BUG-650: fromYangInstanceIdentifier() can return null

Properly interpret a null return as an absent identifier.

Clarified cast in #toBinding(Entry) and explained
why it is necessary, even if Eclipse reports
it as unnecessary (difference in various java compilers).

Change-Id: I2dd7cd631cb958a28ddce8db62d20e0292ae8a39
Signed-off-by: Robert Varga <rovarga@cisco.com>

diff --git a/opendaylight/md-sal/sal-binding-broker/src/main/java/org/opendaylight/controller/md/sal/binding/impl/BindingToNormalizedNodeCodec.java b/opendaylight/md-sal/sal-binding-broker/src/main/java/org/opendaylight/controller/md/sal/binding/impl/BindingToNormalizedNodeCodec.java
index bbb269cf59297e34983597cdc0f83426f3ceadc9..d7314e5362873b0db2e3fa6a2a20b93f527725d2 100644 (file)
--- a/opendaylight/md-sal/sal-binding-broker/src/main/java/org/opendaylight/controller/md/sal/binding/impl/BindingToNormalizedNodeCodec.java
+++ b/opendaylight/md-sal/sal-binding-broker/src/main/java/org/opendaylight/controller/md/sal/binding/impl/BindingToNormalizedNodeCodec.java
@@ -13,6 +13,8 @@ import com.google.common.base.Optional;
 import java.util.Iterator;
 import java.util.Map.Entry;
 
+import javax.annotation.Nonnull;
+
 import org.opendaylight.controller.md.sal.common.impl.util.compat.DataNormalizationException;
 import org.opendaylight.controller.md.sal.common.impl.util.compat.DataNormalizationOperation;
 import org.opendaylight.controller.md.sal.common.impl.util.compat.DataNormalizer;
@@ -72,7 +74,7 @@ public class BindingToNormalizedNodeCodec implements SchemaContextListener,AutoC
     public Optional<InstanceIdentifier<? extends DataObject>> toBinding(final YangInstanceIdentifier normalized)
                     throws DeserializationException {
         try {
-            return Optional.<InstanceIdentifier<? extends DataObject>>of(codecRegistry.fromYangInstanceIdentifier(normalized));
+            return Optional.<InstanceIdentifier<? extends DataObject>>fromNullable(codecRegistry.fromYangInstanceIdentifier(normalized));
         } catch (IllegalArgumentException e) {
             return Optional.absent();
         }
@@ -82,14 +84,26 @@ public class BindingToNormalizedNodeCodec implements SchemaContextListener,AutoC
         return legacyToNormalized;
     }
 
-    @SuppressWarnings("unchecked")
     public Optional<Entry<InstanceIdentifier<? extends DataObject>, DataObject>> toBinding(
-            final Entry<YangInstanceIdentifier, ? extends NormalizedNode<?, ?>> normalized)
+            final @Nonnull Entry<YangInstanceIdentifier, ? extends NormalizedNode<?, ?>> normalized)
                     throws DeserializationException {
         try {
-            @SuppressWarnings("rawtypes")
-            Entry binding = codecRegistry.fromNormalizedNode(normalized.getKey(), normalized.getValue());
-            return Optional.<Entry<InstanceIdentifier<? extends DataObject>, DataObject>>fromNullable(binding);
+            /*
+             * This cast is required, due to generics behaviour in openjdk / oracle javac
+             *
+             * InstanceIdentifier has definition InstanceIdentifier<T extends DataObject>,
+             * this means '?' is always  <? extends DataObject>. Eclipse compiler
+             * is able to determine this relationship and treats
+             * Entry<InstanceIdentifier<?>,DataObject> and Entry<InstanceIdentifier<? extends DataObject,DataObject>
+             * as assignable. However openjdk / oracle javac treats this two types
+             * as incompatible and issues a compile error.
+             *
+             * It is safe to  loose generic information and cast it to other generic signature.
+             *
+             */
+            @SuppressWarnings({ "unchecked", "rawtypes" })
+            final Entry<InstanceIdentifier<? extends DataObject>, DataObject> binding = (Entry) codecRegistry.fromNormalizedNode(normalized.getKey(), normalized.getValue());
+            return Optional.fromNullable(binding);
         } catch (IllegalArgumentException e) {
             return Optional.absent();
         }
@@ -130,7 +144,7 @@ public class BindingToNormalizedNodeCodec implements SchemaContextListener,AutoC
     }
 
     @Override
-    public void close() throws Exception {
+    public void close() {
         // NOOP Intentionally
     }
 }