Add documentation

Signed-off-by: Dinu John <[email protected]>

data-prepper-plugins/rds-source/src/main/java/org/opensearch/dataprepper/plugins/source/rds/datatype/impl/TemporalTypeHandler.java

@@ -12,6 +12,22 @@
 import java.time.format.DateTimeFormatter;
 import java.time.format.DateTimeParseException;
 
+/**
+ * Handles MySQL temporal data types (DATE, TIME, DATETIME, YEAR) conversion between binlog and S3 export formats.
+ *
+ * MySQL binlog represents temporal types as follows:
+ * - DATE: long value representing days since epoch (1970-01-01)
+ * - TIME: long value representing milliseconds since epoch (1970-01-01 00:00:00)
+ * - DATETIME: long value representing microseconds since epoch (1970-01-01 00:00:00)
+ * - YEAR: 4-digit year value (Example: 2024)
+ *
+ * S3 export formats:
+ * - DATE: "yyyy-MM-dd" (Example: "2024-01-15")
+ * - TIME: "HH:mm:ss" (Example: "14:30:00")
+ * - DATETIME: "yyyy-MM-dd HH:mm:ss[.SSSSSS]" (Example: "2024-01-15 14:30:00.123456")
+ *   Note: Fractional seconds are optional for DATETIME
+ * - YEAR: "yyyy" (Example: "2024")
+ */
 public class TemporalTypeHandler implements DataTypeHandler {
     private static final String MYSQL_DATE_FORMAT = "yyyy-MM-dd";
     private static final String MYSQL_TIME_FORMAT = "HH:mm:ss";