28.6 Managing State for Transient View Objects

Each view object can be declaratively configured to be passivation-enabled or not by using the Passivate State checkbox on the Tuning page of the View Object Editor. If a view object is not passivation enabled, then no information about it gets written in the application module passivation snapshot.

For passivation/activation purposes, both transient and SQL-calculated view object attributes are treated in the same way.

Transient view object attributes are not passivated by default. Due to their nature, they are usually intended to be "read only" and are very easily recreateable. So, it often doesn't make sense to passivate their values as part of the XML snapshot. However, by checking the Passivate checkbox on the Attribute page of the View Object Editor for any transient attribute, you can declaratively configure it to be passivation-enabled.

By default, all view objects are marked as passivation-enabled, and all transient attributes are not. That means that a transient view object — one that contains only transient attributes — is marked to be passivation enabled, but only passivates its information related to the current row and other non-transactional state.

It is worth noting that passivating transient view object attributes is more costly resource-wise and performance- wise, because transactional functionality is usually managed on the entity object level. Since transient view objects are not based on an entity object, this means that all updates are managed in the view object row cache and not in entity cache. Therefore, passivating transient view objects or transient view object attributes requires special runtime handling.

Usually passivation only saves the values that have been changed, but with transient view objects passivation has to save entire row. The row will only include the view object attributes marked for passivation).