Merge pull request #67 from waxxxd/master

Basic implementation for getCell with MissingCellPolicy.

src/main/java/com/monitorjbl/xlsx/impl/StreamingRow.java

@@ -150,7 +150,14 @@ public void setRowNum(int rowNum) {
    */
   @Override
   public Cell getCell(int cellnum, MissingCellPolicy policy) {
-    throw new NotSupportedException();
+	  StreamingCell cell = (StreamingCell) cellMap.get(cellnum);
+	  if (policy == Row.CREATE_NULL_AS_BLANK) {
+		  if (cell == null) return new StreamingCell(cellnum, rowIndex, false);
+
+	  } else if (policy == Row.RETURN_BLANK_AS_NULL) {
+		  if (cell.getCellType() == Cell.CELL_TYPE_BLANK) return null;
+	  }
+	  return cell;
   }
 
   /**

src/test/java/com/monitorjbl/xlsx/StreamingReaderTest.java

@@ -28,6 +28,7 @@
 import static org.hamcrest.core.Is.is;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
@@ -579,4 +580,30 @@ public void shouldIgnoreSpreadsheetDrawingRows() throws Exception {
       }
     }
   }
+
+	@Test
+	public void testShouldReturnNullForMissingCellPolicy_RETURN_BLANK_AS_NULL() throws Exception {
+  	  try (
+	    InputStream is = new FileInputStream(new File("src/test/resources/blank_cells.xlsx"));
+		StreamingReader reader = StreamingReader.builder()
+		    .read(is);
+		) {
+  	  	  Row row = reader.iterator().next();
+		  assertNotNull(row.getCell(0, Row.RETURN_BLANK_AS_NULL)); //Remain unchanged
+		  assertNull(row.getCell(1, Row.RETURN_BLANK_AS_NULL));
+		}
+	}
+
+	@Test
+	public void testShouldReturnBlankForMissingCellPolicy_CREATE_NULL_AS_BLANK() throws Exception {
+  	  try (
+	    InputStream is = new FileInputStream(new File("src/test/resources/null_cell.xlsx"));
+		StreamingReader reader = StreamingReader.builder()
+		    .read(is);
+		) {
+  	  	  Row row = reader.iterator().next();
+		  assertEquals("B1 is Null ->", row.getCell(0, Row.CREATE_NULL_AS_BLANK).getStringCellValue()); //Remain unchanged
+		  assertNotNull(row.getCell(1, Row.CREATE_NULL_AS_BLANK));
+		}
+	}
 }