merged from trunk @62336

git-svn-id: http://svn.research-infrastructures.eu/public/d4science/gcube/branches/data-access/streams/2.0@67188 82a268e6-3cf1-43bd-a215-b396298e98cf

pom.xml

@@ -9,7 +9,7 @@
 
 	<groupId>org.gcube.data.access</groupId>
 	<artifactId>streams</artifactId>
-	<version>2.0.0-SNAPSHOT</version>
+	<version>2.0.1-SNAPSHOT</version>
 
 
 	<name>Stream Library</name>

src/main/java/org/gcube/data/streams/LookAheadStream.java

@@ -25,9 +25,18 @@ public abstract class LookAheadStream<E> implements Stream<E> {
 
 	private FaultHandler handler = new RethrowHandler();
 
+	private static class NullOr<T> {
+		T element;
+		NullOr(T element) {
+			this.element=element;
+		}
+		T value() {
+			return element;
+		}
+	}
 	// iteration state
 	protected Boolean hasNext;
-	protected E element;
+	protected NullOr<E> element;
 	private RuntimeException failure;
 	
 	/**
@@ -63,7 +72,7 @@ public abstract class LookAheadStream<E> implements Stream<E> {
 			return false;
 
 		try {
-			this.element = delegateNext();
+			this.element = new NullOr<E>(delegateNext());
 			return true;
 		}
 		catch (RuntimeException failure) {
@@ -113,7 +122,7 @@ public abstract class LookAheadStream<E> implements Stream<E> {
 			else
 				throw new NoSuchElementException();
 		
-		return element;
+		return element.value();
 				
 	}
 	

src/main/java/org/gcube/data/streams/test/Utils.java

@@ -116,8 +116,7 @@ public class Utils {
 		//consume
 		while (stream.hasNext())
 			try {
-				if (stream.next()==null)
-					throw new AssertionError("hasNext() returns true but next() returns null");
+				stream.next();
 			}
 			catch(RuntimeException e) {
 				//ignore exceptions for this test

src/test/java/org/gcube/data/streams/RsStreamTest.java

@@ -25,7 +25,7 @@ public class RsStreamTest {
 	@Test
 	public void resultsetsMakeValidStreams() throws Exception {
 		
-		final List<String> elements = asList("1","2","3");
+		final List<String> elements = asList("1",null,"3");
 		
 		StreamProvider provider = new StreamProvider() {