Document that the list of header names will not contain null names.
Added a test to demonstrate missing null headers from the list.
diff --git a/src/main/java/org/apache/commons/csv/CSVParser.java b/src/main/java/org/apache/commons/csv/CSVParser.java
index 3803d96..c189dc4 100644
--- a/src/main/java/org/apache/commons/csv/CSVParser.java
+++ b/src/main/java/org/apache/commons/csv/CSVParser.java
@@ -555,6 +555,11 @@
* <p>
* The map keys are column names. The map values are 0-based indices.
* </p>
+ * <p>
+ * Note: The map can only provide a one-to-one mapping when the format did not
+ * contain null or duplicate column names.
+ * </p>
+ *
* @return a copy of the header map.
*/
public Map<String, Integer> getHeaderMap() {
@@ -577,8 +582,14 @@
/**
* Returns a read-only list of header names that iterates in column order.
+ * <p>
+ * Note: The list provides strings that can be used as keys in the header map.
+ * The list will not contain null column names if they were present in the input
+ * format.
+ * </p>
*
* @return read-only list of header names that iterates in column order.
+ * @see #getHeaderMap()
* @since 1.7
*/
public List<String> getHeaderNames() {
diff --git a/src/test/java/org/apache/commons/csv/CSVParserTest.java b/src/test/java/org/apache/commons/csv/CSVParserTest.java
index 6b0dfc3..582652f 100644
--- a/src/test/java/org/apache/commons/csv/CSVParserTest.java
+++ b/src/test/java/org/apache/commons/csv/CSVParserTest.java
@@ -725,6 +725,20 @@
}
@Test
+ public void testHeadersWithNullColumnName() throws IOException {
+ final Reader in = new StringReader("header1,null,header3\n1,2,3\n4,5,6");
+ final Iterator<CSVRecord> records = CSVFormat.DEFAULT
+ .withHeader()
+ .withNullString("null")
+ .withAllowMissingColumnNames()
+ .parse(in).iterator();
+ final CSVRecord record = records.next();
+ // Expect the null header to be missing
+ assertEquals(Arrays.asList("header1", "header3"), record.getParser().getHeaderNames());
+ assertEquals(2, record.getParser().getHeaderMap().size());
+ }
+
+ @Test
public void testIgnoreCaseHeaderMapping() throws Exception {
final Reader reader = new StringReader("1,2,3");
final Iterator<CSVRecord> records = CSVFormat.DEFAULT.withHeader("One", "TWO", "three").withIgnoreHeaderCase()
