provides read/write access to a configuration data layer.
A layer contains the configuration setting changes to be performed
on a default layer (or schema) to obtain the values of those settings
for a given entity and component.
An updatable layer can be read or replaced with another layer.
If the implementation supports
::com::sun::star::util::XTimeStamped,
then after executing XUpdatableLayer::replaceWith()
the timestamp will be the one for the replaced contents and
if reading after updates is supported the next read will reproduce the
replaced data.
provides write access to the contents of the layer.
Depending of the actual type (simple, i.e pure XLayer or
composite, i.e XCompositeLayer) of the current layer and
the provided replacement layer, the operation performed
by XUpdatableLayer::replaceWith(), will vary.
For the different current/replacement layer combinations, we have:
Simple/Simple
the provided layer's contents replace the current one's.
Composite/Composite
all layers (main and sub) present in the
provided layer are used to replace the corresponding current
layer contents. Sublayers present in the current layer but
not in the provided one are left untouched. Sublayers present
in the provided layer but not in the current one are added to
the current layer.
Simple/Composite
the main layer and sublayers of the provided layer
are merged into one whose contents replace the current layer.
Composite/Simple
the provided layer is split into a composite one whose contents
are then used to replace the current layer as described above.
Not all implementations of XUpdatableLayer
support conversions of the replacement layer.
In such a case the sublayers of the provided layer may be ignored
or all simple data be merged into the main layer.
