Data class annotations

The following table lists the annotations that can be used on data classes and provides links to information and examples in this guide. The table is sorted in ascending alphabetical order by annotation name.

Data class annotations used in this guide
Annotation name	Annotation applies to¹	What it does	Where it is shown in this guide
DynamoDbAtomicCounter	attribute²	Increments a tagged numerical attribute each time a record is written to the database.	Introduction and discussion.
DynamoDbAttribute	attribute	Defines or renames a bean property that is mapped to a DynamoDB table attribute.	Initial discussion. Get started section—see Note. In MovieActor class In Query method examples.
DynamoDbAutoGeneratedTimestampAttribute	attribute	Updates a tagged attribute with a current timestamp every time the item is successfully written to the database	Introduction and discussion.
DynamoDbAutoGeneratedUuid	attribute	Generate a unique UUID (Universally Unique Identifier) for an attribute when a new record is written to the database.	Introduction and discussion.
DynamoDbBean	class	Marks a data class as mappable to a table schema.	First use on the Customer class in the Get started section. Several usages appear throughout the guide.
DynamoDbConvertedBy	attribute	Associates a custom `AttributeConverter` with the annotated attribute.	Initial discussion and example.
DynamoDbFlatten	attribute	Flattens all the attributes of a separate DynamoDB data class and adds them as top-level attributes to the record that is read and written to the database.	Initial discussion. Implications for other code.
DynamoDbIgnore	attribute	Results in the attribute remaining unmapped.	Initial discussion. Use in the ProductCatalog class.
DynamoDbIgnoreNulls	attribute	Prevents saving null attributes of nested DynamoDb objects.	Discussion and examples.
DynamoDbImmutable	class	Marks an immutable data class as mappable to a table schema.	Introduction to the annotation. Use in the ProductCatalog class. Use with Lombok.
DynamoDbPartitionKey	attribute	Marks an attribute as the primary partition key (hash key) of the DynamoDb table.	Initial usage on the Customer class in the Get started section. With Lombok.
DynamoDbPreserveEmptyObject	attribute	Specifies that if no data is present for the object mapped to the annotated attribute, the object should be initialized with all null fields.	Discussion and examples.
DynamoDbSecondaryPartitionKey	attribute	Marks an attribute as a partition key for a global secondary index.	Use in secondary indices and example. In Query method examples. In Lombok example With immutable classes.
DynamoDbSecondarySortKey	attribute	Marks an attribute as an optional sort key for a global or local secondary index.	Use in secondary indices and example. In Query method examples. In Lombok example. With immutable classes.
DynamoDbSortKey	attribute	Marks an attribute as the optional primary sort key (range key).	Get started section on Customer class. With immutable classes. In Lombok example. In Query method examples.
DynamoDbUpdateBehavior	attribute	Specifies the behavior when this attribute is updated as part of an 'update' operation such as UpdateItem.	Introduction and example.
DynamoDbVersionAttribute	attribute	Increments an item version number.	Introduction and discussion.

¹You can apply an attribute-level annotations to the getter or setter, but not both. This guide shows annotations on getters.

²The term property is normally used for a value encapsulated in a JavaBean data class. However, this guide uses the term attribute instead, to be consistent with the terminology used by DynamoDB.

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