Fix error parsing timestamp containing offset (#575)

The new pattern will parse timestamp containing zone ids or offsets.
It's also compatible with the subtle difference between ISO8601 and
RFC3339 (offsets with +00:00 and -00:00).

Author: fmachado

src/main/java/org/influxdb/impl/InfluxDBResultMapper.java

@@ -57,12 +57,12 @@ public class InfluxDBResultMapper {
 
   /**
    * When a query is executed without {@link TimeUnit}, InfluxDB returns the <tt>time</tt>
-   * column as an ISO8601 date.
+   * column as a RFC3339 date.
    */
-  private static final DateTimeFormatter ISO8601_FORMATTER = new DateTimeFormatterBuilder()
+  private static final DateTimeFormatter RFC3339_FORMATTER = new DateTimeFormatterBuilder()
     .appendPattern("yyyy-MM-dd'T'HH:mm:ss")
     .appendFraction(ChronoField.NANO_OF_SECOND, FRACTION_MIN_WIDTH, FRACTION_MAX_WIDTH, ADD_DECIMAL_POINT)
-    .appendPattern("X")
+    .appendZoneOrOffsetId()
     .toFormatter();
 
   /**
@@ -338,7 +338,7 @@ <T> boolean fieldValueModified(final Class<?> fieldType, final Field field, fina
     if (Instant.class.isAssignableFrom(fieldType)) {
       Instant instant;
       if (value instanceof String) {
-        instant = Instant.from(ISO8601_FORMATTER.parse(String.valueOf(value)));
+        instant = Instant.from(RFC3339_FORMATTER.parse(String.valueOf(value)));
       } else if (value instanceof Long) {
         instant = Instant.ofEpochMilli(toMillis((long) value, precision));
       } else if (value instanceof Double) {

src/test/java/org/influxdb/impl/InfluxDBResultMapperTest.java

@@ -441,6 +441,37 @@ void testToPOJOInheritance() {
     Assertions.assertEquals(subValue, result.get(0).subValue);
   }
 
+  @Test
+  public void testToPOJO_ticket573() {
+    // Given...
+    mapper.cacheMeasurementClass(MyCustomMeasurement.class);
+
+    List<String> columnList = Arrays.asList("time");
+    List<List<Object>> valuesList = Arrays.asList(
+      Arrays.asList("2015-08-17T19:00:00-05:00"), // Chicago (UTC-5)
+      Arrays.asList("2015-08-17T19:00:00.000000001-05:00"), // Chicago (UTC-5)
+      Arrays.asList("2000-01-01T00:00:00-00:00"),
+      Arrays.asList("2000-01-02T00:00:00+00:00")
+    );
+
+    QueryResult.Series series = new QueryResult.Series();
+    series.setColumns(columnList);
+    series.setValues(valuesList);
+
+    // When...
+    List<MyCustomMeasurement> result = new LinkedList<>();
+    mapper.parseSeriesAs(series, MyCustomMeasurement.class, result);
+
+    // Then...
+    Assertions.assertEquals(4, result.size(), "incorrect number of elemets");
+    // Note: RFC3339 timestamp with TZ from InfluxDB are parsed into an Instant (UTC)
+    Assertions.assertTrue(result.get(0).time.equals(Instant.parse("2015-08-18T00:00:00Z")));
+    Assertions.assertTrue(result.get(1).time.equals(Instant.parse("2015-08-18T00:00:00.000000001Z")));
+    // RFC3339 section 4.3 https://tools.ietf.org/html/rfc3339#section-4.3
+    Assertions.assertTrue(result.get(2).time.equals(Instant.parse("2000-01-01T00:00:00Z")));
+    Assertions.assertTrue(result.get(3).time.equals(Instant.parse("2000-01-02T00:00:00Z")));
+  }
+
 	@Measurement(name = "CustomMeasurement")
 	static class MyCustomMeasurement {