private void schemaMapProcessing(Processing processing) {
        final List<DocumentOperation> documentOperations = processing.getDocumentOperations();
        for (int i = 0; i < documentOperations.size(); i++) {
            DocumentOperation op = documentOperations.get(i);
            if (op instanceof DocumentPut) {
                documentOperations.set(i, configDoc(processor, (DocumentPut) op));
            } else if (op instanceof DocumentUpdate) {
                documentOperations.set(i, configDocUpd(processor, (DocumentUpdate) op));
            }
        }
    }
The DocumentUpdate object a processor should work on. The one in args, or schema mapped.

@return a DocumentUpdate
docproc/src/main/java/com/yahoo/docproc/Call.java