[New] Add function add-days

s-pipes-core/src/main/java/cz/cvut/spipes/function/time/AddDays.java

@@ -0,0 +1,60 @@
+package cz.cvut.spipes.function.time;
+
+import cz.cvut.spipes.function.ValueFunction;
+import org.apache.jena.datatypes.RDFDatatype;
+import org.apache.jena.datatypes.xsd.XSDDatatype;
+import org.apache.jena.datatypes.xsd.impl.XSDDateType;
+import org.apache.jena.graph.Node;
+import org.apache.jena.sparql.expr.NodeValue;
+import org.apache.jena.sparql.function.FunctionEnv;
+import org.topbraid.spin.arq.AbstractFunction2;
+
+import java.time.LocalDate;
+import java.util.Optional;
+
+/**
+ * Extend specified `date` by number of `days`. Return typed literal with same datatype.
+ * Currently, supports only xsd:date datatype.
+ */
+public class AddDays extends AbstractFunction2 implements ValueFunction {
+
+
+    private static final String TYPE_IRI = "http://onto.fel.cvut.cz/ontologies/lib/function/time/add-days";
+
+    @Override
+    public String getTypeURI() {
+        return TYPE_IRI;
+    }
+
+    @Override
+    protected NodeValue exec(Node date, Node days, FunctionEnv env) {
+
+        Long daysToAdd = getDays(days);
+
+        if (getDatatype(date).equals(XSDDatatype.XSDdate) && daysToAdd != null) {
+
+            String newDate = LocalDate.parse(date.getLiteral().getValue().toString()).plusDays(daysToAdd).toString();
+
+            return NodeValue.makeNode(newDate, XSDDatatype.XSDdate);
+        }
+
+        return null;
+    }
+
+    private Long getDays(Node days) {
+        return Optional.of(days)
+            .filter(Node::isLiteral)
+            .filter(n -> n.getLiteralValue() instanceof Integer)
+            .map(n -> ((Integer) n.getLiteralValue()).longValue())
+            .orElse(null);
+    }
+
+    RDFDatatype getDatatype(Node date) {
+
+        return Optional.of(date)
+            .filter(Node::isLiteral)
+            .filter(n -> n.getLiteralDatatype() instanceof XSDDateType)
+            .map(Node::getLiteralDatatype)
+            .orElse(null);
+    }
+}

s-pipes-core/src/test/java/cz/cvut/spipes/function/time/AddDaysTest.java

@@ -0,0 +1,33 @@
+package cz.cvut.spipes.function.time;
+
+import org.apache.jena.datatypes.xsd.XSDDatatype;
+import org.apache.jena.graph.Node;
+import org.apache.jena.sparql.expr.NodeValue;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class AddDaysTest {
+
+    @Test
+    public void execReturnsTimeFromPast() {
+
+        AddDays addDays = new AddDays();
+        Node date = getDateNode("2022-01-01").asNode();
+        Node days = NodeValue.makeNodeDecimal("-1").asNode();
+
+        NodeValue returnedDate = addDays.exec(date, days, null);
+
+        NodeValue expectedDate = getDateNode("2021-12-31");
+        assertEquals(expectedDate, returnedDate);
+    }
+
+
+    private NodeValue getDateNode(String date) {
+        return NodeValue.makeNode(
+            date,
+            null,
+            XSDDatatype.XSDdate.getURI()
+        );
+    }
+}