Has the interface <none> in the gdbus-monitor output a special meaning?
What API call is required to create such a message using GDbus (g_dbus_connection_register_object does not allow to pass NULL as GDBusInterfaceInfo * and that seems to be the only to register a object to a path)
related: dbus - register object to remote on interface NULL
Looking into dbus-monitor's source code shows that it occures as soon as DBUS_EXPORT const char * dbus_message_get_interface ( DBusMessage * message ) returns NULL (which is valid!, but not according to the spec which requires minimum one . and two name chunks!! EDIT: A noteable exception are method calls which do not require the interface field of a message to be set http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-types).
g_dbus_message_new_method_call (...) allows interface_ to be null. But that still only solves half the problems (sender). The receiver method seems to not exist for interface_s being NULL.
Turns out it is a bug, I did a source code investigation and filed a bug (including fix) https://bugzilla.gnome.org/show_bug.cgi?id=706675
client needs to know the interface name while subscribing g_dbus_connection_signal_subscribe to any signal else it will listen to all interfaces hence inefficient.
Interface is required to bind methods and signals in single entity mentioned in server introspection xml file.
Related
My problem will probably be explained better with code.
Consider the snippet below:
// First read
OntModel m1 = ModelFactory.createOntologyModel();
RDFDataMgr.read(m1,uri0);
m1.loadImports();
// Second read (from the same URI)
OntModel m2 = ModelFactory.createOntologyModel();
RDFDataMgr.read(m2,uri0);
m2.loadImports();
where uri0 points to a valid RDF file describing an ontology model with n imports.
and the following custom ReadHook (which has been set in advance):
#Override
public String beforeRead(Model model, String source, OntDocumentManager odm) {
System.out.println("BEFORE READ CALLED: " + source);
}
Global FileManager and OntDocumentManager are used with the following settings:
processImports = true;
caching = true;
If I run the snippet above, the model will be read from uri0 and beforeRead will be invoked exactly n times (once for each import).
However, in the second read, beforeRead won't be invoked even once.
How, and what should I reset in order for Jena to invoke beforeRead in the second read as well?
What I have tried so far:
At first I thought it was due to caching being on, but turning it off or clearing it between the first and second read didn't do anything.
I have also tried removing all ignoredImport records from m1. Nothing changed.
Finally got to solve this. The problem was in ModelFactory.createOntologyModel(). Ultimately, this gets translated to ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RDFS_INF,null).
All ontology models created with the static OntModelSpec.OWL_MEM_RDFS_INF will have their ImportsModelMaker and some of its other objects shared, which results in a shared state. Apparently, this state has blocked the reading hook to be invoked twice for the same imports.
This can be prevented by creating a custom, independent and non-static OntModelSpec instance and using it when creating an OntModel, for example:
new OntModelSpec( ModelFactory.createMemModelMaker(), new OntDocumentManager(), RDFSRuleReasonerFactory.theInstance(), ProfileRegistry.OWL_LANG );
My SAPui5 web app throws this error in Chrome's console:
The following problem occurred: HTTP request failed500,Internal Server Error,{"error":{
"code":"/IWBEP/CM_MGW_RT/053","message":{"lang":"en","value":"Default changeset impleme
ntation allows only one operation"},"innererror":{"application":{"component_id":"CA","s
ervice_namespace":"/SAP/","service_id":"YFLEXUI_LEAVE_REQUEST_SRV","service_version":"0
001"},"transactionid":"something","timestamp":"something","Error_Resolution":{"SAP_Tran
saction":"For backend administrators: run transaction /IWFND/ERROR_LOG on SAP Gateway h
ub system and search for entries with the timestamp above for more details","SAP_Note":
"See SAP Note 1797736 for error analysis (https://service.sap.com/sap/support/notes/179
7736)"},"errordetails":[{"code":"/IWBEP/CX_MGW_TECH_EXCEPTION","message":"Default chang
eset implementation allows only one operation","propertyref":"","severity":"error","tar
get":""}]}}} -
According to some posts on the internet, the problem is caused by the conflict between these methods:
/iwbep/if_mgw_appl_srv_runtime~changeset_begin
/iwbep/if_mgw_appl_srv_runtime~changeset_end
and
/iwbep/if_mgw_core_srv_runtime~changeset_begin
/iwbep/if_mgw_core_srv_runtime~changeset_end
Most people advice to redefine the methods /iwbep/if_mgw_appl_srv_runtime~changeset_begin and /iwbep/if_mgw_appl_srv_runtime~changeset_end.
This is my /iwbep/if_mgw_appl_srv_runtime~changeset_begin method:
METHOD /iwbep/if_mgw_appl_srv_runtime~changeset_begin.
* Default Implementation:
* - Local Update Task
* - Only one operation in each changeset
* - No deferred processing: Immediate process changset operation
SET UPDATE TASK LOCAL.
IF lines( it_operation_info ) > 1.
RAISE EXCEPTION TYPE /iwbep/cx_mgw_tech_exception
EXPORTING
textid = /iwbep/cx_mgw_tech_exception=>changeset_default_violation
method = gcs_methods-changeset_begin.
ENDIF.
CLEAR cv_defer_mode.
ENDMETHOD.
The problem is, in SE80, after the redefinition of /iwbep/if_mgw_appl_srv_runtime~changeset_begin when I try to check that method and activate it, SAP throws this error:
Field GCS_METHODS-CHANGESET_BEGIN is unknown
Can you tell me how can /iwbep/if_mgw_appl_srv_runtime~changeset_begin's redefinition cause such error?
FYI. gcs_methods is a private constant. It might be causing the problem.
A subclass cannot use a private member of its superclass (unless the superclass said the subclass is its friend).
As the superclass is generated, you have to duplicate the constant in your own program.
We had the same issue recently and redefined the method like this:
METHOD /iwbep/if_mgw_core_srv_runtime~changeset_begin.
IF line_exists( it_operation_info[ entity_type = 'ENTITY_TYPE' ] ).
cv_defer_mode = abap_true.
ENDIF.
ENDMETHOD
I'm no expert on this topic, but this implementation fixed our problem.
What the issue with your private constant is, however, I cannot tell.
The error is the inactive methods on the class interface. A simple code check tells all the erros of this implementation.
BR,
I want to read the error messages from messages file but I am unable to. What mistake am I making?
The code where I want to read the string from messages file is
Future { Ok(Json.toJson(JsonResultError(messagesApi("error.incorrectBodyType")(langs.availables(0))))) }
The messages file error.incorrectBodyType=Incorrect body type. Body type must be JSON
The messagesApi("error.incorrectBodyType") should return Incorrect body type. Body type must be JSON but it returns error.incorrectBodyType.
If I remove double quotes in messagesApi(error.incorrectBodyType) then the code doesn't compile
Update
I added a couple of debug prints and notice that the keys I am using in MessagesApi are not defined. I don't know why though as I have created them in messages file.
println("langs array"+langs.availables)
println("app.title"+messagesApi.isDefinedAt("app.title")(langs.availables(0)))
println("error"+messagesApi.isDefinedAt("error.incorrectBodyType")(langs.availables(0)))
prints
langs arrayList(Lang(en_GB))
app.titlefalse
errorfalse
Update 2
I might have found the issue but I don't know how to resolve it. Basically, I am running my test case without an instance of the Application. I am mocking messagesApi by calling stubMessagesApi() defined in Helpers.stubControllerComponents, If I run the same code using an Application eg class UserControllerFunctionalSpec extends PlaySpec with OneAppPerSuiteWithComponents then app.title and error are defined. It seems without an instance of Application, MessagesApi is not using the messages file.
I was able to solve the issue by creating a new instance of MessagesApi using DefaultMessagesApi
val messagesApi = new DefaultMessagesApi( //takes map of maps. the first is the language file, the 2nd is the map between message title and description
Map("en" -> //the language file
Map("error.incorrectBodyType" -> "Incorrect body type. Body type must be JSON") //map between message title and description
)
)
val controller = new UserController(mockUserRepository,mockControllerComponents,mockSilhouette,messagesApi,stubLangs())
I send an entity from an iOS client and it is processed by the following backendAPI method:
#ApiMethod(name="dataInserter.insertData",path="insertData",httpMethod="post")
public Entity insertData(customEntity userInput){
ofy().save().entity(userInput).now();
return userInput;
}
customEntity is defined within customEntity.java as follows:
//Import Statements here
#Entity
public class customEntity {
#Id public String someID;
#Index String providedData;
}
After the above code runs, datastore contains the following entry:
ID/Name providedData
id=5034... <null>
If I add the following lines to my method:
customEntity badSoup=new customEntity();
badSoup.providedData="I am exhausted";
ofy().save().entity(badSoup).now();
I see the following in the datastore after I run the code:
ID/Name providedData
id=5034... I am exhausted
In a post almost similar to this one, the poster -- Drux -- concludes "...assignments to #Indexed properties only have actual effects on indices (and hence queries) if they are carried out directly with Objectify on the server (not indirectly on iOS clients and then passed to the server with Google Cloud Endpoints)." stickfigure then responds, "It sounds like what you're saying is 'cloud endpoints is not reconstituting your SomeEntity object correctly'. Objectify is not involved; it just saves whatever you give it."
It's hard to tell whether stickfigure is correct most especially given the fact that when I explore my API using Google's APIs Explorer, the same problem described above still occurs.
Is anyone able to explain what's causing this or is Drux's conclusion correct?
I am new to Android development with Xamarin.Android and I would like to understand how to have the next issue fixed.
Sometimes after restoring my Android application from background I was facing the next error:
Unable to find the default constructor on type MainMenuFragment. The MainMenuFragment is used by the application NavigationDrawerActivity to allow users to switch between different Fragments inside the app.
In order to solve it, I added a default constructor to the MainMenuFragment as described inside the next links:
Xamarin Limitations - 2.1. Missing constructors
Added a default constructor, should fix the issue.
public class MainMenuFragment : DialogFragment
{
readonly NavigationDrawerActivity navigationDrawer;
#region Constructors
public MainMenuFragment () {} // Default constructor...
public MainMenuFragment (NavigationDrawerActivity navigationDrawer, IMenuType launchMenu = null)
{
if (navigationDrawer == null)
throw new ArgumentNullException ("navigationDrawer");
this.navigationDrawer = navigationDrawer;
...
Fragment UpdateTopFragmentForCurrentMenu (Fragment newMenuRootFragment = null)
{
Fragment currentMenuRootFragment = navigationDrawer.CurrentFragment; // issued line.
But now sometime in the future, the MainMenuFragment gets initialized using its default constructor and at the first time it tries to access its navigationDrawer it throws a System.NullReferenceException:
System.NullReferenceException: Object reference not set to an instance of an object
at MainMenuFragment.UpdateTopFragmentForCurrentMenu (Android.App.Fragment) <0x00018>
at MainMenuFragment.OpenMenu (IMenuType,bool) <0x0006b>
at MainMenuFragment.OnCreate (Android.OS.Bundle) <0x00053>
at Android.App.Fragment.n_OnCreate_Landroid_os_Bundle_ (intptr,intptr,intptr) <0x0005b>
at (wrapper dynamic-method) object.3919a6ec-60c1-49fd-b101-86191363dc45 (intptr,intptr,intptr) <0x00043>
How can I have a default constructor implemented without facing this null reference exception?
You're programming like a C# developer, thats what the problem is :) I faced these same hurdles learning monodroid.
Take a look at the examples out there, in java, you'll see almost all the time they initialize using a static method like object.NewInstance() which returns object. This is how they initialize their views/receivers/fragments. At that point they populate the Arguments property and store that in the fragment. You need to remove all your constructors EXCEPT the empty ones and use arguments to pass your data around. If you try to do this using constructors and regular oo concepts you'll be in for a world of hurt. Arguments.putExtra and all those methods are there. It makes things a little verbose but once you get the hang of it you'll start creating some helper methods etc.
Once you get that sorted, you'll need to figure out if you need to recreate your fragments everytime the activity is resumed and if not, mark them as RetainInstance = true as well as get them onto a fragmentmanager which will help you retain all your state.
If you haven't built on android before it's weird and certainly not what I expected. But it's reeaaallly cool, much more awesome than I expected too. And same with Xamarin.
Great similar question: Best practice for instantiating a new Android Fragment