Added: tinkerpop/site/docs/3.2.6-SNAPSHOT/dev/provider/index.html URL: http://svn.apache.org/viewvc/tinkerpop/site/docs/3.2.6-SNAPSHOT/dev/provider/index.html?rev=1799018&view=auto ============================================================================== --- tinkerpop/site/docs/3.2.6-SNAPSHOT/dev/provider/index.html (added) +++ tinkerpop/site/docs/3.2.6-SNAPSHOT/dev/provider/index.html Sat Jun 17 18:56:29 2017 @@ -0,0 +1,3061 @@ +<!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>Provider Documentation</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. Correct `color` not being inherited in IE 8/9. 2. Remove padding so people aren't caught out if they zero out fieldsets. */ +legend { border: 0; /* 1 */ padding: 0; /* 2 */ } + +/** 1. Correct font family not being inherited in all browsers. 2. Correct font size not being inherited in all browsers. 3. Address margins set differently in Firefox 4+, Safari 5, and Chrome. */ +button, input, select, textarea { font-family: inherit; /* 1 */ font-size: 100%; /* 2 */ margin: 0; /* 3 */ } + +/** Address Firefox 4+ setting `line-height` on `input` using `!important` in the UA stylesheet. */ +button, input { line-height: normal; } + +/** Address inconsistent `text-transform` inheritance for `button` and `select`. All other form control elements do not inherit `text-transform` values. Correct `button` style inheritance in Chrome, Safari 5+, and IE 8+. Correct `select` style inheritance in Firefox 4+ and Opera. */ +button, select { text-transform: none; } + +/** 1. 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; 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TinkerPop refers to those third-parties as "providers" and this +documentation is designed to help providers understand what is involved in developing code on these lower levels of +the TinkerPop API.</p> +</div> +<div class="paragraph"> +<p>This document attempts to address the needs of the different providers that have been identified:</p> +</div> +<div class="ulist"> +<ul> +<li> +<p>Graph System Provider</p> +<div class="ulist"> +<ul> +<li> +<p>Graph Database Provider</p> +</li> +<li> +<p>Graph Processor Provider</p> +</li> +</ul> +</div> +</li> +<li> +<p>Graph Driver Provider</p> +</li> +<li> +<p>Graph Language Provider</p> +</li> +<li> +<p>Graph Plugin Provider</p> +</li> +</ul> +</div> +<div class="sect1"> +<h2 id="graph-system-provider-requirements">Graph System Provider Requirements</h2> +<div class="sectionbody"> +<div class="paragraph"> +<p><span class="image" style="float: left"><img src="../../images/tinkerpop-enabled.png" alt="tinkerpop-enabled" width="140"></span> At the core of TinkerPop3 is a Java8 API. The implementation of this +core API and its validation via the <code>gremlin-test</code> suite is all that is required of a graph system provider wishing to +provide a TinkerPop3-enabled graph engine. Once a graph system has a valid implementation, then all the applications +provided by TinkerPop (e.g. Gremlin Console, Gremlin Server, etc.) and 3rd-party developers (e.g. Gremlin-Scala, +Gremlin-JS, etc.) will integrate properly. Finally, please feel free to use the logo on the left to promote your +TinkerPop3 implementation.</p> +</div> +<div class="sect2"> +<h3 id="_implementing_gremlin_core">Implementing Gremlin-Core</h3> +<div class="paragraph"> +<p>The classes that a graph system provider should focus on implementing are itemized below. It is a good idea to study +the <a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/reference/#tinkergraph-gremlin";>TinkerGraph</a> (in-memory OLTP and OLAP +in <code>tinkergraph-gremlin</code>), <a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/reference/#neo4j-gremlin";>Neo4jGraph</a> +(OLTP w/ transactions in <code>neo4j-gremlin</code>) and/or +<a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/reference/#hadoop-gremlin";>HadoopGraph</a> (OLAP in <code>hadoop-gremlin</code>) +implementations for ideas and patterns.</p> +</div> +<div class="olist arabic"> +<ol class="arabic"> +<li> +<p>Online Transactional Processing Graph Systems (<strong>OLTP</strong>)</p> +<div class="olist loweralpha"> +<ol class="loweralpha" type="a"> +<li> +<p>Structure API: <code>Graph</code>, <code>Element</code>, <code>Vertex</code>, <code>Edge</code>, <code>Property</code> and <code>Transaction</code> (if transactions are supported).</p> +</li> +<li> +<p>Process API: <code>TraversalStrategy</code> instances for optimizing Gremlin traversals to the provider’s graph system (i.e. <code>TinkerGraphStepStrategy</code>).</p> +</li> +</ol> +</div> +</li> +<li> +<p>Online Analytics Processing Graph Systems (<strong>OLAP</strong>)</p> +<div class="olist loweralpha"> +<ol class="loweralpha" type="a"> +<li> +<p>Everything required of OLTP is required of OLAP (but not vice versa).</p> +</li> +<li> +<p>GraphComputer API: <code>GraphComputer</code>, <code>Messenger</code>, <code>Memory</code>.</p> +</li> +</ol> +</div> +</li> +</ol> +</div> +<div class="paragraph"> +<p>Please consider the following implementation notes:</p> +</div> +<div class="ulist"> +<ul> +<li> +<p>Be sure your <code>Graph</code> implementation is named as <code>XXXGraph</code> (e.g. TinkerGraph, Neo4jGraph, HadoopGraph, etc.).</p> +</li> +<li> +<p>Use <code>StringHelper</code> to ensuring that the <code>toString()</code> representation of classes are consistent with other implementations.</p> +</li> +<li> +<p>Ensure that your implementation’s <code>Features</code> (Graph, Vertex, etc.) are correct so that test cases handle particulars accordingly.</p> +</li> +<li> +<p>Use the numerous static method helper classes such as <code>ElementHelper</code>, <code>GraphComputerHelper</code>, <code>VertexProgramHelper</code>, etc.</p> +</li> +<li> +<p>There are a number of default methods on the provided interfaces that are semantically correct. However, if they are +not efficient for the implementation, override them.</p> +</li> +<li> +<p>Implement the <code>structure/</code> package interfaces first and then, if desired, interfaces in the <code>process/</code> package interfaces.</p> +</li> +<li> +<p><code>ComputerGraph</code> is a <code>Wrapper</code> system that ensure proper semantics during a GraphComputer computation.</p> +</li> +</ul> +</div> +<div class="sect3"> +<h4 id="oltp-implementations">OLTP Implementations</h4> +<div class="paragraph"> +<p><span class="image" style="float: right"><img src="../../images/pipes-character-1.png" alt="pipes-character-1" width="110"></span> The most important interfaces to implement are in the <code>structure/</code> +package. These include interfaces like Graph, Vertex, Edge, Property, Transaction, etc. The <code>StructureStandardSuite</code> +will ensure that the semantics of the methods implemented are correct. Moreover, there are numerous <code>Exceptions</code> +classes with static exceptions that should be thrown by the graph system so that all the exceptions and their +messages are consistent amongst all TinkerPop3 implementations.</p> +</div> +</div> +<div class="sect3"> +<h4 id="olap-implementations">OLAP Implementations</h4> +<div class="paragraph"> +<p><span class="image" style="float: right"><img src="../../images/furnace-character-1.png" alt="furnace-character-1" width="110"></span> Implementing the OLAP interfaces may be a bit more complicated. +Note that before OLAP interfaces are implemented, it is necessary for the OLTP interfaces to be, at minimal, +implemented as specified in <a href="#oltp-implementations">OLTP Implementations</a>. A summary of each required interface +implementation is presented below:</p> +</div> +<div class="olist arabic"> +<ol class="arabic"> +<li> +<p><code>GraphComputer</code>: A fluent builder for specifying an isolation level, a VertexProgram, and any number of MapReduce jobs to be submitted.</p> +</li> +<li> +<p><code>Memory</code>: A global blackboard for ANDing, ORing, INCRing, and SETing values for specified keys.</p> +</li> +<li> +<p><code>Messenger</code>: The system that collects and distributes messages being propagated by vertices executing the VertexProgram application.</p> +</li> +<li> +<p><code>MapReduce.MapEmitter</code>: The system that collects key/value pairs being emitted by the MapReduce applications map-phase.</p> +</li> +<li> +<p><code>MapReduce.ReduceEmitter</code>: The system that collects key/value pairs being emitted by the MapReduce applications combine- and reduce-phases.</p> +</li> +</ol> +</div> +<div class="admonitionblock note"> +<table> +<tr> +<td class="icon"> +<div class="title">Note</div> +</td> +<td class="content"> +The VertexProgram and MapReduce interfaces in the <code>process/computer/</code> package are not required by the graph +system. Instead, these are interfaces to be implemented by application developers writing VertexPrograms and MapReduce jobs. +</td> +</tr> +</table> +</div> +<div class="admonitionblock important"> +<table> +<tr> +<td class="icon"> +<div class="title">Important</div> +</td> +<td class="content"> +TinkerPop3 provides three OLAP implementations: +<a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/reference/#tinkergraph-gremlin";>TinkerGraphComputer</a> (TinkerGraph), +<a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/reference/#giraphgraphcomputer";>GiraphGraphComputer</a> (HadoopGraph), and +<a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/reference/#sparkgraphcomputer";>SparkGraphComputer</a> (Hadoop). +Given the complexity of the OLAP system, it is good to study and copy many of the patterns used in these reference +implementations. +</td> +</tr> +</table> +</div> +<div class="sect4"> +<h5 id="_implementing_graphcomputer">Implementing GraphComputer</h5> +<div class="paragraph"> +<p><span class="image" style="float: right"><img src="../../images/furnace-character-3.png" alt="furnace-character-3" width="150"></span> The most complex method in GraphComputer is the <code>submit()</code>-method. The method must do the following:</p> +</div> +<div class="olist arabic"> +<ol class="arabic"> +<li> +<p>Ensure the GraphComputer has not already been executed.</p> +</li> +<li> +<p>Ensure that at least there is a VertexProgram or 1 MapReduce job.</p> +</li> +<li> +<p>If there is a VertexProgram, validate that it can execute on the GraphComputer given the respectively defined features.</p> +</li> +<li> +<p>Create the Memory to be used for the computation.</p> +</li> +<li> +<p>Execute the VertexProgram.setup() method once and only once.</p> +</li> +<li> +<p>Execute the VertexProgram.execute() method for each vertex.</p> +</li> +<li> +<p>Execute the VertexProgram.terminate() method once and if true, repeat VertexProgram.execute().</p> +</li> +<li> +<p>When VertexProgram.terminate() returns true, move to MapReduce job execution.</p> +</li> +<li> +<p>MapReduce jobs are not required to be executed in any specified order.</p> +</li> +<li> +<p>For each Vertex, execute MapReduce.map(). Then (if defined) execute MapReduce.combine() and MapReduce.reduce().</p> +</li> +<li> +<p>Update Memory with runtime information.</p> +</li> +<li> +<p>Construct a new <code>ComputerResult</code> containing the compute Graph and Memory.</p> +</li> +</ol> +</div> +</div> +<div class="sect4"> +<h5 id="_implementing_memory">Implementing Memory</h5> +<div class="paragraph"> +<p><span class="image" style="float: left"><img src="../../images/gremlin-brain.png" alt="gremlin-brain" width="175"></span> The Memory object is initially defined by <code>VertexProgram.setup()</code>. +The memory data is available in the first round of the <code>VertexProgram.execute()</code> method. Each Vertex, when executing +the VertexProgram, can update the Memory in its round. However, the update is not seen by the other vertices until +the next round. At the end of the first round, all the updates are aggregated and the new memory data is available +on the second round. This process repeats until the VertexProgram terminates.</p> +</div> +</div> +<div class="sect4"> +<h5 id="_implementing_messenger">Implementing Messenger</h5> +<div class="paragraph"> +<p>The Messenger object is similar to the Memory object in that a vertex can read and write to the Messenger. However, +the data it reads are the messages sent to the vertex in the previous step and the data it writes are the messages +that will be readable by the receiving vertices in the subsequent round.</p> +</div> +</div> +<div class="sect4"> +<h5 id="_implementing_mapreduce_emitters">Implementing MapReduce Emitters</h5> +<div class="paragraph"> +<p><span class="image" style="float: left"><img src="../../images/hadoop-logo-notext.png" alt="hadoop-logo-notext" width="150"></span> The MapReduce framework in TinkerPop3 is similar to the model +popularized by <a href="http://hadoop.apache.org";>Hadoop</a>. The primary difference is that all Mappers process the vertices +of the graph, not an arbitrary key/value pair. However, the vertices' edges can not be accessed — only their +properties. This greatly reduces the amount of data needed to be pushed through the MapReduce engine as any edge +information required, can be computed in the VertexProgram.execute() method. Moreover, at this stage, vertices can +not be mutated, only their token and property data read. A Gremlin OLAP system needs to provide implementations for +to particular classes: <code>MapReduce.MapEmitter</code> and <code>MapReduce.ReduceEmitter</code>. TinkerGraph’s implementation is provided +below which demonstrates the simplicity of the algorithm (especially when the data is all within the same JVM).</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="directive">public</span> <span class="type">class</span> <span class="class">TinkerMapEmitter</span><K, V> <span class="directive">implements</span> MapReduce.MapEmitter<K, V> { + + <span class="directive">public</span> <span class="predefined-type">Map</span><K, <span class="predefined-type">Queue</span><V>> reduceMap; + <span class="directive">public</span> <span class="predefined-type">Queue</span><KeyValue<K, V>> mapQueue; + <span class="directive">private</span> <span class="directive">final</span> <span class="type">boolean</span> doReduce; + + <span class="directive">public</span> TinkerMapEmitter(<span class="directive">final</span> <span class="type">boolean</span> doReduce) { <b>(1)</b> + <span class="local-variable">this</span>.doReduce = doReduce; + <span class="keyword">if</span> (<span class="local-variable">this</span>.doReduce) + <span class="local-variable">this</span>.reduceMap = <span class="keyword">new</span> <span class="predefined-type">ConcurrentHashMap</span><>(); + <span class="keyword">else</span> + <span class="local-variable">this</span>.mapQueue = <span class="keyword">new</span> <span class="predefined-type">ConcurrentLinkedQueue</span><>(); + } + + <span class="annotation">@Override</span> + <span class="directive">public</span> <span class="type">void</span> emit(K key, V value) { + <span class="keyword">if</span> (<span class="local-variable">this</span>.doReduce) + <span class="local-variable">this</span>.reduceMap.computeIfAbsent(key, k -> <span class="keyword">new</span> <span class="predefined-type">ConcurrentLinkedQueue</span><>()).add(value); <b>(2)</b> + <span class="keyword">else</span> + <span class="local-variable">this</span>.mapQueue.add(<span class="keyword">new</span> KeyValue<>(key, value)); <b>(3)</b> + } + + <span class="directive">protected</span> <span class="type">void</span> complete(<span class="directive">final</span> MapReduce<K, V, ?, ?, ?> mapReduce) { + <span class="keyword">if</span> (!<span class="local-variable">this</span>.doReduce && mapReduce.getMapKeySort().isPresent()) { <b>(4)</b> + <span class="directive">final</span> <span class="predefined-type">Comparator</span><K> comparator = mapReduce.getMapKeySort().get(); + <span class="directive">final</span> <span class="predefined-type">List</span><KeyValue<K, V>> list = <span class="keyword">new</span> <span class="predefined-type">ArrayList</span><>(<span class="local-variable">this</span>.mapQueue); + <span class="predefined-type">Collections</span>.sort(list, <span class="predefined-type">Comparator</span>.comparing(KeyValue::getKey, comparator)); + <span class="local-variable">this</span>.mapQueue.clear(); + <span class="local-variable">this</span>.mapQueue.addAll(list); + } <span class="keyword">else</span> <span class="keyword">if</span> (mapReduce.getMapKeySort().isPresent()) { + <span class="directive">final</span> <span class="predefined-type">Comparator</span><K> comparator = mapReduce.getMapKeySort().get(); + <span class="directive">final</span> <span class="predefined-type">List</span><<span class="predefined-type">Map</span>.Entry<K, <span class="predefined-type">Queue</span><V>>> list = <span class="keyword">new</span> <span class="predefined-type">ArrayList</span><>(); + list.addAll(<span class="local-variable">this</span>.reduceMap.entrySet()); + <span class="predefined-type">Collections</span>.sort(list, <span class="predefined-type">Comparator</span>.comparing(<span class="predefined-type">Map</span>.Entry::getKey, comparator)); + <span class="local-variable">this</span>.reduceMap = <span class="keyword">new</span> <span class="predefined-type">LinkedHashMap</span><>(); + list.forEach(entry -> <span class="local-variable">this</span>.reduceMap.put(entry.getKey(), entry.getValue())); + } + } +}</code></pre> +</div> +</div> +<div class="colist arabic"> +<ol> +<li> +<p>If the MapReduce job has a reduce, then use one data structure (<code>reduceMap</code>), else use another (<code>mapList</code>). The +difference being that a reduction requires a grouping by key and therefore, the <code>Map<K,Queue<V>></code> definition. If no +reduction/grouping is required, then a simple <code>Queue<KeyValue<K,V>></code> can be leveraged.</p> +</li> +<li> +<p>If reduce is to follow, then increment the Map with a new value for the key. <code>MapHelper</code> is a TinkerPop3 class +with static methods for adding data to a Map.</p> +</li> +<li> +<p>If no reduce is to follow, then simply append a KeyValue to the queue.</p> +</li> +<li> +<p>When the map phase is complete, any map-result sorting required can be executed at this point.</p> +</li> +</ol> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="directive">public</span> <span class="type">class</span> <span class="class">TinkerReduceEmitter</span><OK, OV> <span class="directive">implements</span> MapReduce.ReduceEmitter<OK, OV> { + + <span class="directive">protected</span> <span class="predefined-type">Queue</span><KeyValue<OK, OV>> reduceQueue = <span class="keyword">new</span> <span class="predefined-type">ConcurrentLinkedQueue</span><>(); + + <span class="annotation">@Override</span> + <span class="directive">public</span> <span class="type">void</span> emit(<span class="directive">final</span> OK key, <span class="directive">final</span> OV value) { + <span class="local-variable">this</span>.reduceQueue.add(<span class="keyword">new</span> KeyValue<>(key, value)); + } + + <span class="directive">protected</span> <span class="type">void</span> complete(<span class="directive">final</span> MapReduce<?, ?, OK, OV, ?> mapReduce) { + <span class="keyword">if</span> (mapReduce.getReduceKeySort().isPresent()) { + <span class="directive">final</span> <span class="predefined-type">Comparator</span><OK> comparator = mapReduce.getReduceKeySort().get(); + <span class="directive">final</span> <span class="predefined-type">List</span><KeyValue<OK, OV>> list = <span class="keyword">new</span> <span class="predefined-type">ArrayList</span><>(<span class="local-variable">this</span>.reduceQueue); + <span class="predefined-type">Collections</span>.sort(list, <span class="predefined-type">Comparator</span>.comparing(KeyValue::getKey, comparator)); + <span class="local-variable">this</span>.reduceQueue.clear(); + <span class="local-variable">this</span>.reduceQueue.addAll(list); + } + } +}</code></pre> +</div> +</div> +<div class="paragraph"> +<p>The method <code>MapReduce.reduce()</code> is defined as:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="directive">public</span> <span class="type">void</span> reduce(<span class="directive">final</span> OK key, <span class="directive">final</span> <span class="predefined-type">Iterator</span><OV> values, <span class="directive">final</span> ReduceEmitter<OK, OV> emitter) { ... }</code></pre> +</div> +</div> +<div class="paragraph"> +<p>In other words, for the TinkerGraph implementation, iterate through the entrySet of the <code>reduceMap</code> and call the +<code>reduce()</code> method on each entry. The <code>reduce()</code> method can emit key/value pairs which are simply aggregated into a +<code>Queue<KeyValue<OK,OV>></code> in an analogous fashion to <code>TinkerMapEmitter</code> when no reduce is to follow. These two emitters +are tied together in <code>TinkerGraphComputer.submit()</code>.</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java">... +for (<span class="directive">final</span> MapReduce mapReduce : mapReducers) { + <span class="keyword">if</span> (mapReduce.doStage(MapReduce.Stage.MAP)) { + <span class="directive">final</span> TinkerMapEmitter<?, ?> mapEmitter = <span class="keyword">new</span> TinkerMapEmitter<>(mapReduce.doStage(MapReduce.Stage.REDUCE)); + <span class="directive">final</span> SynchronizedIterator<Vertex> vertices = <span class="keyword">new</span> SynchronizedIterator<>(<span class="local-variable">this</span>.graph.vertices()); + workers.setMapReduce(mapReduce); + workers.mapReduceWorkerStart(MapReduce.Stage.MAP); + workers.executeMapReduce(workerMapReduce -> { + <span class="keyword">while</span> (<span class="predefined-constant">true</span>) { + <span class="directive">final</span> Vertex vertex = vertices.next(); + <span class="keyword">if</span> (<span class="predefined-constant">null</span> == vertex) <span class="keyword">return</span>; + workerMapReduce.map(ComputerGraph.mapReduce(vertex), mapEmitter); + } + }); + workers.mapReduceWorkerEnd(MapReduce.Stage.MAP); + + <span class="comment">// sort results if a map output sort is defined</span> + mapEmitter.complete(mapReduce); + + <span class="comment">// no need to run combiners as this is single machine</span> + <span class="keyword">if</span> (mapReduce.doStage(MapReduce.Stage.REDUCE)) { + <span class="directive">final</span> TinkerReduceEmitter<?, ?> reduceEmitter = <span class="keyword">new</span> TinkerReduceEmitter<>(); + <span class="directive">final</span> SynchronizedIterator<<span class="predefined-type">Map</span>.Entry<?, <span class="predefined-type">Queue</span><?>>> keyValues = <span class="keyword">new</span> SynchronizedIterator((<span class="predefined-type">Iterator</span>) mapEmitter.reduceMap.entrySet().iterator()); + workers.mapReduceWorkerStart(MapReduce.Stage.REDUCE); + workers.executeMapReduce(workerMapReduce -> { + <span class="keyword">while</span> (<span class="predefined-constant">true</span>) { + <span class="directive">final</span> <span class="predefined-type">Map</span>.Entry<?, <span class="predefined-type">Queue</span><?>> entry = keyValues.next(); + <span class="keyword">if</span> (<span class="predefined-constant">null</span> == entry) <span class="keyword">return</span>; + workerMapReduce.reduce(entry.getKey(), entry.getValue().iterator(), reduceEmitter); + } + }); + workers.mapReduceWorkerEnd(MapReduce.Stage.REDUCE); + reduceEmitter.complete(mapReduce); <span class="comment">// sort results if a reduce output sort is defined</span> + mapReduce.addResultToMemory(<span class="local-variable">this</span>.memory, reduceEmitter.reduceQueue.iterator()); <b>(1)</b> + } <span class="keyword">else</span> { + mapReduce.addResultToMemory(<span class="local-variable">this</span>.memory, mapEmitter.mapQueue.iterator()); <b>(2)</b> + } + } +} +...</code></pre> +</div> +</div> +<div class="colist arabic"> +<ol> +<li> +<p>Note that the final results of the reducer are provided to the Memory as specified by the application developer’s +<code>MapReduce.addResultToMemory()</code> implementation.</p> +</li> +<li> +<p>If there is no reduce stage, the map-stage results are inserted into Memory as specified by the application +developer’s <code>MapReduce.addResultToMemory()</code> implementation.</p> +</li> +</ol> +</div> +</div> +</div> +<div class="sect3"> +<h4 id="_hadoop_gremlin_usage">Hadoop-Gremlin Usage</h4> +<div class="paragraph"> +<p>Hadoop-Gremlin is centered around <code>InputFormats</code> and <code>OutputFormats</code>. If a 3rd-party graph system provider wishes to +leverage Hadoop-Gremlin (and its respective <code>GraphComputer</code> engines), then they need to provide, at minimum, a +Hadoop2 <code>InputFormat<NullWritable,VertexWritable></code> for their graph system. If the provider wishes to persist computed +results back to their graph system (and not just to HDFS via a <code>FileOutputFormat</code>), then a graph system specific +<code>OutputFormat<NullWritable,VertexWritable></code> must be developed as well.</p> +</div> +<div class="paragraph"> +<p>Conceptually, <code>HadoopGraph</code> is a wrapper around a <code>Configuration</code> object. There is no "data" in the <code>HadoopGraph</code> as +the <code>InputFormat</code> specifies where and how to get the graph data at OLAP (and OLTP) runtime. Thus, <code>HadoopGraph</code> is a +small object with little overhead. Graph system providers should realize <code>HadoopGraph</code> as the gateway to the OLAP +features offered by Hadoop-Gremlin. For example, a graph system specific <code>Graph.compute(Class<? extends GraphComputer> +graphComputerClass)</code>-method may look as follows:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="directive">public</span> <C <span class="directive">extends</span> GraphComputer> C compute(<span class="directive">final</span> <span class="predefined-type">Class</span><C> graphComputerClass) <span class="directive">throws</span> <span class="exception">IllegalArgumentException</span> { + <span class="keyword">try</span> { + <span class="keyword">if</span> (AbstractHadoopGraphComputer.class.isAssignableFrom(graphComputerClass)) + <span class="keyword">return</span> graphComputerClass.getConstructor(HadoopGraph.class).newInstance(<span class="local-variable">this</span>); + <span class="keyword">else</span> + <span class="keyword">throw</span> Graph.Exceptions.graphDoesNotSupportProvidedGraphComputer(graphComputerClass); + } <span class="keyword">catch</span> (<span class="directive">final</span> <span class="exception">Exception</span> e) { + <span class="keyword">throw</span> <span class="keyword">new</span> <span class="exception">IllegalArgumentException</span>(e.getMessage(),e); + } +}</code></pre> +</div> +</div> +<div class="paragraph"> +<p>Note that the configurations for Hadoop are assumed to be in the <code>Graph.configuration()</code> object. If this is not the +case, then the <code>Configuration</code> provided to <code>HadoopGraph.open()</code> should be dynamically created within the +<code>compute()</code>-method. It is in the provided configuration that <code>HadoopGraph</code> gets the various properties which +determine how to read and write data to and from Hadoop. For instance, <code>gremlin.hadoop.graphReader</code> and +<code>gremlin.hadoop.graphWriter</code>.</p> +</div> +<div class="sect4"> +<h5 id="_graphfilteraware_interface">GraphFilterAware Interface</h5> +<div class="paragraph"> +<p><a href="#graph-filter">Graph filters</a> by OLAP processors to only pull a subgraph of the full graph from the graph data source. For instance, the +example below constructs a <code>GraphFilter</code> that will only pull the "knows"-graph amongst people into the <code>GraphComputer</code> +for processing.</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java">graph.compute().vertices(hasLabel(<span class="string"><span class="delimiter">"</span><span class="content">person</span><span class="delimiter">"</span></span>)).edges(bothE(<span class="string"><span class="delimiter">"</span><span class="content">knows</span><span class="delimiter">"</span></span>))</code></pre> +</div> +</div> +<div class="paragraph"> +<p>If the provider has a custom <code>InputRDD</code>, they can implement <code>GraphFilterAware</code> and that graph filter will be provided to their +<code>InputRDD</code> at load time. For providers that use an <code>InputFormat</code>, state but the graph filter can be accessed from the configuration +as such:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="keyword">if</span> (configuration.containsKey(Constants.GREMLIN_HADOOP_GRAPH_FILTER)) + <span class="local-variable">this</span>.graphFilter = VertexProgramHelper.deserialize(configuration, Constants.GREMLIN_HADOOP_GRAPH_FILTER);</code></pre> +</div> +</div> +</div> +<div class="sect4"> +<h5 id="_persistresultgraphaware_interface">PersistResultGraphAware Interface</h5> +<div class="paragraph"> +<p>A graph system provider’s <code>OutputFormat</code> should implement the <code>PersistResultGraphAware</code> interface which +determines which persistence options are available to the user. For the standard file-based <code>OutputFormats</code> provided +by Hadoop-Gremlin (e.g. <a href="#gryo-io-format"><code>GryoOutputFormat</code></a>, <a href="#graphson-io-format"><code>GraphSONOutputFormat</code></a>, +and <a href="#script-io-format"><code>ScriptInputOutputFormat</code></a>) <code>ResultGraph.ORIGINAL</code> is not supported as the original graph +data files are not random access and are, in essence, immutable. Thus, these file-based <code>OutputFormats</code> only support +<code>ResultGraph.NEW</code> which creates a copy of the data specified by the <code>Persist</code> enum.</p> +</div> +</div> +</div> +<div class="sect3"> +<h4 id="io-implementations">IO Implementations</h4> +<div class="paragraph"> +<p>If a <code>Graph</code> requires custom serializers for IO to work properly, implement the <code>Graph.io</code> method. A typical example +of where a <code>Graph</code> would require such a custom serializers is if their identifier system uses non-primitive values, +such as OrientDB’s <code>Rid</code> class. From basic serialization of a single <code>Vertex</code> all the way up the stack to Gremlin +Server, the need to know how to handle these complex identifiers is an important requirement.</p> +</div> +<div class="paragraph"> +<p>The first step to implementing custom serializers is to first implement the <code>IoRegistry</code> interface and register the +custom classes and serializers to it. Each <code>Io</code> implementation has different requirements for what it expects from the +<code>IoRegistry</code>:</p> +</div> +<div class="ulist"> +<ul> +<li> +<p><strong>GraphML</strong> - No custom serializers expected/allowed.</p> +</li> +<li> +<p><strong>GraphSON</strong> - Register a Jackson <code>SimpleModule</code>. The <code>SimpleModule</code> encapsulates specific classes to be serialized, +so it does not need to be registered to a specific class in the <code>IoRegistry</code> (use <code>null</code>).</p> +</li> +<li> +<p><strong>Gryo</strong> - Expects registration of one of three objects:</p> +<div class="ulist"> +<ul> +<li> +<p>Register just the custom class with a <code>null</code> Kryo <code>Serializer</code> implementation - this class will use default "field-level" Kryo serialization.</p> +</li> +<li> +<p>Register the custom class with a specific Kryo ‘Serializer’ implementation.</p> +</li> +<li> +<p>Register the custom class with a <code>Function<Kryo, Serializer></code> for those cases where the Kryo <code>Serializer</code> requires the <code>Kryo</code> instance to get constructed.</p> +</li> +</ul> +</div> +</li> +</ul> +</div> +<div class="paragraph"> +<p>This implementation should provide a zero-arg constructor as the stack may require instantiation via reflection. +Consider extending <code>AbstractIoRegistry</code> for convenience as follows:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="directive">public</span> <span class="type">class</span> <span class="class">MyGraphIoRegistry</span> <span class="directive">extends</span> AbstractIoRegistry { + <span class="directive">public</span> MyGraphIoRegistry() { + register(GraphSONIo.class, <span class="predefined-constant">null</span>, <span class="keyword">new</span> MyGraphSimpleModule()); + register(GryoIo.class, MyGraphIdClass.class, <span class="keyword">new</span> MyGraphIdSerializer()); + } +}</code></pre> +</div> +</div> +<div class="paragraph"> +<p>In the <code>Graph.io</code> method, provide the <code>IoRegistry</code> object to the supplied <code>Builder</code> and call the <code>create</code> method to +return that <code>Io</code> instance as follows:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="directive">public</span> <I <span class="directive">extends</span> Io> I io(<span class="directive">final</span> Io.Builder<I> builder) { + <span class="keyword">return</span> (I) builder.graph(<span class="local-variable">this</span>).registry(myGraphIoRegistry).create(); +}}</code></pre> +</div> +</div> +<div class="paragraph"> +<p>In this way, <code>Graph</code> implementations can pre-configure custom serializers for IO interactions and users will not need +to know about those details. Following this pattern will ensure proper execution of the test suite as well as +simplified usage for end-users.</p> +</div> +<div class="admonitionblock important"> +<table> +<tr> +<td class="icon"> +<div class="title">Important</div> +</td> +<td class="content"> +Proper implementation of IO is critical to successful <code>Graph</code> operations in Gremlin Server. The Test Suite +does have "serialization" tests that provide some assurance that an implementation is working properly, but those +tests cannot make assertions against any specifics of a custom serializer. It is the responsibility of the +implementer to test the specifics of their custom serializers. +</td> +</tr> +</table> +</div> +<div class="admonitionblock tip"> +<table> +<tr> +<td class="icon"> +<div class="title">Tip</div> +</td> +<td class="content"> +Consider separating serializer code into its own module, if possible, so that clients that use the <code>Graph</code> +implementation remotely don’t need a full dependency on the entire <code>Graph</code> - just the IO components and related +classes being serialized. +</td> +</tr> +</table> +</div> +</div> +<div class="sect3"> +<h4 id="remoteconnection-implementations">RemoteConnection Implementations</h4> +<div class="paragraph"> +<p>A <code>RemoteConnection</code> is an interface that is important for usage on traversal sources configured using the +<a href="http://tinkerpop.apache.org/docs/3.2.6-SNAPSHOT/reference/#connecting-via-remotegraph";>withRemote()</a> option. A <code>Traversal</code> +that is generated from that source will apply a <code>RemoteStrategy</code> which will inject a <code>RemoteStep</code> to its end. That +step will then send the <code>Bytecode</code> of the <code>Traversal</code> over the <code>RemoteConnection</code> to get the results that it will +iterate.</p> +</div> +<div class="paragraph"> +<p>There is one method to implement on <code>RemoteConnection</code>:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="directive">public</span> <E> CompletableFuture<RemoteTraversal<?, E>> submitAsync(<span class="directive">final</span> Bytecode bytecode) <span class="directive">throws</span> RemoteConnectionException;</code></pre> +</div> +</div> +<div class="paragraph"> +<p>Note that it returns a <code>RemoteTraversal</code>. This interface should also be implemented and in most cases implementers can +simply extend the <code>AbstractRemoteTraversal</code>, which provides default implementations for all the <code>Traversal</code> methods +except for the important one <code>getSideEffects()</code>.</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="directive">public</span> RemoteTraversalSideEffects getSideEffects();</code></pre> +</div> +</div> +<div class="paragraph"> +<p>This method has been overriden from <code>Traversal</code> to return <code>RemoteTraversalSideEffects</code> and this interface allows a user +to do a retrieval of any side-effects produced by the <code>Traversal</code>. The assumption, of course, is that the +<code>RemoteConnection</code> is communicating with a server that supports side-effect retreival (as Gremlin Server does).</p> +</div> +<div class="paragraph"> +<p>TinkerPop provides the <code>DriverRemoteConnection</code> as a useful and +<a href="https://github.com/apache/tinkerpop/blob/3.2.6-SNAPSHOT/gremlin-driver/src/main/java/org/apache/tinkerpop/gremlin/driver/remote";>example implementation</a>. +<code>DriverRemoteConnection</code> serializes the <code>Traversal</code> and then submits it for remote processing on Gremlin Server. +Gremlin Server rebinds the <code>Traversal</code> to a configured <code>Graph</code> instance and then iterates the results back as it would +normally do.</p> +</div> +<div class="paragraph"> +<p>Implementing <code>RemoteConnection</code> is not something routinely done for those implementing <code>gremlin-core</code>. It is only +something required if there is a need to exploit <code>withRemote()</code> in some way. If a graph provider has a "graph server" +similar to Gremlin Server that can accept a serialized <code>Traversal</code> instance, then that would be one example of a +reason to implement this interface.</p> +</div> +</div> +</div> +<div class="sect2"> +<h3 id="validating-with-gremlin-test">Validating with Gremlin-Test</h3> +<div class="paragraph"> +<p><span class="image"><img src="../../images/gremlin-edumacated.png" alt="gremlin-edumacated" width="225"></span></p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="xml language-xml"><span class="tag"><dependency></span> + <span class="tag"><groupId></span>org.apache.tinkerpop<span class="tag"></groupId></span> + <span class="tag"><artifactId></span>gremlin-test<span class="tag"></artifactId></span> + <span class="tag"><version></span>3.2.6-SNAPSHOT<span class="tag"></version></span> +<span class="tag"></dependency></span></code></pre> +</div> +</div> +<div class="paragraph"> +<p>The operational semantics of any OLTP or OLAP implementation are validated by <code>gremlin-test</code>. To implement these tests, +provide test case implementations as shown below, where <code>XXX</code> below denotes the name of the graph implementation (e.g. +TinkerGraph, Neo4jGraph, HadoopGraph, etc.).</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="comment">// Structure API tests</span> +<span class="annotation">@RunWith</span>(StructureStandardSuite.class) +<span class="annotation">@GraphProviderClass</span>(provider = XXXGraphProvider.class, graph = XXXGraph.class) +<span class="directive">public</span> <span class="type">class</span> <span class="class">XXXStructureStandardTest</span> {} + +<span class="comment">// Process API tests</span> +<span class="annotation">@RunWith</span>(ProcessComputerSuite.class) +<span class="annotation">@GraphProviderClass</span>(provider = XXXGraphProvider.class, graph = XXXGraph.class) +<span class="directive">public</span> <span class="type">class</span> <span class="class">XXXProcessComputerTest</span> {} + +<span class="annotation">@RunWith</span>(ProcessStandardSuite.class) +<span class="annotation">@GraphProviderClass</span>(provider = XXXGraphProvider.class, graph = XXXGraph.class) +<span class="directive">public</span> <span class="type">class</span> <span class="class">XXXProcessStandardTest</span> {}</code></pre> +</div> +</div> +<div class="paragraph"> +<p>The above set of tests represent the minimum test suite set to implement. There are other "integration" and +"performance" tests that should be considered optional. Implementing those tests requires the same pattern as shown +above.</p> +</div> +<div class="admonitionblock important"> +<table> +<tr> +<td class="icon"> +<div class="title">Important</div> +</td> +<td class="content"> +It is as important to look at "ignored" tests as it is to look at ones that fail. The <code>gremlin-test</code> +suite utilizes the <code>Feature</code> implementation exposed by the <code>Graph</code> to determine which tests to execute. If a test +utilizes features that are not supported by the graph, it will ignore them. While that may be fine, implementers +should validate that the ignored tests are appropriately bypassed and that there are no mistakes in their feature +definitions. Moreover, implementers should consider filling gaps in their own test suites, especially when +IO-related tests are being ignored. +</td> +</tr> +</table> +</div> +<div class="paragraph"> +<p>The only test-class that requires any code investment is the <code>GraphProvider</code> implementation class. This class is a +used by the test suite to construct <code>Graph</code> configurations and instances and provides information about the +implementation itself. In most cases, it is best to simply extend <code>AbstractGraphProvider</code> as it provides many +default implementations of the <code>GraphProvider</code> interface.</p> +</div> +<div class="paragraph"> +<p>Finally, specify the test suites that will be supported by the <code>Graph</code> implementation using the <code>@Graph.OptIn</code> +annotation. See the <code>TinkerGraph</code> implementation below as an example:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="annotation">@Graph</span>.OptIn(Graph.OptIn.SUITE_STRUCTURE_STANDARD) +<span class="annotation">@Graph</span>.OptIn(Graph.OptIn.SUITE_PROCESS_STANDARD) +<span class="annotation">@Graph</span>.OptIn(Graph.OptIn.SUITE_PROCESS_COMPUTER) +<span class="directive">public</span> <span class="type">class</span> <span class="class">TinkerGraph</span> <span class="directive">implements</span> Graph {</code></pre> +</div> +</div> +<div class="paragraph"> +<p>Only include annotations for the suites the implementation will support. Note that implementing the suite, but +not specifying the appropriate annotation will prevent the suite from running (an obvious error message will appear +in this case when running the mis-configured suite).</p> +</div> +<div class="paragraph"> +<p>There are times when there may be a specific test in the suite that the implementation cannot support (despite the +features it implements) or should not otherwise be executed. It is possible for implementers to "opt-out" of a test +by using the <code>@Graph.OptOut</code> annotation. The following is an example of this annotation usage as taken from +<code>HadoopGraph</code>:</p> +</div> +<div class="listingblock"> +<div class="content"> +<pre class="CodeRay"><code class="java language-java"><span class="annotation">@Graph</span>.OptIn(Graph.OptIn.SUITE_PROCESS_STANDARD) +<span class="annotation">@Graph</span>.OptIn(Graph.OptIn.SUITE_PROCESS_COMPUTER) +<span class="annotation">@Graph</span>.OptOut( + test = <span class="string"><span class="delimiter">"</span><span class="content">org.apache.tinkerpop.gremlin.process.graph.step.map.MatchTest$Traversals</span><span class="delimiter">"</span></span>, + method = <span class="string"><span class="delimiter">"</span><span class="content">g_V_matchXa_hasXname_GarciaX__a_inXwrittenByX_b__a_inXsungByX_bX</span><span class="delimiter">"</span></span>,
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