Add CSVRecord.isSet(int) method (apache#52)

* Add CSVRecord.isSet(int) method

* Remove unnecessary unboxing

* Revert: Remove unnecessary unboxing

Author: 0x100

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

@@ -214,6 +214,17 @@ public boolean isSet(final String name) {
         return isMapped(name) && getHeaderMapRaw().get(name).intValue() < values.length;
     }
 
+    /**
+     * Checks whether a column with given index has a value.
+     *
+     * @param i
+     *         a column index (0-based)
+     * @return whether a column with given index has a value
+     */
+    public boolean isSet(final int i) {
+        return 0 <= i && i < values.length;
+    }
+
     /**
      * Returns an iterator over the values of this record.
      *

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

@@ -134,12 +134,22 @@ public void testIsMapped() {
     }
 
     @Test
-    public void testIsSet() {
+    public void testIsSetString() {
         assertFalse(record.isSet("first"));
         assertTrue(recordWithHeader.isSet("first"));
         assertFalse(recordWithHeader.isSet("fourth"));
     }
 
+    @Test
+    public void testIsSetInt() {
+        assertFalse(record.isSet(-1));
+        assertTrue(record.isSet(0));
+        assertTrue(record.isSet(2));
+        assertFalse(record.isSet(3));
+        assertTrue(recordWithHeader.isSet(1));
+        assertFalse(recordWithHeader.isSet(1000));
+    }
+
     @Test
     public void testIterator() {
         int i = 0;