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EclipseLink/Development/JPA 2.0/new collection mappings
< EclipseLink | Development | JPA 2.0
Contents
Element Collections
Summary
JPA 2.0 introduces support for collections of Embeddables and primitives through the @ElementCollection annotation. Support for ElementCollection of primitives will be easily supported through our BasicCollection and BasicMap support and will only require annotation processing updates. Support for lists of Embeddables should be supportable through the AggregateCollectionMapping. Support for Maps of Embeddables will be more difficult and will require completion of the Map Collections support feature.
@OrderBy must also be supported on these collection types.
See section 2.1.5, 9.1.2, 9.1.4, 9.1.7, 9.1.11 and 9.1.35 for details.
Examples
@ElementCollection @Column(name="DESIGNATION") // CollectionTable will default in this case, Entity name + "_" + attribute name // JoinColumns will default in this case which are different from BasicCollection collection table default private Collection<String> designations;
@ElementCollection @MapKeyColumn(name="Q_DATE") @Column(name="QUOTE") @CollectionTable(name="EXPERT_QUOTES", joinColumns=@JoinColumn(name="EBC_ID")) public Map<Date, String> getQuotes() { return quotes; }
// An element collection representing an aggregate collection mapping. @ElementCollection // CollectionTable will default // Column is not applicable here. // JoinColumns will default. // Both expert and novice consumers will define attribute overrides and // association overrides to apply to their respective tables. private Collection<Record> records; ... @Embeddable public class Record {
Functional Requirements
Design
Documentation
Testing
Work Required
- Develop model for testing
- approx 2 days
- Update Annotation Processing
- approx 2 days - processing @ElementCollection annotation / and XML for primitive
- approx 5 days - processing @ElementCollection annotation / and XML for Embeddables
- approx 5 days - integrating Map collections support for Embeddables
Open Issues
- How does the new JPA @CollectionTable relate to the existing EclipseLink @CollectionTable and what does it mean for users upgrading from one to the other.