This requires updating JAX-RS structure so that we also service the root element and return the combination of individual API resources.
+---- {+restconf}
+---- data
| ...
+---- operations?
| ...
+--ro yang-library-version string
i.e. we are servicing /data, /yang-library-version and /operations, but do not service /.
We need to find out some way how to return a combination of /data, /yang-library-version and /operations.
The problem of patchset 9 is that we are not able to read other data except of YANG library version.
There are at least these possibilities:
1. Rewrite RestconfImpl class to implement all needed services (RestconfDataService, RestconfOperationsService) via delegation.
It requires the constructor as following:
public RestconfImpl(final DatabindProvider databindProvider, final RestconfDataService dataService, final RestconfOperationsService operationsService) { this.databindProvider = requireNonNull(databindProvider); this.dataService = requireNonNull(dataService); this.operationsService = requireNonNull(operationsService); }
and additional changes in RestconfApplication and maybe also in restconf-bp.xml.
2. Refactor RestconfDataServiceImpl and RestconfOperationsServiceImpl logic into utility methods which allows us to read data and operations from RestconfImpl class.
3. Copy and paste code which we need...
Following solution will not work for similar reasons like in NETCONF-822. We cannot create full data like this:
final var libVersion = getLibraryVersion().getData(); final var data = ((NormalizedNodePayload) readData(uriInfo).getEntity()).getData(); final var result = Builders.containerBuilder() .withNodeIdentifier(NodeIdentifier.create(Restconf.QNAME)) .withChild((LeafNode) libVersion) .withChild((ContainerNode) data) .build();
because then we get a failure from writers:
Caused by: java.lang.IllegalArgumentException: Data tree child (urn:ietf:params:xml:ns:yang:ietf-restconf-monitoring?revision=2017-01-26)restconf-state not present in schema parent (urn:ietf:params:xml:ns:yang:ietf-restconf?revision=2017-01-26)restconf at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.notPresent(SchemaInferenceStack.java:1046) ~[?:?] at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.lambda$pushData$6(SchemaInferenceStack.java:853) ~[?:?] at java.util.Optional.orElseThrow(Optional.java:403) ~[?:?] at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.pushData(SchemaInferenceStack.java:853) ~[?:?] at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.pushData(SchemaInferenceStack.java:847) ~[?:?] at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.pushData(SchemaInferenceStack.java:841) ~[?:?] at org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.enterDataTree(SchemaInferenceStack.java:531) ~[?:?] at org.opendaylight.yangtools.yang.data.util.NormalizedNodeStreamWriterStack.enterDataTree(NormalizedNodeStreamWriterStack.java:204) ~[?:?] at org.opendaylight.yangtools.yang.data.util.NormalizedNodeStreamWriterStack.startContainerNode(NormalizedNodeStreamWriterStack.java:276) ~[?:?] at org.opendaylight.yangtools.yang.data.codec.gson.JSONNormalizedNodeStreamWriter.startContainerNode(JSONNormalizedNodeStreamWriter.java:406) ~[?:?] at org.opendaylight.restconf.nb.rfc8040.jersey.providers.ParameterAwareNormalizedNodeWriter.wasProcessedAsCompositeNode(ParameterAwareNormalizedNodeWriter.java:273) ~[?:?]
what's true because Restconf YANG model defines data as just empty container 
.
OK.. we can maybe try to adjust little bit - but I expect it will not work anyway..