Add constraint validation example with dummy data

.gitignore

 .idea/
 .DS_Store
 target/
-*.iml
+*.iml
\ No newline at end of file
+.project
+.classpath
+.factorypath
+.settings/
+bin/

README.md

@@ -3,7 +3,7 @@
 Make sure java 17 is installed.
 Make sure that Maven 3.8.3 is installed on your computer with `mvn --version`. If it is not, follow the instructions here: https://maven.apache.org/install.html.
 
-Test that things are up and running and can work on your machine. Run mvn package in the kg-shape-project directory, and you should see a build success message.
+Test that things are up and running and can work on your machine. Run `mvn package` in the kg-shape-project directory, and you should see a build success message.
 Then from the same directory, in the command line run:
 
 `java -cp target/kg-shape-project-1.0-SNAPSHOT.jar com.kgshape.app.App`

src/main/java/com/kgshape/app/Constraints.java

+package com.kgshape.app;
+
+import org.apache.jena.datatypes.RDFDatatype;
+import org.apache.jena.graph.Graph;
+import org.apache.jena.rdf.model.*;
+import org.apache.jena.shex.*;
+import org.apache.jena.shex.sys.ShexLib;
+import org.apache.jena.sparql.core.DatasetGraphFactory;
+
+import java.text.DateFormat;
+import java.util.Calendar;
+import java.util.Date;
+
+public class Constraints {
+
+    public static void main( String[] args ) {
+        // Create schema (these are the actual constraints that we've defined)
+        String shapeString = """
+                PREFIX :       <http://example.org/>
+                PREFIX schema: <http://example.org/>
+                PREFIX xsd:  <http://www.w3.org/2001/XMLSchema#>
+
+                :User IRI {\s
+                 schema:name          xsd:string  ;
+                 schema:lastName      xsd:string  ;
+                 schema:birthDate     xsd:date?  ;
+                 schema:age           xsd:long?  ;
+                }""";
+        ShexSchema shapes = Shex.schemaFromString(shapeString);
+
+        // Create the shape map; this will define which parts of our graph should be checked against which parts of our schema
+        String shapeMapString = "<http://example.org/alice> @<http://example.org/User>, <http://example.org/bob> @<http://example.org/User>";
+        String baseUrl= "http://example.org/";
+        ShexMap shapeMap = Shex.shapeMapFromString(shapeMapString, baseUrl);
+
+        // Create some dummy data; in our real implementation we will have a model from a sparql query
+        Model model = ModelFactory.createDefaultModel();
+
+        String personURI = "http://example.org/alice";
+        Resource alice = model.createResource(personURI);
+        Property nameProperty = model.createProperty("http://example.org/", "name");
+        Property lastNameProperty = model.createProperty("http://example.org/", "lastName");
+        Property dateProperty = model.createProperty("http://example.org/", "date");
+        Property ageProperty = model.createProperty("http://example.org/", "age");
+        Property extraProperty = model.createProperty("http://example.org/", "extra");
+
+        String name = "Alice";
+        alice.addProperty(nameProperty, name);
+        alice.addProperty(lastNameProperty, "Sumin");
+        alice.addProperty(dateProperty, "1980-03-10");
+        alice.addLiteral(ageProperty, 100);
+
+        String bobURI = "http://example.org/bob";
+        Resource bob = model.createResource(bobURI);
+        String bobName = "Bob";
+        bob.addProperty(nameProperty, bobName);
+        bob.addProperty(lastNameProperty, "Sumin2");
+        bob.addLiteral(ageProperty, 10);
+        // todo this type checking for date doesn't work.
+        bob.addLiteral(dateProperty, "notADate");
+        // Note: having an extra property that isn't defined in the shape does not break anything
+        bob.addProperty(extraProperty, "x");
+
+        Resource userGraph = model.createResource(baseUrl+"User");
+        Graph g =DatasetGraphFactory.create().getGraph(userGraph.asNode());
+        g.add(alice.getProperty(nameProperty).asTriple());
+        g.add(alice.getProperty(lastNameProperty).asTriple());
+        g.add(alice.getProperty(dateProperty).asTriple());
+        g.add(alice.getProperty(ageProperty).asTriple());
+        g.add(bob.getProperty(nameProperty).asTriple());
+        g.add(bob.getProperty(lastNameProperty).asTriple());
+        g.add(bob.getProperty(dateProperty).asTriple());
+        g.add(bob.getProperty(ageProperty).asTriple());
+
+        ShexReport report = ShexValidator.get().validate(g, shapes, shapeMap);
+
+        // Print report
+        ShexLib.printReport(report);
+    }
+}