Adding configuration option to Solution Pack Compound to have parent compound objects derive TN from it's first child.
Compound objects will derive their thumbnail(TN) datastream from the TN datastream of it's first child.
The following is true only when the configuration item "Use derivative hooks for parent thumbnail updates?" is checked.
Added two(2) derivative hooks to the compound solution pack:
#1 - islandora_compound_object_compound_cmodel_islandora_derivative
Catches changes on parent level. This is more of a double check feature to ensure that first-child and parent are in sync after a change.
#2 - islandora_compound_object_islandora_derivative
Checks for changes to the TN datastream of an object. Checks the object for:
a) is it part of a compound.
b) is this the first child of the compound.
If both the above conditions are met then proceed to change the parent's TN
The following actions will update the parent object's TN datastream:
- ingest a first child
- re-order children
- set a first child
- remove a first child (when a second child would then become first)
- change a first child's TN DS
It is worth noting that there are some checks that will happen on every object whose TN changes. I think the performance impact is minimal but non-zero.
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