Types

Typed fields are at the heart of Tessellate.

tess supports all native Java primitive types (long and Long, etc.). And additional coercive types.

Java Built-in

Object types are nullable. Primitives numbers coerce to zero (0).

When declaring a field with a type, use one of the following values depending on if null values are permitted.

String: null or any String value.
int: null coerced to 0.
Integer: null ok.
long: null coerced to 0
Long: null ok.
float: null coerced to 0
Float: null ok.
double: null coerced to 0
Double: null ok.
boolean: null coerced to false
Boolean: null ok.

Coercive

Some types are canonically a custom or special Java type, but also have metadata associated with them.

These type take the form type[|metadata] where the optional metadata can be a format string, in the case of the temporal types.

Instant|format: Canonically a java.time.Instant. Supports nanos precision, format defaults to ISO-8601 instant format, e.g. 2011-12-03T10:15:30Z
DateTime|format: Canonically a Long, format defaults to yyyy-MM-dd HH:mm:ss.SSSSSS z.
json: Canonically a com.fasterxml.jackson.databind.JsonNode values, nested objects, and arrays.

When reading source data, fields can be parsed and coerced into specific types, as declared, or when using formats like Parquet, type information will be inherited.

When writing to a sink, the fields and any type metadata will be used to inform how the output is rendered or written.

In the case of Parquet, an Instant will be stored as a native Parquet timestamp with appropriate metadata for specifying the precision. When a Parquet file is read by tools like AWS Athena, the timestamp metadata will be honored.