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  1. JDO
  2. JDO-683

Allow version field/property to be visible to application

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      Description

      Currently, it requires a vendor extension to make the version attribute (field or property) of a PC visible to the application. Some knowledgeable applications may need not only read access to the version field, but also write access to it.

      I propose that we allow version metadata to specify that a version attribute be application-visible. For annotation-based metadata, I recommend that it be allowed to be placed on fields & methods. For XML metadata, add XML attributes "attribute-name" to the "version" element that allows the user to specify which field or property is to hold the application-visible version value.

      Along with this change would be verbiage in the spec noting that applications really shouldn't change this value, but a knowledgeable application may change it, based on a new PMF & PM property called something like "javax.jdo.option.OnVersionChangeByApplication" with the following specified values.

      THROW: (default) the implementation will throw JDOUserVersionChangeException (extends JDOUserException) as early as the time the value is set, at the next flush, or at commit.
      IGNORE: the implementation ignores the value the user set for the object's version
      ALLOW: the implementation allows and uses the value the user set for the object's version

      This allows users to who know how their implementation behaves on user-modified version values to take advantage of such behavior.

      All names proposed are up for discussion.

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            • Assignee:
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              Reporter:
              matthewadams Matthew T. Adams
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