Passivate Transient Attributes

Question

I have a transient attribute in a View Object that reflects the results of a costly calculation. Passivate to PS_TXN seems to me the best way to keep the result from one request to another.
1. Has the calculated value to be cached by setAttributeInternal in the view row internal buffer, or has it to be cached as a member of the view row impl ?
Passivation calls the getter, so it makes no difference. But how are members of view row objects cleared in the case they are "recycled" ?
2. It seems to me that activating a transient attribute is somewhat buggy: the getter is always called before the restored value appears in the mInner-mCalcs member of a view row, which calculates the value unnecessarily. If the value was not cached with setAttributeInternal, it never appears in mCals.

Answer 1

If your transient attributes are updateable, but you use them only within the scope of a single request (e.g. you set the value within a particular request and use it only until the end of this request but not later), then you do not have to passivate them. However, if they are updateable and you need their values to survive across multiple requests, then you must ensure that these attributes are passivated. In order to configure them to passivate you should do the following:
1. Check the checkbox "Passivate State (e.g. Current Row, Bind Variables, etc.)" in the section "General/Tunning" in VO's definition dialog box;
2. Either check the checkbox "Including All Transient Values" in the same section or leave it unchecked but check the checkbox "Passivate" in the definition of the corresponding VO attributes.
N.B. The setting "Include All Transient Values" affects not only the transient VO attributes but the SQL-derived VO attributes (that are not entity-based) too.
The configuration parameter "jbo.txn.disconnect_level" has nothing to do with passivation/activation. The correct way to test if your VOs behave correctly under passivation/activation is to disable AM pooling (e.g. to uncheck the checkbox "Enable Application Module Pooling" in the corresponding AM Configuration dialog box). When AM Pooling is disabled ADF passivates the corresponding AM state at the end of each HTTP request and activates it at the beginning of next request and so on. In this way you can check if your VOs are passivation/activation-safe.
Please, have a look at the article [url http://docs.oracle.com/cd/E23943_01/web.1111/b31974/bcstatemgmt.htm#sm0318]Application State Management in the documentation for more information and detailed explanation.
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