Error message due to getDistanceMatrix Request

Bernd Welter · Post by **Bernd Welter** » Fri Aug 11, 2023 9:37 am

One of my customers faced the following error message while he tried to get a distance matrix from an xServer2:

I was testing api getDistanceMatrix by sending below request as per the documentation
Code: Select all
```
{
  "id": "1352f670-b601-4845-9669-4098368601e3"
}
```

But it shows an error as shown below

{
  "message": "Cannot construct instance of `com.ptvgroup.xserver.xdima.GetDistanceMatrixRequest` (no Creators, like default constructor, exist): abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information\n at [Source: (org.apache.cxf.transport.http.AbstractHTTPDestination$1); line: 3, column: 1]",
  "errorLine": 3,
  "errorColumn": 1,
  "faultType": "com.ptvgroup.xserver.exceptions.InvalidRequestFault"
}

So this is a quite generic message and I get asked for this very often because it happens in many requests:

The xDima2.GetDistanceMatrixRequest is an abstract class which you can't instanciate.

Taken from the API doc of GetDistanceMatrixRequest
Instead you have to use one of it's derived child classes - in this case either GetDistanceMatrixByLocationsRequest or GetDistanceMatrixByRelationsRequest
For the JSON request this means that you have to qualify the type, e.g. the GetDistanceMatrixByLocationsRequest:
Code: Select all
```
{
  "id": "1352f670-b601-4845-9669-4098368601e3",
  "$type": "GetDistanceMatrixByLocationsRequest"
}
```

This will then lead to the next obstacle: the specific class requires two attributes which are supposed to be given...

Code: Select all

{
  "faultInfo": {
    "$type": "InvalidValueFault",
    "hint": "Affects field 'startLocations' in 'GetDistanceMatrixByLocationsRequest'.",
    "parameter": "/GetDistanceMatrixByLocationsRequest/startLocations"
  },
  "message": "List must have at least 1 item(s) but was missing."
}

So to get rid of this second error please ensure to provide all required parameters of the child class in use

This also happens in the following request types (just a selection - there may be even more):

Bernd