Resolve "Allow collection and circular attributes as endpoint targets"

Closes #53 (closed)

• Check, if collection and circular attributes can be specified as send endpoint targets.
• Add test cases to ensure correct handling.
• Update documentation, that they can be used.

ragconnect.base/src/main/jastadd/Intermediate.jadd

@@ -521,14 +521,14 @@ aspect MustacheSendDefinition {
     java.util.List<SendIncrementalObserverEntry> result = new java.util.ArrayList<>();
     // "{{getterMethodName}}{{#IndexBasedListAccess}}_int{{/IndexBasedListAccess}}"
     result.add(SendIncrementalObserverEntry.of(getterMethodName() + (getIndexBasedListAccess() ? "_int" : ""),
-            getIndexBasedListAccess(), "index"));
+            getIndexBasedListAccess(), getIndexBasedListAccess() ? "index" : "null"));
     if (indexBasedAccessAndTargetIsNTA()) {
       // "{{getterMethodName}}List"
       result.add(SendIncrementalObserverEntry.of(getterMethodName() + "List", false, "index"));
     }
     if (targetIsAttribute()) {
       // "{{parentTypeName}}_{{getterMethodName}}{{#IndexBasedListAccess}}_int{{/IndexBasedListAccess}}"
-      result.add(SendIncrementalObserverEntry.of(parentTypeName() + "_" + getterMethodName() + (getIndexBasedListAccess() ? "_int" : ""), getIndexBasedListAccess(), "index"));
+      result.add(SendIncrementalObserverEntry.of(parentTypeName() + "_" + getterMethodName() + (getIndexBasedListAccess() ? "_int" : ""), getIndexBasedListAccess(), getIndexBasedListAccess() ? "index" : "null"));
     }
     return result;
   }
@@ -611,10 +611,10 @@ containingEndpointDefinition().getIndexBasedListAccess());
   syn String EndpointDefinition.typeName() = type().getName();
   syn String MEndpointDefinition.typeName() = getEndpointDefinition().typeName();
 
-  static SendIncrementalObserverEntry SendIncrementalObserverEntry.of(String attributeString, boolean useParams, Object params) {
+  static SendIncrementalObserverEntry SendIncrementalObserverEntry.of(String attributeString, boolean compareParams, Object params) {
     return new SendIncrementalObserverEntry()
-            .setParams(useParams ? params : null)
-            .setCompareParams(useParams)
+            .setParams(params)
+            .setCompareParams(compareParams)
             .setAttributeString(attributeString);
   }
 }