indexFieldName property
A string that represents the name of an index field. CloudSearch supports regular index fields as well as dynamic fields. A dynamic field's name defines a pattern that begins or ends with a wildcard. Any document fields that don't map to a regular index field but do match a dynamic field's pattern are configured with the dynamic field's indexing options.
Regular field names begin with a letter and can contain the following characters: a-z (lowercase), 0-9, and _ (underscore). Dynamic field names must begin or end with a wildcard (*). The wildcard can also be the only character in a dynamic field name. Multiple wildcards, and wildcards embedded within a string are not supported.
The name score is reserved and cannot be used as a field name.
To reference a document's ID, you can use the name _id.
Implementation
final String indexFieldName;