DDBEnhanced - Support to flatten a Map into top level attributes of the object

[anasatirbasa]

Added the facility of using an annotation that will flatten a map of attributes in a class,
similar to what @DynamoDbFlatten does for attributes from another class.

Description

Added a new annotation named DynamoDbFlattenMap that can be applied at method level for only a single map of attributes within a class (Map<String, String>). If used on multiple maps of attributes, the serialization will throw an exception.

Motivation and Context

#2542

Modifications

Followed the same approach as for DybamoDbFlatten annotation, that is used to flatten all the attributes of a separate DynamoDb bean that is stored in the current bean

Testing

The changes have already been tested by running the existing tests and also added new unit/integration tests for the new flow.

Test Coverage Checklist

Scenario	Done	Comments if Not Done
1. Different TableSchema Creation Methods
a. TableSchema.fromBean(Customer.class)	[x]
b. TableSchema.fromImmutableClass(Customer.class) for immutable classes	[x]
c. TableSchema.documentSchemaBuilder().build()	[ ]
d. StaticTableSchema.builder(Customer.class)	[x]
2. Nesting of Different TableSchema Types
a. @DynamoDbBean with nested @DynamoDbBean as NonNull	[x]
b. @DynamoDbBean with nested @DynamoDbImmutable as NonNull	[x]
c. @DynamoDbImmutable with nested @DynamoDbBean as NonNull	[x]
d. @DynamoDbBean with nested @DynamoDbBean as Null	[x]
e. @DynamoDbBean with nested @DynamoDbImmutable as Null	[x]
f. @DynamoDbImmutable with nested @DynamoDbBean as Null	[x]
3. CRUD Operations
a. scan()	[ ]
b. query()	[x]
c. updateItem()	[x]
d. putItem()	[x]
e. getItem()	[x]
f. deleteItem()	[ ]
g. batchGetItem()	[ ]
h. batchWriteItem()	[ ]
i. transactGetItems()	[ ]
j. transactWriteItems()	[ ]
4. Data Types and Null Handling
a. top-level null attributes	[x]
b. collections with null elements	[x]
c. maps with null values	[x]
d. conversion between null Java values and AttributeValue	[ ]
e. full serialization/deserialization cycle with null values	[ ]
5. AsyncTable and SyncTable
a. DynamoDbAsyncTable Testing	[ ]
b. DynamoDbTable Testing	[ ]
6. New/Modification in Extensions
a. Tables with Scenario in ScenarioSl No.1 (All table schemas are Must)	[ ]
b. Test with Default Values in Annotations	[ ]
c. Combination of Annotation and Builder passes extension	[ ]
7. New/Modification in Converters
a. Tables with Scenario in ScenarioSl No.1 (All table schemas are Must)	[ ]
b. Test with Default Values in Annotations	[ ]
c. Test All Scenarios from 1 to 5	[ ]

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed
• I have added a changelog entry. Adding a new entry must be accomplished by running the scripts/new-change script and following the instructions. Commit the new file created by the script in .changes/next-release with your changes.
• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

• I confirm that this pull request can be released under the Apache 2 license

[anasatirbasa]

Hello @alextwoods,

Thank you very much for your feedback, we have addressed the comments from the pull request.

After further analysis, we changed from the original proposal of separate annotations to a unified @DynamoDbFlatten approach that handles both objects and maps. We chose this design for better API consistency. You can find the updated Solution Proposal here.

Could you please review this approach and provide your feedback?
Thank you very much!

[alextwoods]

It looks like checkstyle is failing - make sure you run checkstyle locally.

[anasatirbasa]

Hello @alextwoods,

Thank you very much for the review! I have addressed the comments raised and resolved the checkstyle issues.
Could you please take another look when you have a chance? Thank you!

[sonarqubecloud]

Quality Gate failed

Failed conditions
2 Security Hotspots
6.8% Duplication on New Code (required ≤ 3%)
C Reliability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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