Merge remote-tracking branch 'rdf4j-doc/master' into GH-2333-merge-rd…

…f4j-doc-master

.gitmodules

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+[submodule "site/themes/hugo-solstice-theme"]
+	path = site/themes/hugo-solstice-theme
+	url = https://github.com/EclipseFdn/hugo-solstice-theme.git

examples/.settings/org.eclipse.jdt.ui.prefs

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+eclipse.preferences.version=1
+formatter_profile=_examples
+formatter_settings_version=12

examples/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.eclipse.rdf4j</groupId>
+    <artifactId>examples</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.eclipse.rdf4j</groupId>
+                <artifactId>rdf4j-bom</artifactId>
+                <version>2.1.4</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.eclipse.rdf4j</groupId>
+            <artifactId>rdf4j-runtime</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.eclipse.rdf4j</groupId>
+            <artifactId>rdf4j-queryresultio-text</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-simple</artifactId>
+            <version>1.7.10</version>
+            <scope>runtime</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.6.0</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                    <encoding>utf8</encoding>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

examples/src/main/java/org/eclipse/rdf4j/examples/function/PalindromeFunction.java

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+/*******************************************************************************
+ * Copyright (c) 2017 Eclipse RDF4J contributors.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Distribution License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *******************************************************************************/
+package org.eclipse.rdf4j.examples.function;
+
+import org.eclipse.rdf4j.model.Literal;
+import org.eclipse.rdf4j.model.Value;
+import org.eclipse.rdf4j.model.ValueFactory;
+import org.eclipse.rdf4j.query.algebra.evaluation.ValueExprEvaluationException;
+import org.eclipse.rdf4j.query.algebra.evaluation.function.Function;
+
+/**
+ * An example custom SPARQL function that detects palindromes
+ * 
+ * @author Jeen Broekstra
+ */
+public class PalindromeFunction implements Function {
+
+	// define a constant for the namespace of our custom function
+	public static final String NAMESPACE = "http://example.org/custom-function/";
+
+	/**
+	 * return the URI 'http://example.org/custom-function/palindrome' as a
+	 * String
+	 */
+	public String getURI() {
+		return NAMESPACE + "palindrome";
+	}
+
+	/**
+	 * Executes the palindrome function.
+	 *
+	 * @return A boolean literal representing true if the input argument is a
+	 *         palindrome, false otherwise.
+	 * @throws ValueExprEvaluationException
+	 *         if more than one argument is supplied or if the supplied argument
+	 *         is not a literal.
+	 */
+	public Value evaluate(ValueFactory valueFactory, Value... args)
+		throws ValueExprEvaluationException
+	{
+		// our palindrome function expects only a single argument, so throw an error
+		// if there's more than one
+		if (args.length != 1) {
+			throw new ValueExprEvaluationException(
+					"palindrome function requires" + "exactly 1 argument, got "
+							+ args.length);
+		}
+		Value arg = args[0];
+		// check if the argument is a literal, if not, we throw an error
+		if (!(arg instanceof Literal)) {
+			throw new ValueExprEvaluationException(
+					"invalid argument (literal expected): " + arg);
+		}
+
+		// get the actual string value that we want to check for palindrome-ness.
+		String label = ((Literal)arg).getLabel();
+		// we invert our string
+		String inverted = "";
+		for (int i = label.length() - 1; i >= 0; i--) {
+			inverted += label.charAt(i);
+		}
+		// a string is a palindrome if it is equal to its own inverse
+		boolean palindrome = inverted.equalsIgnoreCase(label);
+
+		// a function is always expected to return a Value object, so we
+		// return our boolean result as a Literal
+		return valueFactory.createLiteral(palindrome);
+	}
+}

examples/src/main/java/org/eclipse/rdf4j/examples/model/Example01BuildModel.java

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+/*******************************************************************************
+ * Copyright (c) 2016 Eclipse RDF4J contributors.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Distribution License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *******************************************************************************/
+package org.eclipse.rdf4j.examples.model;
+
+import org.eclipse.rdf4j.model.IRI;
+import org.eclipse.rdf4j.model.Model;
+import org.eclipse.rdf4j.model.Statement;
+import org.eclipse.rdf4j.model.ValueFactory;
+import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
+import org.eclipse.rdf4j.model.impl.TreeModel;
+import org.eclipse.rdf4j.model.vocabulary.FOAF;
+import org.eclipse.rdf4j.model.vocabulary.RDF;
+
+/**
+ * RDF Tutorial example 01: Building a simple RDF Model using Eclipse RDF4J
+ *
+ * @author Jeen Broekstra
+ */
+public class Example01BuildModel {
+
+	public static void main(String[] args) {
+
+		// We use a ValueFactory to create the building blocks of our RDF statements: IRIs, blank nodes
+		// and literals.
+		ValueFactory vf = SimpleValueFactory.getInstance();
+
+		// We want to reuse this namespace when creating several building blocks.
+		String ex = "http://example.org/";
+
+		// Create IRIs for the resources we want to add.
+		IRI picasso = vf.createIRI(ex, "Picasso");
+		IRI artist = vf.createIRI(ex, "Artist");
+
+		// Create a new, empty Model object.
+		Model model = new TreeModel();
+
+		// add our first statement: Picasso is an Artist
+		model.add(picasso, RDF.TYPE, artist);
+
+		// second statement: Picasso's first name is "Pablo".
+		model.add(picasso, FOAF.FIRST_NAME, vf.createLiteral("Pablo"));
+
+		// to see what's in our model, let's just print it to the screen
+		for(Statement st: model) {
+			System.out.println(st);
+		}
+	}
+}

examples/src/main/java/org/eclipse/rdf4j/examples/model/Example02BuildModel.java

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+/*******************************************************************************
+ * Copyright (c) 2016 Eclipse RDF4J contributors.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Distribution License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *******************************************************************************/
+package org.eclipse.rdf4j.examples.model;
+
+import org.eclipse.rdf4j.model.Model;
+import org.eclipse.rdf4j.model.Statement;
+import org.eclipse.rdf4j.model.util.ModelBuilder;
+import org.eclipse.rdf4j.model.vocabulary.FOAF;
+import org.eclipse.rdf4j.model.vocabulary.RDF;
+
+/**
+ * RDF Tutorial example 02: Building a simple RDF Model using the RDF4J ModelBuilder
+ *
+ * @author Jeen Broekstra
+ */
+public class Example02BuildModel {
+
+	public static void main(String[] args) {
+
+		// Create a new RDF model containing two statements by using a ModelBuilder
+		ModelBuilder builder = new ModelBuilder();
+		Model model = builder
+				.setNamespace("ex", "http://example.org/")
+				.subject("ex:Picasso")
+					.add(RDF.TYPE, "ex:Artist")		// Picasso is an Artist
+					.add(FOAF.FIRST_NAME, "Pablo") 	// his first name is "Pablo"
+				.build();
+
+		// To see what's in our model, let's just print it to the screen
+		for(Statement st: model) {
+			System.out.println(st);
+		}
+	}
+}

examples/src/main/java/org/eclipse/rdf4j/examples/model/Example03LiteralDatatypes.java

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+/*******************************************************************************
+ * Copyright (c) 2016, 2017 Eclipse RDF4J contributors.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Distribution License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *******************************************************************************/
+package org.eclipse.rdf4j.examples.model;
+
+import java.util.Date;
+
+import javax.xml.datatype.XMLGregorianCalendar;
+
+import org.eclipse.rdf4j.model.IRI;
+import org.eclipse.rdf4j.model.Literal;
+import org.eclipse.rdf4j.model.Model;
+import org.eclipse.rdf4j.model.Statement;
+import org.eclipse.rdf4j.model.Value;
+import org.eclipse.rdf4j.model.ValueFactory;
+import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
+import org.eclipse.rdf4j.model.util.ModelBuilder;
+import org.eclipse.rdf4j.model.vocabulary.XMLSchema;
+
+/**
+ * RDF Tutorial example 03: Datatyped literals
+ *
+ * @author Jeen Broekstra
+ */
+public class Example03LiteralDatatypes {
+
+	public static void main(String[] args) {
+
+		ValueFactory vf = SimpleValueFactory.getInstance();
+
+		// Create a new RDF model containing information about the painting "The Potato Eaters"
+		ModelBuilder builder = new ModelBuilder();
+		Model model = builder
+				.setNamespace("ex", "http://example.org/")
+				.subject("ex:PotatoEaters")
+					// this painting was created on April 1, 1885
+					.add("ex:creationDate", vf.createLiteral("1885-04-01T00:00:00Z", XMLSchema.DATETIME))
+					// You can also pass in a Java Date object directly: 
+				    //.add("ex:creationDate", new GregorianCalendar(1885, Calendar.APRIL, 1).getTime())
+
+					// the painting shows 5 people
+					.add("ex:peopleDepicted", 5)
+				.build();
+
+		// To see what's in our model, let's just print stuff to the screen
+		for(Statement st: model) {
+			// we want to see the object values of each property
+			IRI property = st.getPredicate();
+			Value value = st.getObject();
+			if (value instanceof Literal) {
+				Literal literal = (Literal)value;
+				System.out.println("datatype: " + literal.getDatatype());
+
+				// get the value of the literal directly as a Java primitive.
+				if (property.getLocalName().equals("peopleDepicted")) {
+					int peopleDepicted = literal.intValue();
+					System.out.println(peopleDepicted + " people are depicted in this painting");
+				}
+				else if (property.getLocalName().equals("creationDate")) {
+					XMLGregorianCalendar calendar = literal.calendarValue();
+					Date date = calendar.toGregorianCalendar().getTime();
+					System.out.println("The painting was created on " + date);
+				}
+
+				// you can also just get the lexical value (a string) without worrying about the datatype
+				System.out.println("Lexical value: '" + literal.getLabel() + "'");
+			}
+		}
+	}
+}

examples/src/main/java/org/eclipse/rdf4j/examples/model/Example04LanguageTags.java

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+/*******************************************************************************
+ * Copyright (c) 2016, 2017 Eclipse RDF4J contributors.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Distribution License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *******************************************************************************/
+package org.eclipse.rdf4j.examples.model;
+
+import org.eclipse.rdf4j.model.Literal;
+import org.eclipse.rdf4j.model.Model;
+import org.eclipse.rdf4j.model.Statement;
+import org.eclipse.rdf4j.model.Value;
+import org.eclipse.rdf4j.model.ValueFactory;
+import org.eclipse.rdf4j.model.impl.SimpleValueFactory;
+import org.eclipse.rdf4j.model.util.ModelBuilder;
+import org.eclipse.rdf4j.model.vocabulary.DC;
+
+/**
+ * RDF Tutorial example 04: Language tags
+ *
+ * @author Jeen Broekstra
+ */
+public class Example04LanguageTags {
+
+	public static void main(String[] args) {
+
+		ValueFactory vf = SimpleValueFactory.getInstance();
+
+		// Create a new RDF model containing some information about the painting "The Potato Eaters"
+		ModelBuilder builder = new ModelBuilder();
+		Model model = builder
+				.setNamespace("ex", "http://example.org/")
+				.subject("ex:PotatoEaters")
+					// In English, this painting is called "The Potato Eaters"
+				    .add(DC.TITLE, vf.createLiteral("The Potato Eaters", "en"))
+				    // In Dutch, it's called "De Aardappeleters"
+					.add(DC.TITLE,  vf.createLiteral("De Aardappeleters", "nl"))
+				.build();
+
+		// To see what's in our model, let's just print it to the screen
+		for(Statement st: model) {
+			// we want to see the object values of each statement
+			Value value = st.getObject();
+			if (value instanceof Literal) {
+				Literal title = (Literal)value;
+				System.out.println("language: " + title.getLanguage().orElse("unknown"));
+				System.out.println(" title: " + title.getLabel());
+			}
+		}
+	}
+}