[CSV-100] CSVParser: getHeaderMap throws NPE.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1524435 13f79535-47bb-0310-9956-ffa450edef68

Author: garydgregory

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

@@ -281,11 +281,11 @@ public long getCurrentLineNumber() {
      * Returns a copy of the header map that iterates in column order.
      * <p>
      * The map keys are column names. The map values are 0-based indices.
-     *
+     * </p>
      * @return a copy of the header map that iterates in column order.
      */
     public Map<String, Integer> getHeaderMap() {
-        return new LinkedHashMap<String, Integer>(this.headerMap);
+        return this.headerMap == null ? null : new LinkedHashMap<String, Integer>(this.headerMap);
     }
 
     /**

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

@@ -664,6 +664,12 @@ public void testGetHeaderMap() throws Exception {
         assertFalse(records.hasNext());
     }
 
+    @Test
+    public void testNoHeaderMap() throws Exception {
+        final CSVParser parser = CSVParser.parse("a,b,c\n1,2,3\nx,y,z", CSVFormat.DEFAULT);
+        Assert.assertNull(parser.getHeaderMap());
+    }
+
     @Test
     public void testGetLineNumberWithLF() throws Exception {
         this.validateLineNumbers(String.valueOf(LF));