Notice: This Wiki is now read only and edits are no longer possible. Please see: https://gitlab.eclipse.org/eclipsefdn/helpdesk/-/wikis/Wiki-shutdown-plan for the plan.
Difference between revisions of "EclipseLink/Development/DBWS/oNmMetadata"
< EclipseLink | Development | DBWS
(→New 'oNm' Metadata) |
(→New 'oNm' Metadata) |
||
| Line 8: | Line 8: | ||
High-level Requirements: | High-level Requirements: | ||
| − | * the 'oNm.xml' metadata must support the majority of EclipseLink features (1:1, 1:M, M:N, queries | + | * the 'oNm.xml' metadata must support the majority of EclipseLink features (1:1, 1:M, M:N, queries) |
| + | ** NB: currently, new metadata formats do not support all EclipseLink features, not even all features required by DBWS (e.g. [https://bugs.eclipse.org/bugs/show_bug.cgi?id=211299 211299], [https://bugs.eclipse.org/bugs/show_bug.cgi?id=221876 221876]) | ||
* as there are no persistent model classes on the classpath, processing the metadata must use only simple scalar objects (Strings, booleans, numbers, etc.) for all capabilities and settings. | * as there are no persistent model classes on the classpath, processing the metadata must use only simple scalar objects (Strings, booleans, numbers, etc.) for all capabilities and settings. | ||
* an in-memory model of the metadata can be read in from an 'oNm.xml' file (or stream, URL, etc.) without persistent model classes on the classpath. | * an in-memory model of the metadata can be read in from an 'oNm.xml' file (or stream, URL, etc.) without persistent model classes on the classpath. | ||
Revision as of 10:35, 3 June 2009
Future DBWS work
At some point in the future, DBWS will switch from using 'native' EclipseLink metadata (a.k.a. Project deployment xml) to using 'oxm' and 'orm' (a.k.a JPA-style) metadata formats. In addition to using the new metadata formats, DBWS typically operates without persistent model classes; thus at runtime, a dynamic solution is required for the generation of persistent model classes.
New 'oNm' Metadata
High-level Requirements:
- the 'oNm.xml' metadata must support the majority of EclipseLink features (1:1, 1:M, M:N, queries)
- as there are no persistent model classes on the classpath, processing the metadata must use only simple scalar objects (Strings, booleans, numbers, etc.) for all capabilities and settings.
- an in-memory model of the metadata can be read in from an 'oNm.xml' file (or stream, URL, etc.) without persistent model classes on the classpath.
- an in-memory model of the metadata can be serialized to a file (or stream, URL, etc.) without persistent model classes on the classpath.
Dynamic Persistent Model Classes
High-level Requirements :
- an in-memory model of the 'oNm' metadata can be realized into runtime artifacts, including generating persistent model classes.
- generated persistent model classes must work when mapped simultaneously by both an orm and oxm metadata model.
i.e. a generated class must support the following: a row is retrieved from the database, built into an object and that very same object is serialized to XML (and vice-versa). - the existing multiple solutions for dynamic generation of persistent model classes (
o.e.p.sdo.helper.DynamicClassWriterando.e.p.internal.dynamicpersist.BaseEntityClassLoader) are re-factored to a single common solution.