Dali Project/specs/3.0/2.0ElementCollection

Functional Specification: Dali Support for JPA 2.0 Element Collection mapping

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bug 258490 - element collection support

Document History

Date	Author	Version Description & Notes
12-9-2009	Karen Butzke	Draft

Project overview

This feature covers the element collection mapping in the JPA 2.0 spec as well as any EclipseLink extensions.

Goals:

• Add Generic 2.0 support for Element Collection
• Add EclipseLink 3.0 support for Element Collection with relevant extensions
• Provide the appropriate defaults and validation for these settings

Concepts

Present any concepts relevant to the feature.

EclipseLink Element Collection Functional Spec

Requirements / Functionality

Caching

• @Cache supported in Entity and MappedSuperclass classes.
• Cache Type options
  • Default (Weak with Soft subcache)
  • Weak with Soft Subcache -> CacheType.SOFT_WEAK
  • Weak with Hard Subcache -> CacheType.HARD_WEAK
  • Weak -> CacheType.WEAK
  • Soft -> CacheType.SOFT
  • Full -> CacheType.FULL
  • Cache -> CacheType.CACHE - do we want to support this?? We didn't in the mapping workbench
  • None -> CacheType.NONE
• Coordination Type
  • Default (Send Object Changes)
  • Send Object Changes
  • Invalidate Changed Objects
  • Send New Objects with Changes
  • None
• @ExistenceChecking supported in Entity and MappedSuperclass classes.
  • Default (Check Database) - if the empty annotation is added, the default becomes Check Cache. See the second screen shot below
  • Check Cache -> ExistenceType.CHECK_CACHE
  • Check Cache then Database -> ExistenceType.CHECK_DATABASE
  • Assume Existence -> ExistenceType.ASSUME_EXISTENCE
  • Assume Non-Existence -> ExistenceType.ASSUME_NON_EXISTENCE
• Shared Cache
  • What should we label this instead? Possible options are 'Cache in L2 Cache' or 'Maintain in L2 Cache'. In the @Cache annotation it is just 'shared'.
  • If set to false then the panel is disabled and all Cache settings are removed. You will be left with @Cache(shared=false) in the java source.
• Expiry
  • Should we follow the Mapping Workbench or more closely follow the new EclipseLink annotations? The 'Time To Live Expiry' would add the expiry element to the Cache annotation. The 'Daily Expiry' would add the expiryTimeOfDay element to the Cache annotation. Potentially the radio buttons could be 'No Expiry', 'Expiry', 'Time of Day Expiry'

Entity 'Caching' section

Existence Checking combo if the ExistenceChecking annotation or xml element exists, the default changes.

For reference, 'Caching' tab from the MW

For reference, 'Refreshing Cache Options' section from the MW

Optimistic Locking

• @OptimisticLocking annotation supported in Entity and MappedSuperclass classes. Corresponding eclipselink-orm.xml element is optimistic-locking
• Type Options
  • Default (Version Column)
  • All Columns -> OptimisticLockingType.ALL_COLUMNS
  • Changed Columns -> OptimisticLockingType.CHANGED_COLUMNS
  • Selected Columns -> OptimisticLockingType.SELECTED_COLUMNS
  • Version Column -> OptimisticLockingType.VERSION_COLUMN
• Validation
  • Type is 'Selected Columns' but no columns are selected
  • Selected Columns must be mapped and must not be primary keys
  • If using Optimistic Locking with anything other than Version Column, the @Version annotation will be ignored (warning, not error, for this)
  • If 'cascade' is set and type is not 'Version Column', warning that it is not supported.
  • If type is 'Version Column' or @OptimisticLocking is specified without a type, there must be a mapping marked @Version.

• If no @Version annotation exists the Default option will display 'Default (None)
• If a Version annotation exists, the default option will display 'Default (Version Column)

For Reference, Locking tab from MW

Issues

This section lists the open issues that are still pending that must be decided prior to fully implementing this project's requirements.

Issue #	Owner	Description / Notes	Decision

Future Considerations

During the research for this project the following items were identified as out of scope but are captured here as potential future enhancements. If agreed upon during the review process these should be logged in the bug system.