Fix FindBugs error in DelayedListenerRegistration#getInstance 54/55054/1
authorTom Pantelis <tompantelis@gmail.com>
Fri, 14 Apr 2017 13:50:24 +0000 (09:50 -0400)
committerTom Pantelis <tompantelis@gmail.com>
Fri, 14 Apr 2017 13:50:24 +0000 (09:50 -0400)
The ObjectRegistration interface was recently changed to annotate
getInstance with @Nonnull to promise it will not return a null.
However DelayedListenerRegistration could return null if the delegate
is not set yet. In reality, we do not and should not ever call this
method on DelayedListenerRegistration instances so I changed it to
throw UnsupportedOperationException to make it explicit and to avoid
the FindBugs error.

Change-Id: I9fe374b23336d8ade65b2f1b697d93f50a090df9
Signed-off-by: Tom Pantelis <tompantelis@gmail.com>
opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DelayedListenerRegistration.java

index ac13272..8d73bc6 100644 (file)
@@ -39,8 +39,13 @@ abstract class DelayedListenerRegistration<L extends EventListener, M> implement
 
     @Override
     public L getInstance() {
-        final ListenerRegistration<L> d = delegate;
-        return d == null ? null : (L)d.getInstance();
+        // ObjectRegistration annotates this method as @Nonnull but we could return null if the delegate is not set yet.
+        // In reality, we do not and should not ever call this method on DelayedListenerRegistration instances anyway
+        // but, since we have to provide an implementation to satisfy the interface, we throw
+        // UnsupportedOperationException to honor the API contract of not returning null and to avoid a FindBugs error
+        // for possibly returning null.
+        throw new UnsupportedOperationException(
+                "getInstance should not be called on this instance since it could be null");
     }
 
     @Override

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