Exception Handling

[siraj baig]

In my .wsdl file i am restricting some vehicles according to requirements.

<xsd:simpleType name="VehicleType">
<xsd:restriction base="xsd:string">
<xsd:enumeration value="sedan"/>
<xsd:enumeration value="suv"/>
</xsd:restriction>
</xsd:simpleType>

If the user provides other than these vehicles server throws exception which no one can understand what is that exception.
I want to send a meaningful message to the user saying " vehicle not allowed" ..

Can you tell me How to Handle the Exception

Thanks for your response
siraj

[vikram karne]

Hi sairaj

For you to send any useful message to the user you have to create your own exception type in your code first. you can then use this exception in your handler class where you can instantiate it to send a useful message to the user.
i think you may have to embed that exception type in your .wsdl file if you are hand editing the wsdl other wise it can be directly generated from the .wsdd file.
rest you can refer any sample .wsdl file on the net.

hope this is useful

Regards
Vikram K

[siraj baig]

Hi vikram,
I have already exception class defined and throwing in my handler.
But the problam is the request is not going till that point(handler).
At the ui level itself is breaking me.

[Peer Reynders]

Originally posted by siraj baig:
server throws exception which no one can understand what is that exception.

Are you certain that the server actually generates a SOAP fault which is then translated on the client side to an exception?

But the problam is the request is not going till that point(handler). At the ui level itself is breaking me

This suggests that the request is never sent. The error on the enumeration could be detected by the client side marshalling code that was generated by the client wsdl-to-java tool. So the exception would be generated entirely on the client side - the request would never be completely built and couldn�t reach the client or server handler chain. Web service toolkits often throw exceptions similar to those based on actual SOAP faults even if there is no SOAP fault present in order to "unify their exception interface".

If that is the case then you have handle this entirely on the client side. Catch the exception thrown by the client stub method and then throw your own exception class.

[siraj baig]

Hi Peer,
Can you tell me how to catch the exception at client side and throw
meaningful exception.
please provide sample code.

Thanks for your response
siraj.

[Peer Reynders]

Example Axis 1.3
WSDL:

<?xml version="1.0" encoding="UTF-8"?>
<definitions
  name="XmlEnum" 
  targetNamespace="http://ws.javaranch.com/wsdl/xml_enum" 
  xmlns="http://schemas.xmlsoap.org/wsdl/"
  xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
  xmlns:tns="http://ws.javaranch.com/wsdl/xml_enum" 
  xmlns:soapbind="http://schemas.xmlsoap.org/wsdl/soap/">
 
  <types>
    <schema elementFormDefault="qualified"
      targetNamespace="http://ws.javaranch.com/wsdl/xml_enum"
      xmlns:tns="http://ws.javaranch.com/wsdl/xml_enum"
      xmlns="http://www.w3.org/2001/XMLSchema"> 
 
       <xsd:simpleType name="VehicleType">
         <xsd:restriction base="xsd:string">
           <xsd:enumeration value="sedan"/>
           <xsd:enumeration value="suv"/>
        </xsd:restriction>
      </xsd:simpleType>
       
      <element name="Vehicle" type="tns:VehicleType"/>          
      <element name="VehicleResponse" type="xsd:string"/>          
    </schema>
  </types>
 
  <message name="VehicleMessage">
    <part name="parameter" element="tns:Vehicle"/>
  </message>
  <message name="VehicleMessageResponse">
    <part name="parameter" element="tns:VehicleResponse"/>
  </message>
 
  <portType name="VehiclePort">
    <operation name="echoVehicle">
      <input name="input" message="tns:VehicleMessage"/>
      <output name="output" message="tns:VehicleMessageResponse"/>
    </operation>
  </portType>
 
  <binding name="VehicleBinding" type="tns:VehiclePort">
    <soapbind:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/>
    <operation name="echoVehicle">
      <soapbind:operation soapAction="http://ws.javaranch.com/wsdl/xml_enum/actions/echoVehicle"/>
      <input>
        <soapbind:body use="literal"/>
      </input>
      <output>
        <soapbind:body use="literal"/>
      </output>
    </operation>
  </binding>
 
  <service name="VehicleService">
    <port name="vehicleservice" binding="tns:VehicleBinding">
      <soapbind:address location="http://localhost:8080/axis/services/vehicleservice"/>
    </port>
  </service>
</definitions>

Interface after WSDL2Java:

public interface VehiclePort extends java.rmi.Remote {
    public java.lang.String echoVehicle(
        xmlenum.ws.VehicleType parameter
    ) throws java.rmi.RemoteException;
}

Custom Checked Exception:

package xmlenum;
 
public class InvalidVehicleTypeException extends Exception {
 
    static private String makeMessage(String invalidType){
        return "\"" + invalidType + "\" is not a valid vehicle type.";
    }
    
    public InvalidVehicleTypeException(String invalidType, Throwable cause){
        super(makeMessage(invalidType), cause);
    }
    
    public InvalidVehicleTypeException(String invalidType){
        super(makeMessage(invalidType));
    }
 
    public InvalidVehicleTypeException(Throwable cause){
        super(cause);
    }
 
    public InvalidVehicleTypeException(){
        super();
    }    
}

Command line client:

package xmlenum;
 
import xmlenum.ws.VehicleServiceLocator;
import xmlenum.ws.VehiclePort;
import xmlenum.ws.VehicleType;
 
public class XmlEnumTester {
    public static void main(String [] args) throws Exception {
        VehicleServiceLocator   locator     = new VehicleServiceLocator();
        VehiclePort             port        = locator.getvehicleservice();
//      String                  typeValue   = "sedan";  // american english
        String                  typeValue   = "saloon"; // british english 
        try {
            // this is the line that throws a java.lang.IllegalArgumentException
            VehicleType         type        = VehicleType.fromValue(typeValue);
            String              response    = port.echoVehicle(type);
            System.out.println( "Response: " + response );        
 
        } catch (java.lang.IllegalArgumentException iae) {
            throw new InvalidVehicleTypeException( typeValue, iae );
            
        } catch (org.apache.axis.AxisFault e) {
            javax.xml.namespace.QName name = e.getFaultCode();
 
            System.out.println( "Fault Code:   " + name.toString() );        
            System.out.println( "Fault String: " + e.getFaultString() );        
            System.out.println( "Fault Actor: "  + e.getFaultActor() );        
        }
    }
}

Resulting exception:

Exception in thread "main" xmlenum.InvalidVehicleTypeException: "saloon" is not a valid vehicle type.
at xmlenum.XmlEnumTester.main(XmlEnumTester.java:22)
Caused by: java.lang.IllegalArgumentException
at xmlenum.ws.VehicleType.fromValue(VehicleType.java:29)
at xmlenum.XmlEnumTester.main(XmlEnumTester.java:17)