Granular overlays
Granular overlays allow you to modify only some aspects of an object and inherit other aspects from the origin object.
See the following video for an overview about granular overlays.
Note
The video is recorded using the earlier version of AR System and is valid for AR System 9.1 and later versions.
Use player to increase quality or switch to full screen | YouTube:
https://www.youtube.com/watch?v=LGxdaHrQhto
You can divide objects into subcomponents, or grains, that can have different overlay types applied to them. You can do the following:
- Add to some of the grains of an object from the origin object
- Overwrite other grains
- Inherit other grains
Reducing the number of elements that are overlaid means you will have fewer items to reconcile after applying a patch or an upgrade.
The overlay types that you can apply to the objects are:
- Additive—Allows you to specify information that is added to the information defined in the origin object. If the definition of the origin object changes (for example, during an upgrade), the additions you specify are appended to the overlay object in addition to whatever is in the new origin definition.
Overwrite—Allows you to copy and then modify the origin definition. The copied information with any changes is preserved if the definition of the origin object changes.
If an origin object is modified during a patch or upgrade, the overwrite type of overlays must be examined, and sometimes reconciled.- No Overlay—Uses the definition of the origin object. If that definition changes, the new definition is used.
No Overlay is still an overlay. The No Overlay overlay type is for an overlay that inherits everything.
An overlay with grains that are set to No Overlay is referred to as a transparent overlay which is an overlay that is always identical to its origin object. Transparent overlays are useful where an overlay must be created to allow creation of other overlays. For example, it is not possible to overlay a field unless the form on which the field resides is also overlaid. If the form is overlaid only so that its fields can be overlaid, a transparent overlay ensures that all changes to the origin form are visible in the overlay. This means that no reconciliation is needed for the form overlay if a patch or an upgrade modifies the origin form.
For a list of overlayable application components and the granularity at which they can be customized, see Overlayable and non-overlayable objects.
What happens to granular overlays when you upgrade or apply a patch
During an upgrade or when applying a patch, changes made to origin objects are also made to the inherited and extended portions of an overlay. After the upgrade or patch installation, you should manually reconcile any portions of an overlay that were overwritten and whose origin object is changed.
Best practice
What happens when you change an overlay type
After setting the type of overlay for a granular component, you can change the type. For example, if an overlay form has additional permissions (Additive overlay), you can later change the overlay type to overwrite the base permissions (Overwrite overlay) and use only the permissions that you specify. When you change the overlay type, you can revert these changes.
The following table explains the state transitions for the server when it transitions from any overlay mode to any other mode.
State transitions for the server—transitions from any overlay mode to any other mode
blank | To Additive | To Overwrite | To No Overlay |
|---|---|---|---|
From Additive | Remove current extended properties. Add new extended properties. No change to existing base properties. | Remove current extended and base properties. Add new overwrite properties. | Remove current extended properties. No change to existing base properties. |
From Overwrite | Remove current overwrite properties. Reload base properties and add new extended properties. | Remove current overwrite properties. Add new overwrite properties. | Remove current overwrite properties and reload base properties. |
From No Overlay | Add new extended properties. No change to existing base properties. | Remove base properties. Add new overwrite properties. | No change. |
The following table explains the state transitions for the server when there is no data in the corresponding attribute.
State transitions for the server—no data in the corresponding attribute
blank | To Additive | To Overwrite | To No Overlay |
|---|---|---|---|
From Additive | No change. | Remove extended properties. Make the current base properties overwrite properties. | Remove extended properties. No change to base properties. |
From Overwrite | Reload base properties. Add extra properties as extended properties. | No change. | Remove current overwrite properties. Reload base properties. |
From No Overlay | No change to base properties. | Make the current base properties overwrite properties. | No change. |
The following table explains the state transitions for
Developer Studio
.
State transitions for
Developer Studio
blank | To Additive | To Overwrite | To No Overlay |
|---|---|---|---|
From Additive | No change. | Revert to base properties. | Revert to base properties. |
From Overwrite | Remove current overwrite properties. Reload base properties. | No change. | Remove current overwrite properties. Reload base properties. |
From No Overlay | Add new extended properties. No change to existing base properties. | Add new extended properties. No change to existing base properties. | No change. |
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