Better throw a NoSuchElementException if no more elements are available because parser has been closed

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1509395 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/csv/CSVParser.java

@@ -381,8 +381,12 @@ public class CSVParser implements Iterable<CSVRecord>, Closeable {
     }
 
     /**
-     * Returns an iterator on the records. IOExceptions occurring during the iteration are wrapped in a
+     * Returns an iterator on the records.
+     *
+     * <p>IOExceptions occurring during the iteration are wrapped in a
      * RuntimeException.
+     * If the parser is closed a call to {@code next()} will throw a
+     * NoSuchElementException.</p>
      */
     public Iterator<CSVRecord> iterator() {
         return new Iterator<CSVRecord>() {
@@ -410,7 +414,7 @@ public class CSVParser implements Iterable<CSVRecord>, Closeable {
 
             public CSVRecord next() {
                 if (CSVParser.this.isClosed()) {
-                    return null;
+                    throw new NoSuchElementException("CSVParser has been closed");
                 }
                 CSVRecord next = this.current;
                 this.current = null;

src/test/java/org/apache/commons/csv/CSVParserTest.java

@@ -394,7 +394,7 @@ public class CSVParserTest {
         assertEquals(4, records.size());
     }
 
-    @Test
+    @Test(expected = NoSuchElementException.class)
     public void testClose() throws Exception {
         final Reader in = new StringReader("# comment\na,b,c\n1,2,3\nx,y,z");
         final CSVParser parser = CSVFormat.DEFAULT.withCommentStart('#').withHeader().parse(in);
@@ -402,9 +402,7 @@ public class CSVParserTest {
         assertTrue(records.hasNext());
         parser.close();
         assertFalse(records.hasNext());
-        assertNull(records.next());
-        assertFalse(records.hasNext());
-        assertNull(records.next());
+        records.next();
     }
 
     @Test