assertNotNull("null operation return value", listAllMessagesMV);
log.debug("result: " + listAllMessagesMV);
MetaType resultType = listAllMessagesMV.getMetaType();
log.debug("resultType: "+resultType);
assertTrue("resultType instanceof CompositeMetaType", resultType instanceof CollectionMetaType);
CollectionMetaType resultCMT = (CollectionMetaType) resultType;
MetaType resultElementType = resultCMT.getElementType();
log.debug("resultElementType: "+resultElementType);
assertTrue("resultElementType instanceof CompositeMetaType", resultElementType instanceof CompositeMetaType);
log.debug("resultElementType: "+resultElementType);
CollectionValue listAllMessagesCV = (CollectionValue) listAllMessagesMV;
MetaValue[] listAllMessagesElements = listAllMessagesCV.getElements();