Prefer primary Json(De)Serializer.None over secondary null in AnnotationIntrospectorPair.find(De)Serializer

[TuomasKiviaho]

Now that the #1581 took care of the twisted behavior of _isExplicitClassOrOb, I feel confident in what I'm doing :-)

I'm evaluating a JaxbAnnotationIntrospector change below that might cause side effects and be a bad idea after all but...

     @Override
-    public JsonSerializer<?> findSerializer(Annotated am)
+    public Object findSerializer(Annotated am)
     {
 ...
-        return null;
+        return JsonSerializer.None.class;
     }

... nevertheless I found out that the Json(De)Serializer.None is a nifty class that can't currently be utilized with AnnotationIntrospectorPair when the secondary introspector usually just returns null. This patch below changes this behaviour so that the primary implicit/missing/bogus is preferred over the secondary one.

     @Override
     public Object findSerializer(Annotated am) {
         Object r = _primary.findSerializer(am);
-        return _isExplicitClassOrOb(r, JsonSerializer.None.class)
-                ? r : _secondary.findSerializer(am);
+        if (!_isExplicitClassOrOb(r, JsonSerializer.None.class)) {
+            Object r2 = _secondary.findSerializer(am);
+            if (_isExplicitClassOrOb(r2, JsonSerializer.None.class)) {
+                r = r2;
+            }
+        }
+        return r;
     }
     
     @Override
     public Object findKeySerializer(Annotated a) {
         Object r = _primary.findKeySerializer(a);
-        return _isExplicitClassOrOb(r, JsonSerializer.None.class)
-                ? r : _secondary.findKeySerializer(a);
+        if (!_isExplicitClassOrOb(r, JsonSerializer.None.class)) {
+            Object r2 = _secondary.findKeySerializer(a);
+            if (_isExplicitClassOrOb(r2, JsonSerializer.None.class)) {
+                r = r2;
+            }
+        }
+        return r;
     }
 
     @Override
     public Object findContentSerializer(Annotated a) {
         Object r = _primary.findContentSerializer(a);
-        return _isExplicitClassOrOb(r, JsonSerializer.None.class)
-                ? r : _secondary.findContentSerializer(a);
+        if (!_isExplicitClassOrOb(r, JsonSerializer.None.class)) {
+            Object r2 = _secondary.findContentSerializer(a);
+            if (_isExplicitClassOrOb(r2, JsonSerializer.None.class)) {
+                r = r2;
+            }
+        }
+        return r;
     }
     
     @Override
     public Object findNullSerializer(Annotated a) {
         Object r = _primary.findNullSerializer(a);
-        return _isExplicitClassOrOb(r, JsonSerializer.None.class)
-                ? r : _secondary.findNullSerializer(a);
+        if (!_isExplicitClassOrOb(r, JsonSerializer.None.class)) {
+            Object r2 = _secondary.findNullSerializer(a);
+            if (_isExplicitClassOrOb(r2, JsonSerializer.None.class)) {
+                r = r2;
+            }
+        }
+        return r;
     }
     
     @Deprecated
@@ -626,22 +646,37 @@ public class AnnotationIntrospectorPair
     @Override
     public Object findDeserializer(Annotated am) {
         Object r = _primary.findDeserializer(am);
-        return _isExplicitClassOrOb(r, JsonDeserializer.None.class)
-                ? r : _secondary.findDeserializer(am);
+        if (!_isExplicitClassOrOb(r, JsonDeserializer.None.class)) {
+            Object r2 = _secondary.findDeserializer(am);
+            if (_isExplicitClassOrOb(r2, JsonDeserializer.None.class)) {
+                r = r2;
+            }
+        }
+        return r;
     }
 
     @Override
     public Object findKeyDeserializer(Annotated am) {
         Object r = _primary.findKeyDeserializer(am);
-        return _isExplicitClassOrOb(r, KeyDeserializer.None.class)
-                ? r : _secondary.findKeyDeserializer(am);
+        if (!_isExplicitClassOrOb(r, JsonDeserializer.None.class)) {
+            Object r2 = _secondary.findKeyDeserializer(am);
+            if (_isExplicitClassOrOb(r2, JsonDeserializer.None.class)) {
+                r = r2;
+            }
+        }
+        return r;
     }
 
     @Override
     public Object findContentDeserializer(Annotated am) {
         Object r = _primary.findContentDeserializer(am);
-        return _isExplicitClassOrOb(r, JsonDeserializer.None.class)
-                ? r : _secondary.findContentDeserializer(am);
+        if (!_isExplicitClassOrOb(r, JsonDeserializer.None.class)) {
+            Object r2 = _secondary.findContentDeserializer(am);
+            if (_isExplicitClassOrOb(r2, JsonDeserializer.None.class)) {
+                r = r2;
+            }
+        }
+        return r;
     }
 
     @Override

[cowtowncoder]

Ah yes, but of course you are right: check must be applied for all return values, not just first masking one. I'll go and improve test, fix this too.