Error Handling in a web service

Question

Hi,
We are going through the process of producing some test web services, and was wondering if there is a way of handling errors so that a more meaningful message can be output instead of a SOAP Exception.
For example if a number was passed in that was invalid, such as a negative number when only positive would be allowed. Is it possible to output a message that would say something like
'Number input must be positive'
instead of this type of error
[SOAPException: faultCode=SOAP-ENV:Server; msg=ORA-06502: PL/SQL: numeric or value error
ORA-06512: at "CDDEV.SQUARE_ROOT", line 6
ORA-06512: at line 1
     java.lang.String mypackage3.Square_rootStub.get_square_root(java.math.BigDecimal)
          Square_rootStub.java:68
     void mypackage3.Class1.main(java.lang.String[])
          Class1.java:15
This example was done using a PL/SQL web service, but equally using Java if you throw an exception for a negative number you get a NaN type error.
Thanks
Gary

Answer 1

As the error is thrown by the PL/SQL Java wrapper, you possibly could capture it on the server side and throw a more meaningful message. What is happening is that java.sql.SQLException thrown on the server side by the Java PL/SQL wrappers is wrapped into a SOAP fault.
If you were to catch it yourself before propagating it back, you could replace the string. Unfortunately, the java.sql.SQLException is strewn about the generated code so it is hard to isolate - it isn't exactly straight forward. Another avenue to consider might be to wrapper the stored procedure code Java wrapper itself and write your own exception handling where you set the string explicitly (remember the string value set in any exception is what is passed back in the SOAP fault).
None of these are perfect, but perhaps they might give you some ideas ...
Mike.