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Posted to commits@jena.apache.org by bu...@apache.org on 2018/01/12 16:45:53 UTC
svn commit: r1023749 - in /websites/staging/jena/trunk/content: ./
documentation/query/javascript-functions.html
Author: buildbot
Date: Fri Jan 12 16:45:53 2018
New Revision: 1023749
Log:
Staging update by buildbot for jena
Added:
websites/staging/jena/trunk/content/documentation/query/javascript-functions.html
Modified:
websites/staging/jena/trunk/content/ (props changed)
Propchange: websites/staging/jena/trunk/content/
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+++ cms:source-revision Fri Jan 12 16:45:53 2018
@@ -1 +1 @@
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Added: websites/staging/jena/trunk/content/documentation/query/javascript-functions.html
==============================================================================
--- websites/staging/jena/trunk/content/documentation/query/javascript-functions.html (added)
+++ websites/staging/jena/trunk/content/documentation/query/javascript-functions.html Fri Jan 12 16:45:53 2018
@@ -0,0 +1,313 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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+ <h1 class="title">ARQ - JavaScript SPARQL Functions</h1>
+ <style type="text/css">
+/* The following code is added by mdx_elementid.py
+ It was originally lifted from http://subversion.apache.org/style/site.css */
+/*
+ * Hide class="elementid-permalink", except when an enclosing heading
+ * has the :hover property.
+ */
+.headerlink, .elementid-permalink {
+ visibility: hidden;
+}
+h2:hover > .headerlink, h3:hover > .headerlink, h1:hover > .headerlink, h6:hover > .headerlink, h4:hover > .headerlink, h5:hover > .headerlink, dt:hover > .elementid-permalink { visibility: visible }</style>
+<p>ARQ supports (Jena v3.7.0 onwards) writing
+<a href="https://www.w3.org/TR/sparql11-query/#extensionFunctions">custom SPARQL functions</a>
+in JavaScript. These functions can be used in FILTER and for calulatinfg
+values for BIND and AS in SELECT expressions.</p>
+<p>For convenience, XSD datatypes for strings, numbers and booleans are
+comverted to the native JavaScript datatypes. RDFterm that do not fit
+easily into JavaScript datatypes are handled with a object class <code>NV</code>.</p>
+<h2 id="loading-javascript-functions">Loading JavaScript functions<a class="headerlink" href="#loading-javascript-functions" title="Permanent link">¶</a></h2>
+<p>JavaScript is loaded from an external file using the context setting
+"http://jena.apache.org/ARQ#js-library". This can be written as
+<code>arq:js-library</code> for commands and Fuseki configuation files.</p>
+<p>Example:</p>
+<div class="codehilite"><pre><span class="n">sparql</span> <span class="o">--</span><span class="n">set</span> <span class="n">arq</span><span class="p">:</span><span class="n">js</span><span class="o">-</span><span class="n">library</span><span class="p">=</span><span class="n">SomeFile</span><span class="p">.</span><span class="n">js</span> <span class="o">--</span><span class="n">data</span> <span class="p">...</span> <span class="o">--</span><span class="n">query</span> <span class="p">...</span>
+</pre></div>
+
+
+<p>will execute omn teghdata with the JavaScript functions from file
+"SomeFile.js" available.</p>
+<p>JavScript functions cammn also be from a string directly from within Java using constant
+<code>ARQ.symJavaScriptFunctions</code> ("http://jena.apache.org/ARQ#js-functions").</p>
+<h2 id="using-javascript-functions">Using JavaScript functions<a class="headerlink" href="#using-javascript-functions" title="Permanent link">¶</a></h2>
+<p>SPARQL functions implemented in JavaScript are autoatica called when a
+URI starting "http://jena.apache.org/ARQ/jsFunction#" used.</p>
+<p>This can conveniently be abbreviated by:</p>
+<div class="codehilite"><pre><span class="n">PREFIX</span> <span class="n">js</span><span class="p">:</span> <span class="o"><</span><span class="n">http</span><span class="p">:</span><span class="o">//</span><span class="n">jena</span><span class="p">.</span><span class="n">apache</span><span class="p">.</span><span class="n">org</span><span class="o">/</span><span class="n">ARQ</span><span class="o">/</span><span class="n">jsFunction</span>#<span class="o">></span>
+</pre></div>
+
+
+<h3 id="arguments-and-function-results">Arguments and Function Results<a class="headerlink" href="#arguments-and-function-results" title="Permanent link">¶</a></h3>
+<p><code>xsd:string</code> (a string with no language tag), any XSD numbers
+(integer, decimal, float, double and all the derived types) are
+converted to JavaScript string, number and boolean respectively.</p>
+<p>SPARQL functions must return a value. When a function returns a value,
+it can be one of these JavaScript natbve dadatypes, in which case the
+reverse conversion is applied back to XSD datatypes.</p>
+<p>For numbers, the conversion is back to <code>xsd:integer</code> (if it has no
+fractional part) or <code>xsd:double</code>.</p>
+<p>The JavaScript fucntion can also create <code>NodeValue</code> (or <code>NV</code>) objects
+for other datatypes.</p>
+<p>URIs are passed as <code>NV</code> object and evaluate in JavaScript to a string.</p>
+<p>The class <code>NV</code> is used for all other RDF terms (including URIs).</p>
+<p>Returning JavaScript <code>null</code> is the error indicator and a SPARQL
+expression error (<code>ExprEvalException</code>) is raised, like any other
+expression error in SPARQL. That in turn will cause the whole
+expression the function was involved in to evaluate to an error (unelss
+a special form like <code>COALESCE</code> is used). In a <code>FILTER</code> that typcially
+makes the filter evaluate as "false".</p>
+<h2 id="example">Example<a class="headerlink" href="#example" title="Permanent link">¶</a></h2>
+<p>Suppose "functions.js" contains code to camel case words in a string.
+For example, "some words to process " becomes "someWordsToProcess".</p>
+<div class="codehilite"><pre><span class="c1">// CamelCase a string</span>
+<span class="c1">// Words to be combined are separated by a space in the string.</span>
+
+<span class="k">function</span> <span class="n">toCamelCase</span><span class="p">(</span><span class="n">str</span><span class="p">)</span> <span class="p">{</span>
+ <span class="k">return</span> <span class="n">str</span><span class="p">.</span><span class="n">split</span><span class="p">(</span><span class="sc">' '</span><span class="p">)</span>
+ <span class="p">.</span><span class="n">map</span><span class="p">(</span><span class="n">cc</span><span class="p">)</span>
+ <span class="p">.</span><span class="k">join</span><span class="p">('');</span>
+<span class="p">}</span>
+
+<span class="k">function</span> <span class="n">ucFirst</span><span class="p">(</span><span class="n">word</span><span class="p">)</span> <span class="p">{</span>
+ <span class="k">return</span> <span class="n">word</span><span class="p">.</span><span class="n">charAt</span><span class="p">(</span><span class="mh">0</span><span class="p">).</span><span class="n">toUpperCase</span><span class="p">()</span> <span class="o">+</span> <span class="n">word</span><span class="p">.</span><span class="n">slice</span><span class="p">(</span><span class="mh">1</span><span class="p">).</span><span class="n">toLowerCase</span><span class="p">();</span>
+<span class="p">}</span>
+
+<span class="k">function</span> <span class="n">lcFirst</span><span class="p">(</span><span class="n">word</span><span class="p">)</span> <span class="p">{</span>
+ <span class="k">return</span> <span class="n">word</span><span class="p">.</span><span class="n">toLowerCase</span><span class="p">();</span>
+<span class="p">}</span>
+
+<span class="k">function</span> <span class="n">cc</span><span class="p">(</span><span class="n">word</span><span class="p">,</span><span class="n">index</span><span class="p">)</span> <span class="p">{</span>
+ <span class="k">return</span> <span class="p">(</span><span class="n">index</span> <span class="o">==</span> <span class="mh">0</span><span class="p">)</span> <span class="o">?</span> <span class="n">lcFirst</span><span class="p">(</span><span class="n">word</span><span class="p">)</span> <span class="o">:</span> <span class="n">ucFirst</span><span class="p">(</span><span class="n">word</span><span class="p">);</span>
+<span class="p">}</span>
+</pre></div>
+
+
+<p>and the query <code>Q.rq</code></p>
+<div class="codehilite"><pre><span class="n">PREFIX</span> <span class="n">js</span><span class="p">:</span> <span class="o"><</span><span class="n">http</span><span class="p">:</span><span class="o">//</span><span class="n">jena</span><span class="p">.</span><span class="n">apache</span><span class="p">.</span><span class="n">org</span><span class="o">/</span><span class="n">ARQ</span><span class="o">/</span><span class="n">jsFunction</span>#<span class="o">></span>
+
+<span class="n">SELECT</span> ?<span class="n">input</span> <span class="p">(</span><span class="n">js</span><span class="p">:</span><span class="n">toCamelCase</span><span class="p">(</span>?<span class="n">input</span><span class="p">)</span> <span class="n">AS</span> ?<span class="n">X</span><span class="p">)</span>
+<span class="p">{</span>
+ <span class="n">VALUES</span> ?<span class="n">input</span> <span class="p">{</span> "<span class="n">some</span> <span class="n">words</span> <span class="n">to</span> <span class="n">process</span>" <span class="p">}</span>
+<span class="p">}</span>
+</pre></div>
+
+
+<p>which can be executed with:</p>
+<div class="codehilite"><pre><span class="n">sparql</span> <span class="o">--</span><span class="n">set</span> <span class="n">arq</span><span class="p">:</span><span class="n">js</span><span class="o">-</span><span class="n">library</span><span class="p">=</span><span class="n">SomeFile</span><span class="p">.</span><span class="n">js</span> <span class="o">--</span><span class="n">query</span> <span class="n">Q</span><span class="p">.</span><span class="n">rq</span>
+</pre></div>
+
+
+<p>to result in</p>
+<div class="codehilite"><pre><span class="o">--------------------------------------------------</span>
+<span class="o">|</span> <span class="n">input</span> <span class="o">|</span> <span class="n">X</span> <span class="o">|</span>
+<span class="o">==================================================</span>
+<span class="o">|</span> "<span class="n">some</span> <span class="n">words</span> <span class="n">to</span> <span class="n">process</span>" <span class="o">|</span> "<span class="n">someWordsToProcess</span>" <span class="o">|</span>
+<span class="o">--------------------------------------------------</span>
+</pre></div>
+
+
+<h2 id="use-with-fuseki">Use with Fuseki<a class="headerlink" href="#use-with-fuseki" title="Permanent link">¶</a></h2>
+<p>The content seeting can be provided on the command line starting the
+server, for example:</p>
+<div class="codehilite"><pre><span class="n">fuseki</span> <span class="o">--</span><span class="n">set</span> <span class="n">arq</span><span class="p">:</span><span class="n">js</span><span class="o">-</span><span class="n">library</span><span class="p">=</span><span class="n">functions</span><span class="p">.</span><span class="n">js</span> <span class="o">--</span><span class="n">mem</span> <span class="o">/</span><span class="n">ds</span>
+</pre></div>
+
+
+<p>or it can be specificied in the server coinfiguration file <code>config.ttl</code>:</p>
+<div class="codehilite"><pre><span class="n">PREFIX</span> <span class="p">:</span> <span class="o"><</span>#<span class="o">></span>
+<span class="n">PREFIX</span> <span class="n">fuseki</span><span class="p">:</span> <span class="o"><</span><span class="n">http</span><span class="p">:</span><span class="o">//</span><span class="n">jena</span><span class="p">.</span><span class="n">apache</span><span class="p">.</span><span class="n">org</span><span class="o">/</span><span class="n">fuseki</span>#<span class="o">></span>
+<span class="n">PREFIX</span> <span class="n">rdf</span><span class="p">:</span> <span class="o"><</span><span class="n">http</span><span class="p">:</span><span class="o">//</span><span class="n">www</span><span class="p">.</span><span class="n">w3</span><span class="p">.</span><span class="n">org</span><span class="o">/</span>1999<span class="o">/</span>02<span class="o">/</span>22<span class="o">-</span><span class="n">rdf</span><span class="o">-</span><span class="n">syntax</span><span class="o">-</span><span class="n">ns</span>#<span class="o">></span>
+<span class="n">PREFIX</span> <span class="n">rdfs</span><span class="p">:</span> <span class="o"><</span><span class="n">http</span><span class="p">:</span><span class="o">//</span><span class="n">www</span><span class="p">.</span><span class="n">w3</span><span class="p">.</span><span class="n">org</span><span class="o">/</span>2000<span class="o">/</span>01<span class="o">/</span><span class="n">rdf</span><span class="o">-</span><span class="n">schema</span>#<span class="o">></span>
+<span class="n">PREFIX</span> <span class="n">ja</span><span class="p">:</span> <span class="o"><</span><span class="n">http</span><span class="p">:</span><span class="o">//</span><span class="n">jena</span><span class="p">.</span><span class="n">hpl</span><span class="p">.</span><span class="n">hp</span><span class="p">.</span><span class="n">com</span><span class="o">/</span>2005<span class="o">/</span>11<span class="o">/</span><span class="n">Assembler</span>#<span class="o">></span>
+
+<span class="p">[]</span> <span class="n">rdf</span><span class="p">:</span><span class="n">type</span> <span class="n">fuseki</span><span class="p">:</span><span class="n">Server</span> <span class="p">;</span>
+ # <span class="n">Set</span> <span class="n">the</span> <span class="n">server</span><span class="o">-</span><span class="n">wide</span> <span class="n">context</span>
+ <span class="n">ja</span><span class="p">:</span><span class="n">context</span> <span class="p">[</span>
+ <span class="n">ja</span><span class="p">:</span><span class="n">cxtName</span> "<span class="n">arq</span><span class="p">:</span><span class="n">js</span><span class="o">-</span><span class="n">library</span>" <span class="p">;</span>
+ <span class="n">ja</span><span class="p">:</span><span class="n">cxtValue</span> "<span class="o">/</span><span class="n">home</span><span class="o">/</span><span class="n">afs</span><span class="o">/</span><span class="n">tmp</span><span class="o">/</span><span class="n">JSF</span><span class="o">/</span><span class="n">functions</span><span class="p">.</span><span class="n">js</span>"
+ <span class="p">]</span> <span class="p">;</span>
+<span class="p">.</span>
+
+<span class="o"><</span>#<span class="n">service</span><span class="o">></span> <span class="n">rdf</span><span class="p">:</span><span class="n">type</span> <span class="n">fuseki</span><span class="p">:</span><span class="n">Service</span><span class="p">;</span>
+ <span class="n">rdfs</span><span class="p">:</span><span class="n">label</span> "<span class="n">Dataset</span>"<span class="p">;</span>
+ <span class="n">fuseki</span><span class="p">:</span><span class="n">name</span> "<span class="n">ds</span>"<span class="p">;</span>
+ <span class="n">fuseki</span><span class="p">:</span><span class="n">serviceQuery</span> "<span class="n">sparql</span>"<span class="p">;</span>
+ <span class="n">fuseki</span><span class="p">:</span><span class="n">dataset</span> <span class="o"><</span>#<span class="n">dataset</span><span class="o">></span> <span class="p">;</span>
+ <span class="p">.</span>
+
+<span class="o"><</span>#<span class="n">dataset</span><span class="o">></span> <span class="n">rdf</span><span class="p">:</span><span class="n">type</span> <span class="n">ja</span><span class="p">:</span><span class="n">DatasetTxnMem</span><span class="p">;</span>
+ <span class="n">ja</span><span class="p">:</span><span class="n">data</span> <span class="o"><</span><span class="n">file</span><span class="p">:</span><span class="n">D</span><span class="p">.</span><span class="n">trig</span><span class="o">></span><span class="p">;</span>
+<span class="p">.</span>
+</pre></div>
+
+
+<p>and used as:</p>
+<div class="codehilite"><pre><span class="n">fuseki</span> <span class="o">--</span><span class="n">conf</span> <span class="n">config</span><span class="p">.</span><span class="n">ttl</span>
+</pre></div>
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