WW-2775 refactor class instantiation decision to a protected method

Thanks to Richard Wallace for patch

git-svn-id: https://svn.apache.org/repos/asf/struts/struts2/trunk@743781 13f79535-47bb-0310-9956-ffa450edef68

plugins/convention/src/main/java/org/apache/struts2/convention/PackageBasedActionConfigBuilder.java

@@ -413,9 +413,8 @@ public class PackageBasedActionConfigBuilder implements ActionConfigBuilder {
         Map<String, PackageConfig.Builder> packageConfigs = new HashMap<String, PackageConfig.Builder>();
 
         for (Class<?> actionClass : classes) {
-            // Skip all interfaces, enums, annotations, and abstract classes
-            if (actionClass.isAnnotation() || actionClass.isInterface() || actionClass.isEnum() ||
-                    (actionClass.getModifiers() & Modifier.ABSTRACT) != 0) {
+            // Skip classes that can't be instantiated
+            if (cannotInstantiate(actionClass)) {
                 continue;
             }
 
@@ -507,6 +506,14 @@ public class PackageBasedActionConfigBuilder implements ActionConfigBuilder {
         }
     }
 
+    /**
+     * Interfaces, enums, annotations, and abstract classes cannot be instantiated.
+     */
+    protected boolean cannotInstantiate(Class<?> actionClass) {
+        return actionClass.isAnnotation() || actionClass.isInterface() || actionClass.isEnum() ||
+                (actionClass.getModifiers() & Modifier.ABSTRACT) != 0;
+    }
+
     /**
      * Determines the namespace(s) for the action based on the action class. If there is a {@link Namespace}
      * annotation on the class (including parent classes) or on the package that the class is in, than