[SalesForce] wsdl2apex class and System.NullPointerException: Attempt to de-reference a null object

I am trying to connect to a weather API.

The class was created from wsdl2apex

public class AsyncWeatherRequestWebService2 {
public class GetCitiesByCountryResponse_elementFuture extends System.WebServiceCalloutFuture {
    public String getValue() {
        WeatherRequestWebService2.GetCitiesByCountryResponse_element response = (WeatherRequestWebService2.GetCitiesByCountryResponse_element)System.WebServiceCallout.endInvoke(this);
        return response.GetCitiesByCountryResult;
    }
}
public class GetWeatherResponse_elementFuture extends System.WebServiceCalloutFuture {
    public String getValue() {
        WeatherRequestWebService2.GetWeatherResponse_element response = (WeatherRequestWebService2.GetWeatherResponse_element)System.WebServiceCallout.endInvoke(this);
        return response.GetWeatherResult;
    }
}
public class AsyncGlobalWeatherSoap {
    public String endpoint_x = 'http://www.webservicex.net/globalweather.asmx';
    public Map<String,String> inputHttpHeaders_x;
    public String clientCertName_x;
    public Integer timeout_x;
    private String[] ns_map_type_info = new String[]{'http://www.webserviceX.NET', 'WeatherRequestWebService2'};
    public AsyncWeatherRequestWebService2.GetCitiesByCountryResponse_elementFuture beginGetCitiesByCountry(System.Continuation continuation,String CountryName) {
        WeatherRequestWebService2.GetCitiesByCountry_element request_x = new WeatherRequestWebService2.GetCitiesByCountry_element();
        request_x.CountryName = CountryName;
        return (AsyncWeatherRequestWebService2.GetCitiesByCountryResponse_elementFuture) System.WebServiceCallout.beginInvoke(
          this,
          request_x,
          AsyncWeatherRequestWebService2.GetCitiesByCountryResponse_elementFuture.class,
          continuation,
          new String[]{endpoint_x,
          'http://www.webserviceX.NET/GetCitiesByCountry',
          'http://www.webserviceX.NET',
          'GetCitiesByCountry',
          'http://www.webserviceX.NET',
          'GetCitiesByCountryResponse',
          'WeatherRequestWebService2.GetCitiesByCountryResponse_element'}
        );
    }
    public AsyncWeatherRequestWebService2.GetWeatherResponse_elementFuture beginGetWeather(System.Continuation continuation,String CityName,String CountryName) {
        WeatherRequestWebService2.GetWeather_element request_x = new WeatherRequestWebService2.GetWeather_element();
        request_x.CityName = CityName;
        request_x.CountryName = CountryName;
        return (AsyncWeatherRequestWebService2.GetWeatherResponse_elementFuture) System.WebServiceCallout.beginInvoke(
          this,
          request_x,
          AsyncWeatherRequestWebService2.GetWeatherResponse_elementFuture.class,
          continuation,
          new String[]{endpoint_x,
          'http://www.webserviceX.NET/GetWeather',
          'http://www.webserviceX.NET',
          'GetWeather',
          'http://www.webserviceX.NET',
          'GetWeatherResponse',
          'WeatherRequestWebService2.GetWeatherResponse_element'}
        );
    }
}

}

I am just testing this using the execute anonymous window

AsyncWeatherRequestWebService2.GetWeatherResponse_elementFuture GetWeatherRequestService;

 AsyncWeatherRequestWebService2.AsyncGlobalWeatherSoap GetWeatherRequest = new AsyncWeatherRequestWebService2.AsyncGlobalWeatherSoap();   

 Integer TIMEOUT_INT_SECS = 90;  
 Continuation cont = new Continuation(TIMEOUT_INT_SECS);
 cont.continuationMethod = 'processResponse';     


GetWeatherRequestService = GetWeatherRequest.beginGetWeather(cont, 'Paris','france'); 

GetWeatherRequestService.getValue();

and the error i am receiving is System.NullPointerException: Attempt to de-reference a null object pointing to return response.GetWeatherResult;

when i test the webservice using SOAPUI, it does return something.

so is this issue in the way i am calling the webservice? is the generated class missing something?

help please!

It is probably because of the
"cont.continuationMethod = 'processResponse'; "

does it require a call back method?

public Object processResponse() {
result = GetWeatherRequestService.getValue();
return result;

Best Answer

Wsdl2Apex now creates two sets of Apex classes for interacting with the SOAP based web service.

The first use WebServiceCallout.invoke and are synchronous. These are historically all that were generated.
The second use what is called a Continuation. These are new in Spring 15. See Make Long-Running Callouts from a Visualforce Page. It will use WebServiceCallout.beginInvoke and WebServiceCallout.endInvoke calls

For the purposes of testing the web service via anonymous apex you will want to use the former. It will have a name like WeatherRequestWebService2 based on your sample code.

E.g. (After adding Remote Sites setting for http://www.webservicex.net)

wwwWebservicexNet.GlobalWeatherSoap ws = new wwwWebservicexNet.GlobalWeatherSoap();

//System.debug(ws.GetCitiesByCountry('France'));

string weather = ws.GetWeather('Paris / Le Bourget', 'France');
System.debug(weather);

Gives:

<?xml version="1.0" encoding="utf-16"?>
<CurrentWeather>
  <Location>Paris / Le Bourget, France (LFPB) 48-58N 002-27E 65M</Location>
  <Time>Apr 28, 2015 - 07:00 PM EDT / 2015.04.28 2300 UTC</Time>
  <Wind> from the N (010 degrees) at 5 MPH (4 KT):0</Wind>
  <Visibility> greater than 7 mile(s):0</Visibility>
  <Temperature> 42 F (6 C)</Temperature>
  <DewPoint> 35 F (2 C)</DewPoint>
  <RelativeHumidity> 75%</RelativeHumidity>
  <Pressure> 30.15 in. Hg (1021 hPa)</Pressure>
  <Status>Success</Status>
</CurrentWeather>

Related Solutions

[SalesForce] Asynchronous Callout from an Imported WSDL

I've just heard back from my support case. This is now a Known Issue - Running Test for WSDL-based asynchronous callouts fails with Internal Salesforce.com Error

I've cross posted this to the developer forums as a bug - WSDL-Based Asynchronous Callouts using Continuations can't be unit tested.

As a short term work around, you can use Test.isRunningTest() strategically within the generated AsyncWwwParasoftComWsdlCalculator class to avoid the actual callouts.

E.g.

public class multiplyResponse_elementFuture extends System.WebServiceCalloutFuture {
    public Double getValue() {
        if(Test.isRunningTest()) { return 7; } // Hard coded Mock Response
        wwwParasoftComWsdlCalculator.multiplyResponse_element response = (wwwParasoftComWsdlCalculator.multiplyResponse_element)System.WebServiceCallout.endInvoke(this);
        return response.Result;
    }
}

//...

    public AsyncWwwParasoftComWsdlCalculator.addResponse_elementFuture beginAdd(System.Continuation continuation,Double x,Double y) {
        wwwParasoftComWsdlCalculator.add_element request_x = new wwwParasoftComWsdlCalculator.add_element();
        request_x.x = x;
        request_x.y = y;

        if(Test.isRunningTest()) {
            // Prevent the actual callout during testing
            return new AsyncWwwParasoftComWsdlCalculator.addResponse_elementFuture();
        }

        return (AsyncWwwParasoftComWsdlCalculator.addResponse_elementFuture) System.WebServiceCallout.beginInvoke(
          this,
          request_x,
          AsyncWwwParasoftComWsdlCalculator.addResponse_elementFuture.class,
          continuation,
          new String[]{endpoint_x,
          'add',
          'http://www.parasoft.com/wsdl/calculator/',
          'add',
          'http://www.parasoft.com/wsdl/calculator/',
          'addResponse',
          'wwwParasoftComWsdlCalculator.addResponse_element'}
        );
    }

You will need to drop the test assertion based on the size of the Continuation.getRequests() Map.

I've found that the WebServiceMock most likely isn't working as the response parameter to doInvoke is null. Without this Map<String, Object> you can't specify the return response.

E.g. The mock should be doing something like:

public void doInvoke(
   Object stub,
   Object request,
   Map<String, Object> response,
   String endpoint,
   String soapAction,
   String requestName,
   String responseNS,
   String responseName,
   String responseType) {

       System.debug(LoggingLevel.INFO, 'eloWsm.doInvoke() - ' +
                                 //'\n stub: ' + stub +
                                 '\n request: ' + request +
                                 '\n response: ' + response +
                                 '\n endpoint: ' + endpoint +
                                 '\n soapAction: ' + soapAction +
                                 '\n requestName: ' + requestName +
                                 '\n responseNS: ' + responseNS +
                                 '\n responseName: ' + responseName +
                                 '\n responseType: ' + responseType);

       wwwParasoftComWsdlCalculator.addResponse_element res = new wwwParasoftComWsdlCalculator.addResponse_element();
       res.Result = 7.0;

       response.put('response_x', res);

   }

However, this is throwing the following exception because response is null:

System.NullPointerException: Attempt to de-reference a null object

The example from Testing WSDL-Based Asynchronous Callouts doesn't make any use of WebServiceMock, so in theory it should work without it.

I've confirmed your findings that leaving it out retults in:

System.TypeException: Methods defined as TestMethod do not support Web service callouts, test skipped

[SalesForce] Named Credentials in wsdl2apex Class

UPDATE for Winter `16 - Simplify Development of Web Service Callouts by Using Named Credentials

Short answer. No, it doesn't appear Named Credentials are supported by Wsdl2Apex.

I created minimal Named Credential for a public webservicex web service that doesn't require authentication (to check if it will work for the endpoint URL).

enter image description here

Then I tried to change the wsdl2Apex generated classes endpoint_x to use it.

wwwWebservicexNet.GlobalWeatherSoap ws = new wwwWebservicexNet.GlobalWeatherSoap();
ws.endpoint_x = 'callout:webservicex';

string weather = ws.GetWeather('Paris / Le Bourget', 'France');
System.debug(weather);

This gives:

System.CalloutException: IO Exception: unknown protocol: callout

In the past I've used protected custom settings within a managed package to store the credentials that are passed to a SOAP web service. As a hierarchy setting I can store Org, Profile, or User level credentials. When deployed as a managed package the credentials can only be accessed by the Apex defined within the package (this includes setting the values as well as retrieval).

Out of interest, I used the FuseIT SFDC Explorer (Disclosure: Made by my current employer) to generate a method from the WSDL that uses HttpRequest and a manual SOAP body rather than WebServiceCallout.invoke.

wwwWebservicexNet.GlobalWeatherSoap ws = new wwwWebservicexNet.GlobalWeatherSoap();
ws.endpoint_x = 'callout:webservicex';
string weather = ws.GetWeather_Http('Paris / Le Bourget', 'France');
System.debug(weather);

Success!

enter image description here

This isn't really Wsdl2Apex anymore as it is using an HttpRequest. It is however calling the SOAP based web service from Salesforce using details stored in a Named Credential.

Best Answer

Related Solutions

[SalesForce] Asynchronous Callout from an Imported WSDL

[SalesForce] Named Credentials in wsdl2apex Class

Related Topic