Add yang-data-api API evolution guidance

This adds 3.0.0 and 4.0.0 evaluation FIXMEs. These need to be accounted
for in release planning and adopted, rejected or pushed out.

Change-Id: I50657a6bbb020189a4ac8662afb16bf1f7b7215f
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

diff --git a/yang/yang-data-api/src/main/java/org/opendaylight/yangtools/yang/data/api/YangInstanceIdentifier.java b/yang/yang-data-api/src/main/java/org/opendaylight/yangtools/yang/data/api/YangInstanceIdentifier.java
index 6f2c49cfa3d28a8d8d8f54c10c0e3a56fdfaf135..af66cd48d46b9dc9b828baa2f78136987b7d2b6d 100644 (file)
--- a/yang/yang-data-api/src/main/java/org/opendaylight/yangtools/yang/data/api/YangInstanceIdentifier.java
+++ b/yang/yang-data-api/src/main/java/org/opendaylight/yangtools/yang/data/api/YangInstanceIdentifier.java
@@ -76,6 +76,9 @@ import org.opendaylight.yangtools.yang.data.api.schema.LeafSetEntryNode;
  *
  * @see <a href="http://tools.ietf.org/html/rfc6020#section-9.13">RFC6020</a>
  */
+// FIXME: 3.0.0: this concept needs to be moved to yang-common, as parser components need the ability to refer
+//               to data nodes -- most notably XPath expressions and {@code default} statement arguments need to be able
+//               to represent these.
 public abstract class YangInstanceIdentifier implements Path<YangInstanceIdentifier>, Immutable, Serializable {
     /**
      * An empty {@link YangInstanceIdentifier}. It corresponds to the path of the conceptual

diff --git a/yang/yang-data-api/src/main/java/org/opendaylight/yangtools/yang/data/api/schema/NormalizedNode.java b/yang/yang-data-api/src/main/java/org/opendaylight/yangtools/yang/data/api/schema/NormalizedNode.java
index 72688525ea028877f3539e592c99602bad7e7568..31a385ce4b5009d91810c09190d1f7da301ecf49 100644 (file)
--- a/yang/yang-data-api/src/main/java/org/opendaylight/yangtools/yang/data/api/schema/NormalizedNode.java
+++ b/yang/yang-data-api/src/main/java/org/opendaylight/yangtools/yang/data/api/schema/NormalizedNode.java
@@ -22,6 +22,28 @@ import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgum
  * @param <K> Local identifier of node
  * @param <V> Value of node
  */
+/*
+ * FIXME: 3.0.0: NormalizedNode represents the perfectly-compliant view of the data, as evaluated by an implementation,
+ *               which is currently singular, with respect of its interpretation of a SchemaContext. This includes
+ *               leaf values, which are required to hold normalized representation for a particular implementation,
+ *               which may be affected by its understanding of any YANG extensions present -- such as optional type
+ *               handling hints and bindings.
+ *
+ *               Implementations (i.e. the reference implementation and parsers) will need to start using
+ *               yang.common.Uint8 and friends and, if possible, express data validation in terms
+ *               of yang.common.CanonicalValue and yang.common.CanonicalValueValidator.
+ *
+ *               This notably means that to efficiently implement any sort of lenient parsing, we need a separate
+ *               concept which contains an unverified, potentially non-conformant data tree, which the consumer needs
+ *               to check/fixup if it wishes to use it as a NormalizedNode. Such a concept should be called
+ *               "UnverifiedData".
+ */
+/*
+ * FIXME: 4.0.0: Once we have UnverifiedData, we should really rename this to "NormalizedData" or similar to unload
+ *               some "Node" ambiguity. "Node" should be a generic term reserved for a particular domain -- hence 'node'
+ *               can be used to refer to either a 'schema node' in context of yang.model.api, or to
+ *               a 'normalized data node' in context of yang.data.api.
+ */
 public interface NormalizedNode<K extends PathArgument, V> extends Identifiable<K> {
     /**
      * QName of the node as defined in YANG schema.