: optimizeLegibility; } +p aside { font-size: 0.875em; line-height: 1.35; font-style: italic; } + +/* Default header styles */ +h1, h2, h3, #toctitle, .sidebarblock > .content > .title, h4, h5, h6 { font-family: ff-meta-web-pro-1, ff-meta-web-pro-2, Arial, "Helvetica Neue", sans-serif; font-weight: bold; font-style: normal; color: #465158; text-rendering: optimizeLegibility; margin-top: 1em; margin-bottom: 0.5em; line-height: 1.2125em; } +h1 small, h2 small, h3 small, #toctitle small, .sidebarblock > .content > .title small, h4 small, h5 small, h6 small { font-size: 60%; color: #909ea7; line-height: 0; } + +h1 { font-size: 2.125em; } + +h2 { font-size: 1.6875em; } + +h3, #toctitle, .sidebarblock > .content > .title { font-size: 1.375em; } + +h4 { font-size: 1.125em; } + +h5 { font-size: 1.125em; } + +h6 { font-size: 1em; } + +hr { border: solid #dddddd; border-width: 1px 0 0; clear: both; margin: 1.25em 0 1.1875em; height: 0; } + +/* Helpful Typography Defaults */ +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: "Consolas", "Deja Vu Sans Mono", "Bitstream Vera Sans Mono", monospace; font-weight: normal; color: #444444; } + +/* Lists */ +ul, ol, dl { font-size: 1em; line-height: 1.5; margin-bottom: 1.25em; list-style-position: outside; font-family: inherit; } + +ul, ol { margin-left: 0; } +ul.no-bullet, ol.no-bullet { margin-left: 0; } + +/* Unordered Lists */ +ul li ul, ul li ol { margin-left: 1.25em; margin-bottom: 0; font-size: 1em; /* Override nested font-size change */ } +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; } + +/* Ordered Lists */ +ol li ul, ol li ol { margin-left: 1.25em; margin-bottom: 0; } + +/* Definition Lists */ +dl dt { margin-bottom: 0.3em; font-weight: bold; } +dl dd { margin-bottom: 0.75em; } + +/* Abbreviations */ +abbr, acronym { text-transform: uppercase; font-size: 90%; color: black; border-bottom: 1px dotted #dddddd; cursor: help; } + +abbr { text-transform: none; } + +/* Blockquotes */ +blockquote { margin: 0 0 1.25em; padding: 0.5625em 1.25em 0 1.1875em; border-left: 1px solid #dddddd; } +blockquote cite { display: block; font-size: 0.8125em; color: #748590; } +blockquote cite:before { content: "\2014 \0020"; } +blockquote cite a, blockquote cite a:visited { color: #748590; } + +blockquote, blockquote p { line-height: 1.5; color: #909ea7; } + +/* Microformats */ +.vcard { display: inline-block; margin: 0 0 1.25em 0; border: 1px solid #dddddd; padding: 0.625em 0.75em; } +.vcard li { margin: 0; display: block; } +.vcard .fn { font-weight: bold; font-size: 0.9375em; } + +.vevent .summary { font-weight: bold; } +.vevent abbr { cursor: auto; text-decoration: none; font-weight: bold; border: none; padding: 0 0.0625em; } + +@media only screen and (min-width: 768px) { h1, h2, h3, #toctitle, .sidebarblock > .content > .title, h4, h5, h6 { line-height: 1.4; } + h1 { font-size: 2.75em; } + h2 { font-size: 2.3125em; } + h3, #toctitle, .sidebarblock > .content > .title { font-size: 1.6875em; } + h4 { font-size: 1.4375em; } } +/* Print styles. Inlined to avoid required HTTP connection: www.phpied.com/delay-loading-your-print-css/ Credit to Paul Irish and HTML5 Boilerplate (html5boilerplate.com) +*/ +.print-only { display: none !important; } + +@media print { * { background: transparent !important; color: #000 !important; /* Black prints faster: h5bp.com/s */ box-shadow: none !important; text-shadow: none !important; } + a, a:visited { text-decoration: underline; } + a[href]:after { content: " (" attr(href) ")"; } + abbr[title]:after { content: " (" attr(title) ")"; } + .ir a:after, a[href^="javascript:"]:after, a[href^="#"]:after { content: ""; } + pre, blockquote { border: 1px solid #999; page-break-inside: avoid; } + thead { display: table-header-group; /* h5bp.com/t */ } + tr, img { page-break-inside: avoid; } + img { max-width: 100% !important; } + @page { margin: 0.5cm; } + p, h2, h3, #toctitle, .sidebarblock > .content > .title { orphans: 3; widows: 3; } + h2, h3, #toctitle, .sidebarblock > .content > .title { page-break-after: avoid; } + .hide-on-print { display: none !important; } + .print-only { display: block !important; } + .hide-for-print { display: none !important; } + .show-for-print { display: inherit !important; } } +/* Tables */ +table { background: white; margin-bottom: 1.25em; border: solid 0 #dddddd; } +table thead, table tfoot { background: none; font-weight: bold; } +table thead tr th, table thead tr td, table tfoot tr th, table tfoot tr td { padding: 1px 8px 1px 5px; font-size: 1em; color: #222222; text-align: left; } +table tr th, table tr td { padding: 1px 8px 1px 5px; font-size: 1em; color: #222222; } +table tr.even, table tr.alt, table tr:nth-of-type(even) { background: none; } +table thead tr th, table tfoot tr th, table tbody tr td, table tr td, table tfoot tr td { display: table-cell; line-height: 1.5; } + +.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: 0.95em; padding: 0; white-space: nowrap; background-color: #f2f2f2; border: 0 solid #dddddd; -webkit-border-radius: 6px; border-radius: 6px; text-shadow: none; } + +pre, pre > code { line-height: 1.2; color: inherit; font-family: "Consolas", "Deja Vu Sans Mono", "Bitstream Vera Sans Mono", monospace; font-weight: normal; } + +.keyseq { color: #333333; } + +kbd:not(.keyseq) { display: inline-block; color: black; font-size: 0.75em; line-height: 1.4; background-color: #F7F7F7; border: 1px solid #ccc; -webkit-border-radius: 3px; border-radius: 3px; -webkit-box-shadow: 0 1px 0 rgba(0, 0, 0, 0.2), 0 0 0 2px white inset; box-shadow: 0 1px 0 rgba(0, 0, 0, 0.2), 0 0 0 2px white inset; margin: -0.15em 0.15em 0 0.15em; padding: 0.2em 0.6em 0.2em 0.5em; vertical-align: middle; white-space: nowrap; } + +.keyseq kbd:first-child { margin-left: 0; } + +.keyseq kbd:last-child { margin-right: 0; } + +.menuseq, .menu { color: black; } + +b.button:before, b.button:after { position: relative; top: -1px; font-weight: normal; } + +b.button:before { content: "["; padding: 0 3px 0 2px; } + +b.button:after { content: "]"; padding: 0 2px 0 3px; } + +p a > code:hover { color: #373737; } + +#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: 0.9375em; padding-right: 0.9375em; } +#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; } + +#header { margin-bottom: 2.5em; } +#header > h1 { color: #111111; font-weight: bold; border-bottom: 1px solid #dddddd; margin-bottom: -28px; padding-bottom: 32px; } +#header span { color: #909ea7; } +#header #revnumber { text-transform: capitalize; } +#header br { display: none; } +#header br + span { padding-left: 3px; } +#header br + span:before { content: "\2013 \0020"; } +#header br + span.author { padding-left: 0; } +#header br + span.author:before { content: ", "; } + +#toc { border-bottom: 1px solid #dddddd; padding-bottom: 1.25em; } +#toc > ul { margin-left: 0.25em; } +#toc ul.sectlevel0 > li > a { font-style: italic; } +#toc ul.sectlevel0 ul.sectlevel1 { margin-left: 0; margin-top: 0.5em; margin-bottom: 0.5em; } +#toc ul { list-style-type: none; } + +#toctitle { color: #6c818f; } + +@media only screen and (min-width: 768px) { body.toc2 { padding-left: 15em; padding-right: 0; } + #toc.toc2 { position: fixed; width: 15em; left: 0; top: 0; border-right: 1px solid #dddddd; border-bottom: 0; z-index: 1000; padding: 1em; height: 100%; overflow: auto; } + #toc.toc2 #toctitle { margin-top: 0; font-size: 1.2em; } + #toc.toc2 > ul { font-size: .90em; } + #toc.toc2 ul ul { margin-left: 0; padding-left: 1em; } + #toc.toc2 ul.sectlevel0 ul.sectlevel1 { padding-left: 0; margin-top: 0.5em; margin-bottom: 0.5em; } + body.toc2.toc-right { padding-left: 0; padding-right: 15em; } + body.toc2.toc-right #toc.toc2 { border-right: 0; border-left: 1px solid #dddddd; 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: 0.95em; } + #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: #d9d9d9; margin-bottom: 1.25em; padding: 1.25em; background: #f2f2f2; border-width: 0; -webkit-border-radius: 6px; border-radius: 6px; } +#content #toc > :first-child { margin-top: 0; } +#content #toc > :last-child { margin-bottom: 0; } +#content #toc a { text-decoration: none; } + +#content #toctitle { font-weight: bold; font-family: ff-meta-web-pro-1, ff-meta-web-pro-2, Arial, "Helvetica Neue", sans-serif; font-size: 1em; padding-left: 0.125em; } + +#footer { max-width: 100%; background-color: black; padding: 1.25em; } + +#footer-text { color: white; line-height: 1.35; } + +.sect1 { padding-bottom: 1.25em; } + +.sect1 + .sect1 { border-top: 1px solid #dddddd; } + +#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; width: 1em; margin-left: -1em; display: block; text-decoration: none; visibility: hidden; text-align: center; font-weight: normal; } +#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; vertical-align: text-top; display: block; margin-top: 0.05em; } +#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: #465158; 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: #3b444a; } + +.imageblock, .literalblock, .listingblock, .mathblock, .verseblock, .videoblock { margin-bottom: 1.25em; } + +.admonitionblock td.content > .title, .exampleblock > .title, .imageblock > .title, .listingblock > .title, .literalblock > .title, .mathblock > .title, .openblock > .title, .paragraph > .title, .quoteblock > .title, .sidebarblock > .title, .tableblock > .title, .verseblock > .title, .videoblock > .title, .dlist > .title, .olist > .title, .ulist > .title, .qlist > .title, .hdlist > .title { text-align: left; font-weight: bold; } + +.tableblock > caption { text-align: left; font-weight: bold; white-space: nowrap; overflow: visible; max-width: 0; } + +table.tableblock #preamble > .sectionbody > .paragraph:first-of-type p { font-size: inherit; } + +.admonitionblock > table { 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; text-transform: uppercase; } +.admonitionblock > table td.content { padding-left: 1.125em; padding-right: 1.25em; border-left: 1px solid #dddddd; color: #909ea7; } +.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: white; -webkit-border-radius: 6px; border-radius: 6px; } +.exampleblock > .content > :first-child { margin-top: 0; } +.exampleblock > .content > :last-child { margin-bottom: 0; } +.exampleblock > .content h1, .exampleblock > .content h2, .exampleblock > .content h3, .exampleblock > .content #toctitle, .sidebarblock.exampleblock > .content > .title, .exampleblock > .content h4, .exampleblock > .content h5, .exampleblock > .content h6, .exampleblock > .content p { color: #333333; } +.exampleblock > .content h1, .exampleblock > .content h2, .exampleblock > .content h3, .exampleblock > .content #toctitle, .sidebarblock.exampleblock > .content > .title, .exampleblock > .content h4, .exampleblock > .content h5, .exampleblock > .content h6 { line-height: 1; margin-bottom: 0.625em; } +.exampleblock > .content h1.subheader, .exampleblock > .content h2.subheader, .exampleblock > .content h3.subheader, .exampleblock > .content .subheader#toctitle, .sidebarblock.exampleblock > .content > .subheader.title, .exampleblock > .content h4.subheader, .exampleblock > .content h5.subheader, .exampleblock > .content h6.subheader { line-height: 1.4; } + +.exampleblock.result > .content { -webkit-box-shadow: 0 1px 8px #d9d9d9; box-shadow: 0 1px 8px #d9d9d9; } + +.sidebarblock { border-style: solid; border-width: 1px; border-color: #d9d9d9; margin-bottom: 1.25em; padding: 1.25em; background: #f2f2f2; -webkit-border-radius: 6px; border-radius: 6px; } +.sidebarblock > :first-child { margin-top: 0; } +.sidebarblock > :last-child { margin-bottom: 0; } +.sidebarblock h1, .sidebarblock h2, .sidebarblock h3, .sidebarblock #toctitle, .sidebarblock > .content > .title, .sidebarblock h4, .sidebarblock h5, .sidebarblock h6, .sidebarblock p { color: #333333; } +.sidebarblock h1, .sidebarblock h2, .sidebarblock h3, .sidebarblock #toctitle, .sidebarblock > .content > .title, .sidebarblock h4, .sidebarblock h5, .sidebarblock h6 { line-height: 1; margin-bottom: 0.625em; } +.sidebarblock h1.subheader, .sidebarblock h2.subheader, .sidebarblock h3.subheader, .sidebarblock .subheader#toctitle, .sidebarblock > .content > .subheader.title, .sidebarblock h4.subheader, .sidebarblock h5.subheader, .sidebarblock h6.subheader { line-height: 1.4; } +.sidebarblock > .content > .title { color: #6c818f; margin-top: 0; line-height: 1.5; } + +.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:not([class]), .listingblock pre:not([class]) { background: #eeeeee; } +.literalblock pre, .literalblock pre[class], .listingblock pre, .listingblock pre[class] { border-width: 1px; border-style: solid; border-color: #cccccc; -webkit-border-radius: 6px; border-radius: 6px; padding: 0.5em; word-wrap: break-word; } +.literalblock pre.nowrap, .literalblock pre[class].nowrap, .listingblock pre.nowrap, .listingblock pre[class].nowrap { overflow-x: auto; white-space: pre; word-wrap: normal; } +.literalblock pre > code, .literalblock pre[class] > code, .listingblock pre > code, .listingblock pre[class] > code { display: block; } +@media only screen { .literalblock pre, .literalblock pre[class], .listingblock pre, .listingblock pre[class] { font-size: 0.76em; } } +@media only screen and (min-width: 768px) { .literalblock pre, .literalblock pre[class], .listingblock pre, .listingblock pre[class] { font-size: 0.855em; } } +@media only screen and (min-width: 1280px) { .literalblock pre, .literalblock pre[class], .listingblock pre, .listingblock pre[class] { font-size: 0.95em; } } + +.listingblock pre.highlight { padding: 0; } +.listingblock pre.highlight > code { padding: 0.5em; } + +.listingblock > .content { position: relative; } + +.listingblock:hover code[class*=" language-"]:before { text-transform: uppercase; font-size: 0.9em; color: #999; position: absolute; top: 0.375em; right: 0.375em; } + +.listingblock:hover code.asciidoc:before { content: "asciidoc"; } +.listingblock:hover code.clojure:before { content: "clojure"; } +.listingblock:hover code.css:before { content: "css"; } +.listingblock:hover code.groovy:before { content: "groovy"; } +.listingblock:hover code.html:before { content: "html"; } +.listingblock:hover code.java:before { content: "java"; } +.listingblock:hover code.javascript:before { content: "javascript"; } +.listingblock:hover code.python:before { content: "python"; } +.listingblock:hover code.ruby:before { content: "ruby"; } +.listingblock:hover code.sass:before { content: "sass"; } +.listingblock:hover code.scss:before { content: "scss"; } +.listingblock:hover code.xml:before { content: "xml"; } +.listingblock:hover code.yaml:before { content: "yaml"; } + +.listingblock.terminal pre .command:before { content: attr(data-prompt); padding-right: 0.5em; color: #999; } + +.listingblock.terminal pre .command:not([data-prompt]):before { content: '$'; } + +table.pyhltable { border: 0; margin-bottom: 0; } + +table.pyhltable td { vertical-align: top; padding-top: 0; padding-bottom: 0; } + +table.pyhltable td.code { padding-left: .75em; padding-right: 0; } + +.highlight.pygments .lineno, table.pyhltable td:not(.code) { color: #999; padding-left: 0; padding-right: .5em; border-right: 1px solid #dddddd; } + +.highlight.pygments .lineno { display: inline-block; margin-right: .25em; } + +table.pyhltable .linenodiv { background-color: transparent !important; padding-right: 0 !important; } + +.quoteblock { margin: 0 0 1.25em; padding: 0.5625em 1.25em 0 1.1875em; border-left: 1px solid #dddddd; } +.quoteblock blockquote { margin: 0 0 1.25em 0; padding: 0 0 0.5625em 0; border: 0; } +.quoteblock blockquote > .paragraph:last-child p { margin-bottom: 0; } +.quoteblock .attribution { margin-top: -.25em; padding-bottom: 0.5625em; font-size: 0.8125em; color: #748590; } +.quoteblock .attribution br { display: none; } +.quoteblock .attribution cite { display: block; margin-bottom: 0.625em; } + +table thead th, table tfoot th { font-weight: bold; } + +table.tableblock.grid-all { border-collapse: separate; border-spacing: 1px; -webkit-border-radius: 6px; border-radius: 6px; border-top: 0 solid #dddddd; border-bottom: 0 solid #dddddd; } + +table.tableblock.frame-topbot, table.tableblock.frame-none { border-left: 0; border-right: 0; } + +table.tableblock.frame-sides, table.tableblock.frame-none { border-top: 0; border-bottom: 0; } + +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; } + +th.tableblock.halign-left, td.tableblock.halign-left { text-align: left; } + +th.tableblock.halign-right, td.tableblock.halign-right { text-align: right; } + +th.tableblock.halign-center, td.tableblock.halign-center { text-align: center; } + +th.tableblock.valign-top, td.tableblock.valign-top { vertical-align: top; } + +th.tableblock.valign-bottom, td.tableblock.valign-bottom { vertical-align: bottom; } + +th.tableblock.valign-middle, td.tableblock.valign-middle { vertical-align: middle; } + +tbody tr th { display: table-cell; line-height: 1.5; background: none; } + +tbody tr th, tbody tr th p, tfoot tr th, tfoot tr th p { color: #222222; font-weight: bold; } + +td > div.verse { white-space: pre; } + +ol { margin-left: 0.25em; } + +ul li ol { margin-left: 0; } + +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: 0.625em; } + +ul.unstyled, ol.unnumbered, ul.checklist, ul.none { list-style-type: none; } + +ul.unstyled, ol.unnumbered, ul.checklist { margin-left: 0.625em; } + +ul.checklist li > p:first-child > i[class^="icon-check"]:first-child, ul.checklist li > p:first-child > input[type="checkbox"]:first-child { margin-right: 0.25em; } + +ul.checklist li > p:first-child > input[type="checkbox"]:first-child { position: relative; top: 1px; } + +ul.inline { margin: 0 auto 0.625em 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: normal; 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 { padding-right: .75em; font-weight: bold; } + +td.hdlist1, td.hdlist2 { vertical-align: top; } + +.literalblock + .colist, .listingblock + .colist { margin-top: -0.5em; } + +.colist > table tr > td:first-of-type { padding: 0 .75em; line-height: 1; } +.colist > table tr > td:last-of-type { padding: 0.25em 0; } + +.qanda > ol > li > p > em:only-child { color: #373737; } + +.thumb, .th { line-height: 0; display: inline-block; border: solid 4px white; -webkit-box-shadow: 0 0 0 1px #dddddd; box-shadow: 0 0 0 1px #dddddd; } + +.imageblock.left, .imageblock[style*="float: left"] { margin: 0.25em 0.625em 1.25em 0; } +.imageblock.right, .imageblock[style*="float: right"] { margin: 0.25em 0 1.25em 0.625em; } +.imageblock > .title { margin-bottom: 0; } +.imageblock.thumb, .imageblock.th { border-width: 6px; } +.imageblock.thumb > .title, .imageblock.th > .title { padding: 0 0.125em; } + +.image.left, .image.right { margin-top: 0.25em; margin-bottom: 0.25em; display: inline-block; line-height: 0; } +.image.left { margin-right: 0.625em; } +.image.right { margin-left: 0.625em; } + +a.image { text-decoration: none; } + +span.footnote, span.footnoteref { vertical-align: super; font-size: 0.875em; } +span.footnote a, span.footnoteref a { text-decoration: none; } + +#footnotes { padding-top: 0.75em; padding-bottom: 0.75em; margin-bottom: 0.625em; } +#footnotes hr { width: 20%; min-width: 6.25em; margin: -.25em 0 .75em 0; border-width: 1px 0 0 0; } +#footnotes .footnote { padding: 0 0.375em; line-height: 1.3; font-size: 0.875em; margin-left: 1.2em; text-indent: -1.2em; 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: -0.625em; margin-bottom: 0; padding: 0.75em 0; } + +.gist .file-data > table { border: none; 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: black; } + +.black-background { background-color: black; } + +.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 > [class^="icon-"], span.icon > [class*=" icon-"] { cursor: default; } + +.admonitionblock td.icon [class^="icon-"]:before { font-size: 2.5em; text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); cursor: default; } +.admonitionblock td.icon .icon-note:before { content: "\f05a"; color: #444444; color: #333333; } +.admonitionblock td.icon .icon-tip:before { content: "\f0eb"; text-shadow: 1px 1px 2px rgba(155, 155, 0, 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 { display: inline-block; color: white !important; background-color: black; -webkit-border-radius: 100px; border-radius: 100px; text-align: center; width: 20px; height: 20px; font-size: 12px; font-weight: bold; line-height: 20px; font-family: Arial, sans-serif; font-style: normal; position: relative; top: -2px; letter-spacing: -1px; } +.conum * { color: white !important; } +.conum + b { display: none; } +.conum:after { content: attr(data-value); } +.conum:not([data-value]):empty { display: none; } + +.listingblock code { white-space: pre; overflow: auto; overflow-wrap: normal; /* needed for webkit browsers */ } + +#toc ul.sectlevel0 > li > a { font-style: normal; font-weight: bold; } + +h4 { color: #6c818f; } + +.literalblock > .content > pre, .listingblock > .content > pre { -webkit-border-radius: 6px; border-radius: 6px; margin-left: 2em; margin-right: 2em; } + +.admonitionblock { margin-left: 2em; margin-right: 2em; } +.admonitionblock > table { border: 1px solid #609060; border-top-width: 1.5em; background-color: #e9ffe9; border-collapse: separate; -webkit-border-radius: 0; border-radius: 0; } +.admonitionblock > table td.icon { padding-top: .5em; padding-bottom: .5em; } +.admonitionblock > table td.content { padding: .5em 1em; color: black; font-size: .9em; border-left: none; } + +.sidebarblock { background-color: #e8ecef; border-color: #ccc; } +.sidebarblock > .content > .title { color: #444444; } + +table.tableblock.grid-all { border-collapse: collapse; -webkit-border-radius: 0; border-radius: 0; } +table.tableblock.grid-all th.tableblock, table.tableblock.grid-all td.tableblock { border-bottom: 1px solid #aaa; } + +#footer { background-color: #465158; padding: 2em; } + +#footer-text { color: #eee; font-size: 0.8em; text-align: center; } +</style> +<style> +/* Foundation stylesheet for CodeRay (to match GitHub theme) | MIT License | http://foundation.zurb.com */ +table.CodeRay { border-collapse: collapse; padding: 2px; margin-bottom: 0; border: 0; background: transparent; } +table.CodeRay td { padding: 0 .5em; vertical-align: top; } +table.CodeRay td.line-numbers { text-align: right; color: #999; border-right: 1px solid #e5e5e5; padding-left: 0; } +span.line-numbers { border-right: 1px solid #E5E5E5; color: #999; display: inline-block; margin-right: 0.5em; padding-right: 0.5em; } +.CodeRay td.line-numbers strong, .CodeRay span.line-numbers strong { font-weight: normal; } +.CodeRay .debug { color: white !important; background: blue !important; } +.CodeRay .annotation { color: #007; } +.CodeRay .attribute-name { color: #f08; } +.CodeRay .attribute-value { color: #700; } +.CodeRay .binary { color: #509; } +.CodeRay .comment { color: #999; font-style: italic; } +.CodeRay .char { color: #04D; } +.CodeRay .char .content { color: #04D; } +.CodeRay .char .delimiter { color: #039; } +.CodeRay .class { color: #458; } +.CodeRay .complex { color: #A08; } +.CodeRay .constant { color: teal; } +.CodeRay .color { color: #0A0; } +.CodeRay .class-variable { color: #369; } +.CodeRay .decorator { color: #B0B; } +.CodeRay .definition { color: #099; } +.CodeRay .directive { color: #088; } +.CodeRay .delimiter { color: black; } +.CodeRay .doc { color: #970; } +.CodeRay .doctype { color: #34b; } +.CodeRay .doc-string { color: #D42; } +.CodeRay .escape { color: #666; } +.CodeRay .entity { color: #800; } +.CodeRay .error { color: #808; } +.CodeRay .exception { color: #C00; } +.CodeRay .filename { color: #099; } +.CodeRay .function { color: #900; } +.CodeRay .global-variable { color: teal; } +.CodeRay .hex { color: #058; } +.CodeRay .integer { color: #099; } +.CodeRay .include { color: #B44; } +.CodeRay .inline { color: black; } +.CodeRay .inline .inline { background: #ccc; } +.CodeRay .inline .inline .inline { background: #bbb; } +.CodeRay .inline .inline-delimiter { color: #D14; } +.CodeRay .inline-delimiter { color: #D14; } +.CodeRay .important { color: #f00; } +.CodeRay .interpreted { color: #B2B; } +.CodeRay .instance-variable { color: teal; } +.CodeRay .label { color: #970; } +.CodeRay .local-variable { color: #963; } +.CodeRay .octal { color: #40E; } +.CodeRay .predefined { color: #369; } +.CodeRay .preprocessor { color: #579; } +.CodeRay .pseudo-class { color: #00C; } +.CodeRay .predefined-type { color: #074; } +.CodeRay .reserved, .keyword { color: #000; } +.CodeRay .key { color: #808; } +.CodeRay .key .delimiter { color: #606; } +.CodeRay .key .char { color: #80f; } +.CodeRay .value { color: #088; } +.CodeRay .regexp { background-color: #fff0ff; } +.CodeRay .regexp .content { color: #808; } +.CodeRay .regexp .delimiter { color: #404; } +.CodeRay .regexp .modifier { color: #C2C; } +.CodeRay .regexp .function { color: #404; font-weight: bold; } +.CodeRay .string { color: #D20; } +.CodeRay .string .string { } +.CodeRay .string .string .string { background-color: #ffd0d0; } +.CodeRay .string .content { color: #D14; } +.CodeRay .string .char { color: #D14; } +.CodeRay .string .delimiter { color: #D14; } +.CodeRay .shell { color: #D14; } +.CodeRay .shell .content { } +.CodeRay .shell .delimiter { color: #D14; } +.CodeRay .symbol { color: #990073; } +.CodeRay .symbol .content { color: #A60; } +.CodeRay .symbol .delimiter { color: #630; } +.CodeRay .tag, .CodeRay .attribute-name { color: #070; } +.CodeRay .tag-special { color: #D70; } +.CodeRay .type { color: #339; } +.CodeRay .variable { color: #036; } +.CodeRay .insert { background: #afa; } +.CodeRay .delete { background: #faa; } +.CodeRay .change { color: #aaf; background: #007; } +.CodeRay .head { color: #f8f; background: #505; } +.CodeRay .insert .insert { color: #080; } +.CodeRay .delete .delete { color: #800; } +.CodeRay .change .change { color: #66f; } +.CodeRay .head .head { color: #f4f; } + +</style> +</head> +<body class="book toc2 toc-left"> +<div id="header"> +<div id="toc" class="toc2"> +<div id="toctitle">Table of Contents</div> +<ul class="sectlevel0"> +<li><a href="#_recipes">Recipes</a></li> +<li><a href="#_traversal_recipes">Traversal Recipes</a></li> +<li> +<ul class="sectlevel1"> +<li><a href="#between-vertices">Between Vertices</a></li> +<li><a href="#centrality">Centrality</a></li> +<li> +<ul class="sectlevel2"> +<li><a href="#degree-centrality">Degree Centrality</a></li> +<li><a href="#betweeness-centrality">Betweeness Centrality</a></li> +<li><a href="#closeness-centrality">Closeness Centrality</a></li> +<li><a href="#eigenvector-centrality">Eigenvector Centrality</a></li> +</ul> +</li> +<li><a href="#connected-components">Connected Components</a></li> +<li><a href="#cycle-detection">Cycle Detection</a></li> +<li><a href="#duplicate-edge">Duplicate Edge Detection</a></li> +<li><a href="#duplicate-vertex">Duplicate Vertex Detection</a></li> +<li><a href="#if-then-based-grouping">If-Then Based Grouping</a></li> +<li><a href="#pagination">Pagination</a></li> +<li><a href="#recommendation">Recommendation</a></li> +<li><a href="#shortest-path">Shortest Path</a></li> +<li><a href="#traversal-induced-values">Traversal Induced Values</a></li> +<li><a href="#tree">Tree</a></li> +<li> +<ul class="sectlevel2"> +<li><a href="#_lowest_common_ancestor">Lowest Common Ancestor</a></li> +<li><a href="#_maximum_depth">Maximum Depth</a></li> +<li><a href="#_time_based_indexing">Time-based Indexing</a></li> +</ul> +</li> +</ul> +</li> +<li><a href="#_implementation_recipes">Implementation Recipes</a></li> +<li> +<ul class="sectlevel1"> +<li><a href="#style-guide">Style Guide</a></li> +<li> +<ul class="sectlevel2"> +<li><a href="#_style_guide_rules">Style Guide Rules</a></li> +</ul> +</li> +<li><a href="#traversal-component-reuse">Traversal Component Reuse</a></li> +</ul> +</li> +<li><a href="#contributing">How to Contribute a Recipe</a></li> +<li><a href="#_appendix">Appendix</a></li> +</ul> +</div> +</div> +<div id="content"> +<div class="imageblock"> +<div class="content"> +<a class="image" href="http://tinkerpop.apache.org";><img src="../images/apache-tinkerpop-logo.png" alt="apache tinkerpop logo" width="500"></a> +</div> +</div> +<div class="paragraph"> +<p><strong>3.2.6-SNAPSHOT</strong></p> +</div> +<h1 id="_recipes" class="sect0">Recipes</h1> +<div class="paragraph"> +<p><span class="image" style="float: left"><img src="../images/gremlin-chef.png" alt="gremlin-chef" width="120"></span> All programming languages tend to have +<a href="https://en.wikipedia.org/wiki/Software_design_pattern";>patterns of usage</a> for commonly occurring problems. Gremlin +is not different in that respect. There are many commonly occurring traversal themes that have general applicability +to any graph. Gremlin Recipes present these common traversal patterns and methods of usage that will +provide some basic building blocks for virtually any graph in any domain.</p> +</div> +<div class="paragraph"> +<p>Recipes assume general familiarity with Gremlin and the TinkerPop stack. Be sure to have read the +<a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/tutorials/getting-started";>Getting Started</a> tutorial and the +<a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/tutorials/the-gremlin-console/";>The Gremlin Console</a> tutorial.</p> +</div> +<h1 id="_traversal_recipes" class="sect0">Traversal Recipes</h1> +<div class="sect1"> +<h2 id="between-vertices">Between Vertices</h2> +<div class="sectionbody"> +<div class="paragraph"> +<p>It is quite common to have a situation where there are two particular vertices of a graph and a need to execute some +traversal on the paths found between them. Consider the following examples using the modern toy graph:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="groovy language-groovy">gremlin> g.V(<span class="integer">1</span>).bothE() <span class="comment">//</span><b>(1)</b> +==>e[<span class="integer">9</span>][<span class="integer">1</span>-created-><span class="integer">3</span>] +==>e[<span class="integer">7</span>][<span class="integer">1</span>-knows-><span class="integer">2</span>] +==>e[<span class="integer">8</span>][<span class="integer">1</span>-knows-><span class="integer">4</span>] +gremlin> g.V(<span class="integer">1</span>).bothE().where(otherV().hasId(<span class="integer">2</span>)) <span class="comment">//</span><b>(2)</b> +==>e[<span class="integer">7</span>][<span class="integer">1</span>-knows-><span class="integer">2</span>] +gremlin> v1 = g.V(<span class="integer">1</span>).next();<span class="type">[]</span> +gremlin> v2 = g.V(<span class="integer">2</span>).next();<span class="type">[]</span> +gremlin> g.V(v1).bothE().where(otherV().is(v2)) <span class="comment">//</span><b>(3)</b> +==>e[<span class="integer">7</span>][<span class="integer">1</span>-knows-><span class="integer">2</span>] +gremlin> g.V(v1).outE().where(inV().is(v2)) <span class="comment">//</span><b>(4)</b> +==>e[<span class="integer">7</span>][<span class="integer">1</span>-knows-><span class="integer">2</span>] +gremlin> g.V(<span class="integer">1</span>).outE().where(inV().has(id, within(<span class="integer">2</span>,<span class="integer">3</span>))) <span class="comment">//</span><b>(5)</b> +==>e[<span class="integer">9</span>][<span class="integer">1</span>-created-><span class="integer">3</span>] +==>e[<span class="integer">7</span>][<span class="integer">1</span>-knows-><span class="integer">2</span>] +gremlin> g.V(<span class="integer">1</span>).out().where(__.in().hasId(<span class="integer">6</span>)) <span class="comment">//</span><b>(6)</b> +==>v[<span class="integer">3</span>]</code></pre> +</div> +</div> +<div class="colist arabic"> +<ol> +<li> +<p>There are three edges from the vertex with the identifier of "1".</p> +</li> +<li> +<p>Filter those three edges using the <code>where()</code> step using the identifier of the vertex returned by <code>otherV()</code> to +ensure it matches on the vertex of concern, which is the one with an identifier of "2".</p> +</li> +<li> +<p>Note that the same traversal will work if there are actual <code>Vertex</code> instances rather than just vertex identiers.</p> +</li> +<li> +<p>The vertex with identifier "1" has all outgoing edges, so it would also be acceptable to use the directional steps +of <code>outE()</code> and <code>inV()</code> since the schema allows it.</p> +</li> +<li> +<p>There is also no problem with filtering the terminating side of the traversal on multiple vertices, in this case, +vertices with identifiers "2" and "3".</p> +</li> +<li> +<p>There’s no reason why the same pattern of exclusion used for edges with <code>where()</code> can’t work for a vertex between +two vertices.</p> +</li> +</ol> +</div> +<div class="paragraph"> +<p>The basic pattern of using <code>where()</code> step to find the "other" known vertex can be applied in far more complex +scenarios. For one such example, consider the following traversal that finds all the paths between a group of defined +vertices:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="groovy language-groovy">gremlin> ids = [<span class="integer">2</span>,<span class="integer">4</span>,<span class="integer">6</span>].toArray() +==><span class="integer">2</span> +==><span class="integer">4</span> +==><span class="integer">6</span> +gremlin> g.V(ids).as(<span class="string"><span class="delimiter">"</span><span class="content">a</span><span class="delimiter">"</span></span>). + repeat(bothE().otherV().simplePath()).times(<span class="integer">5</span>).emit(hasId(within(ids))).as(<span class="string"><span class="delimiter">"</span><span class="content">b</span><span class="delimiter">"</span></span>). + filter(select(last,<span class="string"><span class="delimiter">"</span><span class="content">a</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">b</span><span class="delimiter">"</span></span>).by(id).where(<span class="string"><span class="delimiter">"</span><span class="content">a</span><span class="delimiter">"</span></span>, lt(<span class="string"><span class="delimiter">"</span><span class="content">b</span><span class="delimiter">"</span></span>))). + path().by().by(label) +==>[v[<span class="integer">2</span>],knows,v[<span class="integer">1</span>],knows,v[<span class="integer">4</span>]] +==>[v[<span class="integer">2</span>],knows,v[<span class="integer">1</span>],created,v[<span class="integer">3</span>],created,v[<span class="integer">4</span>]] +==>[v[<span class="integer">2</span>],knows,v[<span class="integer">1</span>],created,v[<span class="integer">3</span>],created,v[<span class="integer">6</span>]] +==>[v[<span class="integer">2</span>],knows,v[<span class="integer">1</span>],knows,v[<span class="integer">4</span>],created,v[<span class="integer">3</span>],created,v[<span class="integer">6</span>]] +==>[v[<span class="integer">4</span>],created,v[<span class="integer">3</span>],created,v[<span class="integer">6</span>]] +==>[v[<span class="integer">4</span>],knows,v[<span class="integer">1</span>],created,v[<span class="integer">3</span>],created,v[<span class="integer">6</span>]]</code></pre> +</div> +</div> +<div class="paragraph"> +<p>For another example, consider the following schema:</p> +</div> +<div class="paragraph"> +<p><span class="image"><img src="../images/recipe-job-schema.png" alt="recipe-job-schema" width="750"></span></p> +</div> +<div class="paragraph"> +<p>Assume that the goal is to find information about a known job and a known person. Specifically, the idea would be +to extract the known job, the company that created the job, the date it was created by the company and whether or not +the known person completed an application.</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="groovy language-groovy">gremlin> vBob = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">person</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">bob</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">0</span>] +gremlin> vStephen = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">person</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">stephen</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">2</span>] +gremlin> vBlueprintsInc = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">company</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">Blueprints, Inc</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">4</span>] +gremlin> vRexsterLlc = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">company</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">Rexster, LLC</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">6</span>] +gremlin> vBlueprintsJob1 = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">job</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">job1</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">8</span>] +gremlin> vBlueprintsJob2 = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">job</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">job2</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">10</span>] +gremlin> vBlueprintsJob3 = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">job</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">job3</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">12</span>] +gremlin> vRexsterJob1 = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">job</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">job4</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">14</span>] +gremlin> vAppBob1 = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">application</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">application1</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">16</span>] +gremlin> vAppBob2 = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">application</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">application2</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">18</span>] +gremlin> vAppStephen1 = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">application</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">application3</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">20</span>] +gremlin> vAppStephen2 = graph.addVertex(label, <span class="string"><span class="delimiter">"</span><span class="content">application</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">name</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">application4</span><span class="delimiter">"</span></span>) +==>v[<span class="integer">22</span>] +gremlin> vBob.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">completes</span><span class="delimiter">"</span></span>, vAppBob1) +==>e[<span class="integer">24</span>][<span class="integer">0</span>-completes-><span class="integer">16</span>] +gremlin> vBob.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">completes</span><span class="delimiter">"</span></span>, vAppBob2) +==>e[<span class="integer">25</span>][<span class="integer">0</span>-completes-><span class="integer">18</span>] +gremlin> vStephen.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">completes</span><span class="delimiter">"</span></span>, vAppStephen1) +==>e[<span class="integer">26</span>][<span class="integer">2</span>-completes-><span class="integer">20</span>] +gremlin> vStephen.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">completes</span><span class="delimiter">"</span></span>, vAppStephen2) +==>e[<span class="integer">27</span>][<span class="integer">2</span>-completes-><span class="integer">22</span>] +gremlin> vAppBob1.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">appliesTo</span><span class="delimiter">"</span></span>, vBlueprintsJob1) +==>e[<span class="integer">28</span>][<span class="integer">16</span>-appliesTo-><span class="integer">8</span>] +gremlin> vAppBob2.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">appliesTo</span><span class="delimiter">"</span></span>, vBlueprintsJob2) +==>e[<span class="integer">29</span>][<span class="integer">18</span>-appliesTo-><span class="integer">10</span>] +gremlin> vAppStephen1.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">appliesTo</span><span class="delimiter">"</span></span>, vRexsterJob1) +==>e[<span class="integer">30</span>][<span class="integer">20</span>-appliesTo-><span class="integer">14</span>] +gremlin> vAppStephen2.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">appliesTo</span><span class="delimiter">"</span></span>, vBlueprintsJob3) +==>e[<span class="integer">31</span>][<span class="integer">22</span>-appliesTo-><span class="integer">12</span>] +gremlin> vBlueprintsInc.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">created</span><span class="delimiter">"</span></span>, vBlueprintsJob1, <span class="string"><span class="delimiter">"</span><span class="content">creationDate</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">12/20/2015</span><span class="delimiter">"</span></span>) +==>e[<span class="integer">32</span>][<span class="integer">4</span>-created-><span class="integer">8</span>] +gremlin> vBlueprintsInc.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">created</span><span class="delimiter">"</span></span>, vBlueprintsJob2, <span class="string"><span class="delimiter">"</span><span class="content">creationDate</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">12/15/2015</span><span class="delimiter">"</span></span>) +==>e[<span class="integer">33</span>][<span class="integer">4</span>-created-><span class="integer">10</span>] +gremlin> vBlueprintsInc.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">created</span><span class="delimiter">"</span></span>, vBlueprintsJob3, <span class="string"><span class="delimiter">"</span><span class="content">creationDate</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">12/16/2015</span><span class="delimiter">"</span></span>) +==>e[<span class="integer">34</span>][<span class="integer">4</span>-created-><span class="integer">12</span>] +gremlin> vRexsterLlc.addEdge(<span class="string"><span class="delimiter">"</span><span class="content">created</span><span class="delimiter">"</span></span>, vRexsterJob1, <span class="string"><span class="delimiter">"</span><span class="content">creationDate</span><span class="delimiter">"</span></span>, <span class="string"><span class="delimiter">"</span><span class="content">12/18/2015</span><span class="delimiter">"</span></span>) +==>e[<span class="integer">35</span>][<span class="integer">6</span>-created-><span class="integer">14</span>] +gremlin> g.V(vRexsterJob1).as(<span class="string"><span class="delimiter">'</span><span class="content">job</span><span class="delimiter">'</span></span>). + inE(<span class="string"><span class="delimiter">'</span><span class="content">created</span><span class="delimiter">'</span></span>).as(<span class="string"><span class="delimiter">'</span><span class="content">created</span><span class="delimiter">'</span></span>). + outV().as(<span class="string"><span class="delimiter">'</span><span class="content">company</span><span class="delimiter">'</span></span>). + select(<span class="string"><span class="delimiter">'</span><span class="content">job</span><span class="delimiter">'</span></span>). + coalesce(__.in(<span class="string"><span class="delimiter">'</span><span class="content">appliesTo</span><span class="delimiter">'</span></span>).where(__.in(<span class="string"><span class="delimiter">'</span><span class="content">completes</span><span class="delimiter">'</span></span>).is(vStephen)), + constant(<span class="predefined-constant">false</span>)).as(<span class="string"><span class="delimiter">'</span><span class="content">application</span><span class="delimiter">'</span></span>). + select(<span class="string"><span class="delimiter">'</span><span class="content">job</span><span class="delimiter">'</span></span>, <span class="string"><span class="delimiter">'</span><span class="content">company</span><span class="delimiter">'</span></span>, <span class="string"><span class="delimiter">'</span><span class="content">created</span><span class="delimiter">'</span></span>, <span class="string"><span class="delimiter">'</span><span class="content">application</span><span class="delimiter">'</span></span>). + by().by().by(<span class="string"><span class="delimiter">'</span><span class="content">creationDate</span><span class="delimiter">'</span></span>).by() +==>[<span class="key">job</span>:v[<span class="integer">14</span>],<span class="key">company</span>:v[<span class="integer">6</span>],<span class="key">created</span>:<span class="integer">12</span>/<span class="integer">18</span>/<span class="integer">2015</span>,<span class="key">application</span>:v[<span class="integer">20</span>]] +gremlin> g.V(vRexsterJob1, vBlueprintsJob1).as(<span class="string"><span class="delimiter">'</span><span class="content">job</span><span class="delimiter">'</span></span>). + inE(<span class="string"><span class="delimiter">'</span><span class="content">created</span><span class="delimiter">'</span></span>).as(<span class="string"><span class="delimiter">'</span><span class="content">created</span><span class="delimiter">'</span></span>). + outV().as(<span class="string"><span class="delimiter">'</span><span class="content">company</span><span class="delimiter">'</span></span>). + select(<span class="string"><span class="delimiter">'</span><span class="content">job</span><span class="delimiter">'</span></span>). + coalesce(__.in(<span class="string"><span class="delimiter">'</span><span class="content">appliesTo</span><span class="delimiter">'</span></span>).where(__.in(<span class="string"><span class="delimiter">'</span><span class="content">completes</span><span class="delimiter">'</span></span>).is(vBob)), + constant(<span class="predefined-constant">false</span>)).as(<span class="string"><span class="delimiter">'</span><span class="content">application</span><span class="delimiter">'</span></span>). + select(<span class="string"><span class="delimiter">'</span><span class="content">job</span><span class="delimiter">'</span></span>, <span class="string"><span class="delimiter">'</span><span class="content">company</span><span class="delimiter">'</span></span>, <span class="string"><span class="delimiter">'</span><span class="content">created</span><span class="delimiter">'</span></span>, <span class="string"><span class="delimiter">'</span><span class="content">application</span><span class="delimiter">'</span></span>). + by().by().by(<span class="string"><span class="delimiter">'</span><span class="content">creationDate</span><span class="delimiter">'</span></span>).by() +==>[<span class="key">job</span>:v[<span class="integer">14</span>],<span class="key">company</span>:v[<span class="integer">6</span>],<span class="key">created</span>:<span class="integer">12</span>/<span class="integer">18</span>/<span class="integer">2015</span>,<span class="key">application</span>:<span class="predefined-constant">false</span>] +==>[<span class="key">job</span>:v[<span class="integer">8</span>],<span class="key">company</span>:v[<span class="integer">4</span>],<span class="key">created</span>:<span class="integer">12</span>/<span class="integer">20</span>/<span class="integer">2015</span>,<span class="key">application</span>:v[<span class="integer">16</span>]]</code></pre> +</div> +</div> +<div class="paragraph"> +<p>While the traversals above are more complex, the pattern for finding "things" between two vertices is largely the same. +Note the use of the <code>where()</code> step to terminate the traversers for a specific user. It is embedded in a <code>coalesce()</code> +step to handle situations where the specified user did not complete an application for the specified job and will +return <code>false</code> in those cases.</p> +</div> +</div> +</div> +<div class="sect1"> +<h2 id="centrality">Centrality</h2> +<div class="sectionbody"> +<div class="paragraph"> +<p>There are many measures of <a href="https://en.wikipedia.org/wiki/Centrality";>centrality</a> which are meant to help identify +the most important vertices in a graph. As these measures are common in graph theory, this section attempts to +demonstrate how some of these different indicators can be calculated using Gremlin.</p> +</div> +<div class="sect2"> +<h3 id="degree-centrality">Degree Centrality</h3> +<div class="paragraph"> +<p><a href="https://en.wikipedia.org/wiki/Centrality#Degree_centrality";>Degree centrality</a> is a measure of the number of +edges associated to each vertex. The following examples use the modern toy graph:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="groovy language-groovy">gremlin> g.V().group().by().by(bothE().count()) <span class="comment">//</span><b>(1)</b> +==>[v[<span class="integer">1</span>]:<span class="integer">3</span>,v[<span class="integer">2</span>]:<span class="integer">1</span>,v[<span class="integer">3</span>]:<span class="integer">3</span>,v[<span class="integer">4</span>]:<span class="integer">3</span>,v[<span class="integer">5</span>]:<span class="integer">1</span>,v[<span class="integer">6</span>]:<span class="integer">1</span>] +gremlin> g.V().group().by().by(inE().count()) <span class="comment">//</span><b>(2)</b> +==>[v[<span class="integer">1</span>]:<span class="integer">0</span>,v[<span class="integer">2</span>]:<span class="integer">1</span>,v[<span class="integer">3</span>]:<span class="integer">3</span>,v[<span class="integer">4</span>]:<span class="integer">1</span>,v[<span class="integer">5</span>]:<span class="integer">1</span>,v[<span class="integer">6</span>]:<span class="integer">0</span>] +gremlin> g.V().group().by().by(outE().count()) <span class="comment">//</span><b>(3)</b> +==>[v[<span class="integer">1</span>]:<span class="integer">3</span>,v[<span class="integer">2</span>]:<span class="integer">0</span>,v[<span class="integer">3</span>]:<span class="integer">0</span>,v[<span class="integer">4</span>]:<span class="integer">2</span>,v[<span class="integer">5</span>]:<span class="integer">0</span>,v[<span class="integer">6</span>]:<span class="integer">1</span>] +gremlin> g.V().project(<span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">degree</span><span class="delimiter">"</span></span>).by().by(bothE().count()) <span class="comment">//</span><b>(4)</b> +==>[<span class="key">v</span>:v[<span class="integer">1</span>],<span class="key">degree</span>:<span class="integer">3</span>] +==>[<span class="key">v</span>:v[<span class="integer">2</span>],<span class="key">degree</span>:<span class="integer">1</span>] +==>[<span class="key">v</span>:v[<span class="integer">3</span>],<span class="key">degree</span>:<span class="integer">3</span>] +==>[<span class="key">v</span>:v[<span class="integer">4</span>],<span class="key">degree</span>:<span class="integer">3</span>] +==>[<span class="key">v</span>:v[<span class="integer">5</span>],<span class="key">degree</span>:<span class="integer">1</span>] +==>[<span class="key">v</span>:v[<span class="integer">6</span>],<span class="key">degree</span>:<span class="integer">1</span>] +gremlin> g.V().project(<span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">degree</span><span class="delimiter">"</span></span>).by().by(bothE().count()). <span class="comment">//</span><b>(5)</b> + order().by(select(<span class="string"><span class="delimiter">"</span><span class="content">degree</span><span class="delimiter">"</span></span>), decr). + limit(<span class="integer">4</span>) +==>[<span class="key">v</span>:v[<span class="integer">1</span>],<span class="key">degree</span>:<span class="integer">3</span>] +==>[<span class="key">v</span>:v[<span class="integer">3</span>],<span class="key">degree</span>:<span class="integer">3</span>] +==>[<span class="key">v</span>:v[<span class="integer">4</span>],<span class="key">degree</span>:<span class="integer">3</span>] +==>[<span class="key">v</span>:v[<span class="integer">2</span>],<span class="key">degree</span>:<span class="integer">1</span>]</code></pre> +</div> +</div> +<div class="colist arabic"> +<ol> +<li> +<p>Calculation of degree centrality which counts all incident edges on each vertex to include those that are both +incoming and outgoing.</p> +</li> +<li> +<p>Calculation of in-degree centrality which only counts incoming edges to a vertex.</p> +</li> +<li> +<p>Calculation of out-degree centrality which only counts outgoing edges from a vertex.</p> +</li> +<li> +<p>The previous examples all produce a single <code>Map</code> as their output. While that is a desireable output, producing a +stream of <code>Map</code> objects can allow some greater flexibility.</p> +</li> +<li> +<p>For example, use of a stream enables use of an ordered limit that can be executed in a distributed fashion in +OLAP traversals.</p> +</li> +</ol> +</div> +<div class="admonitionblock note"> +<table> +<tr> +<td class="icon"> +<div class="title">Note</div> +</td> +<td class="content"> +The <a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/reference/#group-step";>group</a> step takes up to two separate +<a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/reference/#by-step";>by</a> modulators. The first <code>by()</code> tells <code>group()</code> +what the key in the resulting <code>Map</code> will be (i.e. the value to group on). In the above examples, the <code>by()</code> is empty +and as a result, the grouping will be on the incoming <code>Vertex</code> object itself. The second <code>by()</code> is the value to be +stored in the <code>Map</code> for each key. +</td> +</tr> +</table> +</div> +</div> +<div class="sect2"> +<h3 id="betweeness-centrality">Betweeness Centrality</h3> +<div class="paragraph"> +<p><a href="https://en.wikipedia.org/wiki/Betweenness_centrality";>Betweeness centrality</a> is a measure of the number of times +a vertex is found between the <a href="#shortest-path">shortest path</a> of each vertex pair in a graph. Consider the following +graph for demonstration purposes:</p> +</div> +<div class="paragraph"> +<p><span class="image"><img src="../images/betweeness-example.png" alt="betweeness-example" width="600"></span></p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="groovy language-groovy">gremlin> g.addV().property(id,<span class="string"><span class="delimiter">'</span><span class="content">A</span><span class="delimiter">'</span></span>).as(<span class="string"><span class="delimiter">'</span><span class="content">a</span><span class="delimiter">'</span></span>). + addV().property(id,<span class="string"><span class="delimiter">'</span><span class="content">B</span><span class="delimiter">'</span></span>).as(<span class="string"><span class="delimiter">'</span><span class="content">b</span><span class="delimiter">'</span></span>). + addV().property(id,<span class="string"><span class="delimiter">'</span><span class="content">C</span><span class="delimiter">'</span></span>).as(<span class="string"><span class="delimiter">'</span><span class="content">c</span><span class="delimiter">'</span></span>). + addV().property(id,<span class="string"><span class="delimiter">'</span><span class="content">D</span><span class="delimiter">'</span></span>).as(<span class="string"><span class="delimiter">'</span><span class="content">d</span><span class="delimiter">'</span></span>). + addV().property(id,<span class="string"><span class="delimiter">'</span><span class="content">E</span><span class="delimiter">'</span></span>).as(<span class="string"><span class="delimiter">'</span><span class="content">e</span><span class="delimiter">'</span></span>). + addV().property(id,<span class="string"><span class="delimiter">'</span><span class="content">F</span><span class="delimiter">'</span></span>).as(<span class="string"><span class="delimiter">'</span><span class="content">f</span><span class="delimiter">'</span></span>). + addE(<span class="string"><span class="delimiter">'</span><span class="content">next</span><span class="delimiter">'</span></span>).from(<span class="string"><span class="delimiter">'</span><span class="content">a</span><span class="delimiter">'</span></span>).to(<span class="string"><span class="delimiter">'</span><span class="content">b</span><span class="delimiter">'</span></span>). + addE(<span class="string"><span class="delimiter">'</span><span class="content">next</span><span class="delimiter">'</span></span>).from(<span class="string"><span class="delimiter">'</span><span class="content">b</span><span class="delimiter">'</span></span>).to(<span class="string"><span class="delimiter">'</span><span class="content">c</span><span class="delimiter">'</span></span>). + addE(<span class="string"><span class="delimiter">'</span><span class="content">next</span><span class="delimiter">'</span></span>).from(<span class="string"><span class="delimiter">'</span><span class="content">b</span><span class="delimiter">'</span></span>).to(<span class="string"><span class="delimiter">'</span><span class="content">d</span><span class="delimiter">'</span></span>). + addE(<span class="string"><span class="delimiter">'</span><span class="content">next</span><span class="delimiter">'</span></span>).from(<span class="string"><span class="delimiter">'</span><span class="content">c</span><span class="delimiter">'</span></span>).to(<span class="string"><span class="delimiter">'</span><span class="content">e</span><span class="delimiter">'</span></span>). + addE(<span class="string"><span class="delimiter">'</span><span class="content">next</span><span class="delimiter">'</span></span>).from(<span class="string"><span class="delimiter">'</span><span class="content">d</span><span class="delimiter">'</span></span>).to(<span class="string"><span class="delimiter">'</span><span class="content">e</span><span class="delimiter">'</span></span>). + addE(<span class="string"><span class="delimiter">'</span><span class="content">next</span><span class="delimiter">'</span></span>).from(<span class="string"><span class="delimiter">'</span><span class="content">e</span><span class="delimiter">'</span></span>).to(<span class="string"><span class="delimiter">'</span><span class="content">f</span><span class="delimiter">'</span></span>).iterate() +gremlin> g.V().as(<span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>). <span class="comment">//</span><b>(1)</b> + repeat(both().simplePath().as(<span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>)).emit(). <span class="comment">//</span><b>(2)</b> + filter(project(<span class="string"><span class="delimiter">"</span><span class="content">x</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">y</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">z</span><span class="delimiter">"</span></span>).by(select(first, <span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>)). <span class="comment">//</span><b>(3)</b> + by(select(last, <span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>)). + by(select(all, <span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>).count(local)).as(<span class="string"><span class="delimiter">"</span><span class="content">triple</span><span class="delimiter">"</span></span>). + coalesce(select(<span class="string"><span class="delimiter">"</span><span class="content">x</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">y</span><span class="delimiter">"</span></span>).as(<span class="string"><span class="delimiter">"</span><span class="content">a</span><span class="delimiter">"</span></span>). <span class="comment">//</span><b>(4)</b> + select(<span class="string"><span class="delimiter">"</span><span class="content">triples</span><span class="delimiter">"</span></span>).unfold().as(<span class="string"><span class="delimiter">"</span><span class="content">t</span><span class="delimiter">"</span></span>). + select(<span class="string"><span class="delimiter">"</span><span class="content">x</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">y</span><span class="delimiter">"</span></span>).where(eq(<span class="string"><span class="delimiter">"</span><span class="content">a</span><span class="delimiter">"</span></span>)). + select(<span class="string"><span class="delimiter">"</span><span class="content">t</span><span class="delimiter">"</span></span>), + store(<span class="string"><span class="delimiter">"</span><span class="content">triples</span><span class="delimiter">"</span></span>)). <span class="comment">//</span><b>(5)</b> + select(<span class="string"><span class="delimiter">"</span><span class="content">z</span><span class="delimiter">"</span></span>).as(<span class="string"><span class="delimiter">"</span><span class="content">length</span><span class="delimiter">"</span></span>). + select(<span class="string"><span class="delimiter">"</span><span class="content">triple</span><span class="delimiter">"</span></span>).select(<span class="string"><span class="delimiter">"</span><span class="content">z</span><span class="delimiter">"</span></span>).where(eq(<span class="string"><span class="delimiter">"</span><span class="content">length</span><span class="delimiter">"</span></span>))). <span class="comment">//</span><b>(6)</b> + select(all, <span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>).unfold(). <span class="comment">//</span><b>(7)</b> + groupCount().next() <span class="comment">//</span><b>(8)</b> +==>v[A]=<span class="integer">14</span> +==>v[B]=<span class="integer">28</span> +==>v[C]=<span class="integer">20</span> +==>v[D]=<span class="integer">20</span> +==>v[E]=<span class="integer">28</span> +==>v[F]=<span class="integer">14</span></code></pre> +</div> +</div> +<div class="colist arabic"> +<ol> +<li> +<p>Starting from each vertex in the graph…</p> +</li> +<li> +<p>…traverse on both - incoming and outgoing - edges, avoiding <a href="#cycle-detection">cyclic paths</a>.</p> +</li> +<li> +<p>Create a triple consisting of the first vertex, the last vertex and the length of the path between them.</p> +</li> +<li> +<p>Determine whether a path between those two vertices was already found.</p> +</li> +<li> +<p>If this is the first path between the two vertices, store the triple in an internal collection named "triples".</p> +</li> +<li> +<p>Keep only those paths between a pair of vertices that have the same length as the first path that was found between them.</p> +</li> +<li> +<p>Select all shortest paths and unfold them.</p> +</li> +<li> +<p>Count the number of occurrences of each vertex, which is ultimately its betweeness score.</p> +</li> +</ol> +</div> +<div class="admonitionblock warning"> +<table> +<tr> +<td class="icon"> +<div class="title">Warning</div> +</td> +<td class="content"> +Since the betweeness centrality algorithm requires the shortest path between any pair of vertices in the graph, +its practical applications are very limited. It’s recommended to use this algorithm only on small subgraphs (graphs like +the <a href="http://tinkerpop.apache.org/docs/current/reference/#grateful-dead";>Grateful Dead graph</a> with only 808 vertices +and 8049 edges already require a massive amount of compute resources to determine the shortest paths between all vertex +pairs). +</td> +</tr> +</table> +</div> +</div> +<div class="sect2"> +<h3 id="closeness-centrality">Closeness Centrality</h3> +<div class="paragraph"> +<p><a href="https://en.wikipedia.org/wiki/Centrality";>Closeness centrality</a> is a measure of the distance of one vertex to all +other reachable vertices in the graph. The following examples use the modern toy graph:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="groovy language-groovy">gremlin> g = TinkerFactory.createModern().traversal() +==>graphtraversalsource[tinkergraph[<span class="key">vertices</span>:<span class="integer">6</span> <span class="key">edges</span>:<span class="integer">6</span>], standard] +gremlin> g.withSack(<span class="float">1f</span>).V().as(<span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>). <span class="comment">//</span><b>(1)</b> + repeat(both().simplePath().as(<span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>)).emit(). <span class="comment">//</span><b>(2)</b> + filter(project(<span class="string"><span class="delimiter">"</span><span class="content">x</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">y</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">z</span><span class="delimiter">"</span></span>).by(select(first, <span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>)). <span class="comment">//</span><b>(3)</b> + by(select(last, <span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>)). + by(select(all, <span class="string"><span class="delimiter">"</span><span class="content">v</span><span class="delimiter">"</span></span>).count(local)).as(<span class="string"><span class="delimiter">"</span><span class="content">triple</span><span class="delimiter">"</span></span>). + coalesce(select(<span class="string"><span class="delimiter">"</span><span class="content">x</span><span class="delimiter">"</span></span>,<span class="string"><span class="delimiter">"</span><span class="content">y</span><span class="delimiter">"</span></span>).as(<span class="string"><span class="delimiter">"</span><span class="content">a</span><span class="delimiter">"</span></span>). <span class="comment">//</span><b>(4)</b>
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