spring-projects / spring-projects/spring-data-rest

Support for @ElementCollection deserialization (1.0.0 Branch)

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status: waiting-for-triage
Dominant language
Java
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Description

When using JPA The RepositoryAwareJacksonModule doesn't seem to deserialize an @ElementCollection of type Map correctly.

ie an entity with:

...
@ElementCollection
private Map<Long, String> userIdSessionKeys;
...

which is attempted to be created with:

... , 'userIdSessionKeys': { 123: 'aslkdfjalkj=43Z' }, ...

Will case an error at line 329 of the RepositoryAwareJacksonModule, either assigning the key of the map element as a property or as a hateos reference.

Ideally when the attrMeta.attribute.persistentAttributeType is ELEMENT_COLLECTION is detected (I have no idea what the equivalent is in other spring-data modules) the default jackson deserializer type parser is used.

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading RepositoryAwareJacksonModule around line 329 and trace how Map entries in an @ElementCollection are interpreted during deserialization. Compare that path with the default Jackson type parsing and check how other Spring Data modules handle equivalent metadata. Done means a Map<Long, String> element collection can be created from the shown JSON without treating its key as a property or HAL reference.

Written by the indexing model from the issue text.

Assessment

Tech stack
java, spring
Domain
api, backend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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