WW-3498 Inject values into top of stack (model or action) instead of always using action. This does not break backward compatibility because nobody could use a model before this patch.

git-svn-id: https://svn.apache.org/repos/asf/struts/struts2/trunk@1065743 13f79535-47bb-0310-9956-ffa450edef68

plugins/json/src/main/java/org/apache/struts2/json/JSONInterceptor.java

@@ -83,7 +83,7 @@ public class JSONInterceptor extends AbstractInterceptor {
                 contentType = contentType.substring(0, iSemicolonIdx);
         }
 
-        Object rootObject;
+        Object rootObject = null;
         if (this.root != null) {
             ValueStack stack = invocation.getStack();
             rootObject = stack.findValue(this.root);
@@ -91,8 +91,6 @@ public class JSONInterceptor extends AbstractInterceptor {
             if (rootObject == null) {
                 throw new RuntimeException("Invalid root expression: '" + this.root + "'.");
             }
-        } else {
-            rootObject = invocation.getAction();
         }
 
         if ((contentType != null) && contentType.equalsIgnoreCase("application/json")) {
@@ -106,6 +104,9 @@ public class JSONInterceptor extends AbstractInterceptor {
                 if (dataCleaner != null)
                     dataCleaner.clean("", json);
 
+                if (rootObject == null) // model overrides action
+                    rootObject = invocation.getStack().peek();
+
                 // populate fields
                 populator.populateObject(rootObject, json);
             } else {
@@ -121,6 +122,9 @@ public class JSONInterceptor extends AbstractInterceptor {
                 if (obj instanceof Map) {
                     Map smd = (Map) obj;
 
+                    if (rootObject == null) // model makes no sense when using RPC
+                        rootObject = invocation.getAction();
+
                     // invoke method
                     try {
                         result = this.invoke(rootObject, smd);

plugins/json/src/test/java/org/apache/struts2/json/JSONInterceptorTest.java

@@ -322,6 +322,7 @@ public class JSONInterceptorTest extends StrutsTestCase {
         TestAction action = new TestAction();
 
         this.invocation.setAction(action);
+        this.invocation.getStack().push(action);
 
         interceptor.intercept(this.invocation);