I'm new to Jruby and currently working on an app needs to convert Java code to Jruby for JMS client, here is the code in java:
connection.setExceptionListener(ExceptionListener.new() {
public void onException (JMSException ex) {
connection = null;
}
})
Can anyone give me some idea how to convert this to Jruby? Thanks.
first of all that is not valid Java code maybe this is :
connection.setExceptionListener(new ExceptionListener() {
public void onException(JMSException ex) {
connection = null;
}
})
... depends on the ExceptionListener lets assume its a functional-interface with a single onException method in which case you can use the (magical) block-to-interface conversion :
connection.setExceptionListener { |ex| connection = nil }
Related
I am running dotnet core 2.* and as the title mentions I have trouble getting my try catch to work when calling from API. And before anyone comments I am also running middle-ware to catch any exceptions. It too doesn't perform as expected
Addinional Information:
The Two Classes are in different namespaces/projects
Queries.Authentication is static.
They are both in the same solution
Controller:
[AllowAnonymous]
[HttpPost]
public string Login([FromBody] AuthRequest req)
{
// See if the user exists
if (Authenticate(req.username, req.password))
{
try {
// Should Fail Below
UserDetails ud = Queries.Authentication.GetUser(req.username);
} catch (RetrievalException e){ }
catch (Exception e){ } // Exception Still Comes Through
}
}
Queries.Authentication.GetUser Code:
public static class Authentication {
public static UserDetails GetUser (string username)
{
// Some Code
if (details.success)
{
// Some Code
}
else
{
throw new RetrievalException(details.errorMessage); // This is not caught propperly
}
}
}
Retrieval Exception:
public class RetrievalException : Exception
{
public RetrievalException()
{
}
public RetrievalException(String message)
: base(message)
{
}
public RetrievalException(String message, Exception inner)
: base(message, inner)
{
}
}
EDIT: Adding Middleware Code Here as per request:
public class CustomExceptionFilter : IExceptionFilter
{
public void OnException(ExceptionContext context)
{
HttpStatusCode status = HttpStatusCode.InternalServerError;
String message = String.Empty;
var exceptionType = context.Exception.GetType();
if (exceptionType == typeof(UnauthorizedAccessException))
{
message = "Unauthorized Access";
status = HttpStatusCode.Unauthorized;
}
else if (exceptionType == typeof(NullReferenceException))
{
message = "Null Reference Exception";
status = HttpStatusCode.InternalServerError;
}
else if (exceptionType == typeof(NotImplementedException))
{
message = "A server error occurred.";
status = HttpStatusCode.NotImplemented;
}
else if (exceptionType == typeof(RSClientCore.RetrievalException))
{
message = " The User could not be found.";
status = HttpStatusCode.NotFound;
}
else
{
message = context.Exception.Message;
status = HttpStatusCode.NotFound;
}
context.ExceptionHandled = true;
HttpResponse response = context.HttpContext.Response;
response.StatusCode = (int)status;
response.ContentType = "application/json";
var err = "{\"message\":\"" + message + "\",\"code\" :\""+ (int)status + "\"}";
response.WriteAsync(err);
}
}
App Config:
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
} else
{
app.UseExceptionHandler();
}
...
}
Service Config:
public void ConfigureServices(IServiceCollection services)
{
// Add Model View Controller Support
services.AddMvc( config =>
config.Filters.Add(typeof (CustomExceptionFilter))
);
UPDATE: After playing around with it I noticed that even though my program throws the exception, if I press continue the API controller then handles it as if the exception was never thrown (as in it catches it and does what I want). So I turned off the break on Exception setting, this fixed it in debugger mode. However this the break doesn't seem to be an issue when I build/publish the program. This makes me think it is definitely a issue with visual studio itself rather than the code.
When you set ExceptionHandled to true that means you have handled the exception and there is kind of no error anymore. So try to set it to false.
context.ExceptionHandled = false;
I agree it looks a bit confusing, but should do the trick you need.
Relevant notes:
For those who deal with different MVC and API controller make sure you implemented appropriate IExceptionFilter as there are two of them - System.Web.Mvc.IExceptionFilter (for MVC) and System.Web.Http.Filters.IExceptionFilter (for API).
There is a nice article about Error Handling and ExceptionFilter Dependency Injection for ASP.NET Core APIs you could use as a guide for implementing exception filters.
Also have a look at documentation: Filters in ASP.NET Core (note selector above the left page menu to select ASP.NET Core 1.0, ASP.NET Core 1.1,ASP.NET Core 2.0, or ASP.NET Core 2.1 RC1). It has many important notes and explanations why it works as it does.
In my current application i have a service which uses a saxparser to read some xml. In saxparser i try to store a new objectto the database but i get the following error:
ERROR util.JDBCExceptionReporter - Connection is read-only. Queries leading to data modification are not allowed
My Service looks like so:
#Transactional
class SchedulingService {
def printIets() {
LessonParser par = new LessonParser()
print "de service macheert ier e trut"
par.parse(["src/data/tweede/"])
}
}
The parser:
class LessonParser {
public void parse(baseFileLocations){
....
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser = factory.newSAXParser();
LessonHandler handler = new LessonHandler()
saxParser.parse(is, handler);
...
}
}
And finally the handler where the attempt to save something to the database is made
class LessonHandler extends DefaultHandler{
#Override
public void endElement(String uri, String localName, String qName) throws SAXException {
if (qName.equalsIgnoreCase("TTSession")) {
//voorlopig enkel hoorcolleges
if (parse && this.courseType == CourseType.HC) {
Course course = new Course (name:this.name , info:this.info,courseType:this.courseType,creator:this.creator)
course.save()
}
}
}
}
The error occurs when i try to save a course in the above handler.
Also i'm using a mysql database
I had connected the service to a restful api, i forgot an #transactional definition there. Adding it did the trick
Thanks for sharing.
the service got a "#Transactional(readOnly = true)" definition. So all the methods will be read only.
If you want to do some modification, you need to add "#Transactional" before the method.
I'm a little bit new to all of these technologies so I'll try to be as clear as I can.
I'm writing a windows phone app that sends data in string format to a server:
public class sendDataControl
{
private string response = "";
public void sendToServer(string FullSTR)
{
try
{
WebClient webClient = new WebClient();
Uri uri = new Uri("http://pricequeryserver.azurewebsites.net/api/ReceiptDataService/?incomingdata=");
webClient.UploadStringAsync(uri,FullSTR);
webClient.UploadStringCompleted += new UploadStringCompletedEventHandler(webClient_UploadStringCompleted);
}
catch (Exception ex)
...
...
}
}
void webClient_UploadStringCompleted(object sender, UploadStringCompletedEventArgs e)
{
if (e.Error != null)
{
responseXml=e.Error.Message;
MessageBox.Show(responseXml);
return;
}
else
{
responseXml = e.Result;
}
}
}
The server is an MVC4, basic, with api controller I added, that needs to get the data sent from the mobile.
As a test I'm just getting back a string that I send:
public class ReceiptDataServiceController : ApiController
{
private ReceiptContext db = new ReceiptContext();
...
...
public string GetDataFromMobile(string IncomingData)
{
return IncomingData;
}
}
While running the application I get an error via responseXml:
"The remote server returned an error: NotFound".
The server returns the right answer from all kinds of browsers, while on IIS and on the azure but not from the mobile emulator.
Any suggestions?
If you take a look at the documentation for UploadStringAsync overload you are using, you will notice that it sends data using POST method. While in your controller you have only implemented GET. And for your
You have to use other overload of UploadStringAsync, which lets you specify the HTTP VERB to use. And you must specify GET. Your client code should be converted to:
webClient.UploadStringAsync(uri,"GET", FullSTR);
And the best solution for simple GET operations like your is to actually use DownloadStringAsync:
var fullUri = new Uri("http://pricequeryserver.azurewebsites.net/api/ReceiptDataService/?incomingdata=" + FullStr);
webClient.DownloadStringAsync(fullUri);
Anyway, your question has nothing to do with Windows Azure, thus the removed tag.
Using Play Framework 2.1 with OpenID, if I cancel my authentication from the OpenID Provider, I get this exception :
[RuntimeException: play.api.libs.openid.Errors$AUTH_CANCEL$]
Here's my code :
Promise<UserInfo> userInfoPromise = OpenID.verifiedId();
UserInfo userInfo = userInfoPromise.get(); // Exception thrown here
But since it's a Runtime exception, I can't catch it with a try/catch so I'm stuck on how to avoid exception and returns something nicer than a server error to the client.
How can I do that?
A Promise is success biased, for all its operations, it assumes it actually contains a value and not an error.
You get the exception because you try to call get on a promise which contains an untransformed error.
What you want is to determine if the Promise is a success or an error, you can do that with pattern matching for instance.
try this code:
AsyncResult(
OpenID.verifiedId.extend1( _ match {
case Redeemed(info) => Ok(info.attributes.get("email").getOrElse("no email in valid response"))
case Thrown(throwable) => {
Logger.error("openid callback error",throwable)
Unauthorized
}
}
)
)
You may want to read more on future and promises, I recommend this excellent article :
http://danielwestheide.com/blog/2013/01/09/the-neophytes-guide-to-scala-part-8-welcome-to-the-future.html
edit :
checking the documentation (http://www.playframework.com/documentation/2.1.0/JavaOpenID) in java it seems you are supposed to catch and handle exceptions yourself.
In any case, you should catch exceptions and if one is thrown redirect
back the user to the login page with relevant information.
something like this should work :
public class Application extends Controller {
public static Result index() {
return ok("welcome");
}
public static Result auth() {
Map<String, String> attributes = new HashMap<String, String>();
attributes.put("email", "http://schema.openid.net/contact/email");
final Promise<String> stringPromise = OpenID.redirectURL("https://www.google.com/accounts/o8/id", "http://localhost:9000/auth/callback",attributes);
return redirect(stringPromise.get());
}
public static Result callback() {
try{
Promise<UserInfo> userInfoPromise = OpenID.verifiedId();
final UserInfo userInfo = userInfoPromise.get();
System.out.println("id:"+userInfo.id);
System.out.println("email:"+userInfo.attributes.get("email"));
return ok(userInfo.attributes.toString());
} catch (Throwable e) {
System.out.println(e.getMessage());
e.printStackTrace();
return unauthorized();
}
}
}
I created a Remote Procedure Call. The Server-Side connects to Webservices, to get Information, which it hands over to the Client-Side. This is the Client-Side Code.
public void statusFor(GwtLaneServiceAsync laneProxy){
AsyncCallback<LaneInformation> callback = new AsyncCallback<LaneInformation>()
{
#Override
public void onFailure(Throwable caught)
{
}
#Override
public void onSuccess(LaneInformation information)
{
doStatusForSuccess(information);
}
};
for (Lane lane : this.mainmenu.getSlidePanel().getLaneMenu().getProperLanes().values())
{
if (lane.isChecked().booleanValue())
laneProxy.statusFor("admin", "password", true, lane.getId(), callback);
else
laneProxy.statusFor("admin", "password", false, lane.getId(), callback);
this.laneIndex++;
}
}
Now i wanna do the following...
When the Server can't reach the Webservice, a WebServiceException is thrown. If that happens, I wanna type "Offline" on one of my Buttons of the GUI. BUT I need to tell on which button. It can't be hard coded, cause it depends on which "lane" the Webservice failed.
I need to catch the Exceptions
I need to tell the "onFailure"-Part, on which lane, the Service failed.
Can I somehow deliver the statusFor()-Parameters to that part?
There is no of ways to handle such case. you can throw any custom exception from server side while server can't reach the webservice. then it will come onFailure block. or you can return any message string in response variable. Here response variable you are using LaneInformation bean. so take new variable there like result, and set message as per your requirement.
OnFailure it comes only when any exception occurred or any wrong thing happens in RPC call.
Why not wrap your LaneInformation in a generic response object and add the exception/an error code to that response, to signal that something went wrong on the server side, eg.:
public class RemoteResult<T>
{
T payload;
String errorCode;
}
and
public abstract class AbstractAsyncCallBack<T> implements AsyncCallback<RemoteResult<T>>
{
public void onSuccess( RemoteResult<T> rr )
{
if ( rr.getErrrorCode() != null ) { failure( rr.getErrorCode() ); }
else { success( rr.getPayload() ); }
}
public abstract void success( T payload );
public void failure( String errorCode ) { /* Ignore by default */ }
}
To conclude, you shouldn't throw an exception on the server side when the server can't connect to some other service, you should communicate that nicely to the client, and that's not by (re)throwing the exception :-)
The onFailure() method is mostly for when things go wrong in the RPC communication proper.
Cheers,