Use isEmpty().

commons-rdf-api/src/main/java/org/apache/commons/rdf/api/Dataset.java

@@ -167,6 +167,15 @@ default void close() throws Exception {
      */
     Stream<BlankNodeOrIRI> getGraphNames();
 
+    /**
+     * Tests if this is empty.
+     * 
+     * @return true if this is empty.
+     */
+    default boolean isEmpty() {
+        return size() == 0;
+    }
+
     /**
      * Remove a concrete quad from the dataset.
      *
@@ -351,4 +360,5 @@ default Iterable<Quad> iterate(final Optional<BlankNodeOrIRI> graphName, final B
             final RDFTerm object) throws ConcurrentModificationException, IllegalStateException {
         return ((Stream<Quad>) stream(graphName, subject, predicate, object))::iterator;
     }
+
 }

commons-rdf-api/src/main/java/org/apache/commons/rdf/api/Graph.java

@@ -204,6 +204,15 @@ default Stream<? extends Triple> getTriples(final BlankNodeOrIRI subject, final
         return stream(subject, predicate, object);
     }
 
+    /**
+     * Tests if this is empty.
+     * 
+     * @return true if this is empty.
+     */
+    default boolean isEmpty() {
+        return size() == 0;
+    }
+
     /**
      * Gets an Iterable for iterating over all triples in the graph.
      * <p>
@@ -295,4 +304,5 @@ default Iterable<Triple> iterate(final BlankNodeOrIRI subject, final IRI predica
             throws ConcurrentModificationException, IllegalStateException {
         return ((Stream<Triple>) stream(subject, predicate, object))::iterator;
     }
+
 }

commons-rdf-api/src/test/java/org/apache/commons/rdf/api/AbstractDatasetTest.java

@@ -129,7 +129,7 @@ public void size() throws Exception {
 
     @Test
     public void iterate() throws Exception {
-        Assume.assumeTrue(dataset.size() > 0);
+        Assume.assumeFalse(dataset.isEmpty());
         final List<Quad> quads = new ArrayList<>();
         for (final Quad t : dataset.iterate()) {
             quads.add(t);

commons-rdf-api/src/test/java/org/apache/commons/rdf/api/AbstractGraphTest.java

@@ -135,7 +135,7 @@ public void createGraphAndAdd() {
 
     @Test
     public void size() throws Exception {
-        assertTrue(graph.size() > 0);
+        assertFalse(graph.isEmpty());
         Assume.assumeNotNull(bnode1, bnode2, aliceName, bobName, secretClubName, companyName, bobNameTriple);
         // Can only reliably predict size if we could create all triples
         assertEquals(8, graph.size());
@@ -144,7 +144,7 @@ public void size() throws Exception {
     @Test
     public void iterate() throws Exception {
 
-        Assume.assumeTrue(graph.size() > 0);
+        Assume.assumeFalse(graph.isEmpty());
 
         final List<Triple> triples = new ArrayList<>();
         for (final Triple t : graph.iterate()) {

commons-rdf-simple/src/test/java/org/apache/commons/rdf/simple/experimental/AbstractRDFParserTest.java

@@ -89,12 +89,12 @@ public void guessRDFSyntax() throws Exception {
         assertFalse(AbstractRDFParser.guessRDFSyntax(testXml).isPresent());
     }
 
-    private void checkGraph(final Graph g) throws Exception {
-        assertTrue(g.size() > 0);
+    private void checkGraph(final Graph graph) throws Exception {
+        assertFalse(graph.isEmpty());
         final IRI greeting = factory.createIRI("http://example.com/greeting");
         // Should only have parsed once!
-        assertEquals(1, g.stream(null, greeting, null).count());
-        final Triple triple = g.stream(null, greeting, null).findAny().get();
+        assertEquals(1, graph.stream(null, greeting, null).count());
+        final Triple triple = graph.stream(null, greeting, null).findAny().get();
         assertTrue(triple.getSubject() instanceof IRI);
         final IRI parsing = (IRI) triple.getSubject();
         assertTrue(parsing.getIRIString().startsWith("urn:uuid:"));
@@ -108,12 +108,12 @@ private void checkGraph(final Graph g) throws Exception {
         assertEquals(Types.XSD_STRING, literal.getDatatype());
 
         // Check uniqueness of properties that are always present
-        assertEquals(1, g.stream(null, factory.createIRI("http://example.com/source"), null).count());
+        assertEquals(1, graph.stream(null, factory.createIRI("http://example.com/source"), null).count());
 
         // Check optional properties that are unique
-        assertTrue(2 > g.stream(null, factory.createIRI("http://example.com/base"), null).count());
-        assertTrue(2 > g.stream(null, factory.createIRI("http://example.com/contentType"), null).count());
-        assertTrue(2 > g.stream(null, factory.createIRI("http://example.com/contentTypeSyntax"), null).count());
+        assertTrue(2 > graph.stream(null, factory.createIRI("http://example.com/base"), null).count());
+        assertTrue(2 > graph.stream(null, factory.createIRI("http://example.com/contentType"), null).count());
+        assertTrue(2 > graph.stream(null, factory.createIRI("http://example.com/contentTypeSyntax"), null).count());
     }
 
     @Test