What is Data Mapping

A mapper can be used to map the result of a source to an OpenNMS Requisition model. The mapper receives the result of the source. The source is not limited in the data model it provides to the mapper. The mapper has to provide an OpenNMS Requisition as its result. If the source provides a custom data model, the mapper has to map it into a Requisition. Some sources provide OpenNMS Requisition directly in a ready-to-use form; in those cases the echo.mapper can be used. Complex sources like the OCS-Sources provide OCS specific models and require their own specific mappers.

A mapper is configured in the requisition.properties for the requisition.

└── requisitions
    └── myRequisitionConfiguration
        └── requisition.properties

No-operation echo mapper

The echo mapper is a mapper that forwards the result of the source verbatim. That requires the source to provide a ready-to-use requisition and not a custom model. This mapper does not change the result of the source.

Empty requisition mapper

The null mapper is a special mapper that just provides an empty requisition. This can be useful to handle the entire mapping between the result of the source and the OpenNMS requisition in a script step.