Mapping Independent and Dependent
Nodes
Independent context nodes can always be mapped. They can be mapped to any nodes in other non-view contexts, as long as this does not result in a closed mapping cycle, where no original node exists.
The child nodes of mapped nodes do not have to be mapped. In this case, their content is determined using the mechanism of supply functions. If they are mapped, then they are mapped to child nodes of the node to which their parent node is mapped.
Conversely, child nodes of non-mapped parent nodes cannot be mapped, otherwise this would result in irresolvable conflicts at runtime with respect to the parent-child relation in the context and the mapping relation.
An important rule has to be observed when you define mapped parent and child nodes:
For the parent node, if only the node collection is mapped but not the node selection, then the original child node has to be of type non-singleton.
The reason for this is shown in the following overview:
Scenario 1: (MP to OP: mappingType = collection_only )
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Node MP maps its node collection to OP only, but not its node selection. (1). The child node OC must be of type non-singleton so that MC can be mapped to OC. (2). The lead selections of the parent node are different in the figure above. If the OC node in this case was of type singleton, then at runtime it would contain such node elements that fit the parent element selected in OP but not the other element that is selected in MP. MC would have to reference node elements that are not loaded in OC. |
Scenario 1: (MP to OP: mappingType = collection_and_selection)
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Node MP is mapped to node OP and also points to the same node selection as OP (1). Regardless of whether OC is a singleton node, MC can be mapped to OC. OC always contains the suitable node collection (2, 3). If OC were of type non-singleton, this would mean that separate child node instances would exist at runtime even for the sibling node elements of the selected parent node element. These are not required, however, to display the mapped node element in MC. |
