Unnecessary casting in TypeMapperRegistryImpl ?

Question

Hi,
I was looking at the source code of com.sun.xml.rpc.encoding.TypeMapperRegistryImpl (Sun's implementation of TypeMapperRegistry) at http://www.koders.com/java/fid141228AEE2974D6FBB4640EB03FCFEFC1ACE07B7.aspx
and came across this method :
protected static boolean mappingSupportsEncoding(TypeMapping mapping, String namespaceURI) {
        String[] encodings = ((TypeMappingImpl) mapping).getSupportedEncodings();
        for(int i=0; i<encodings.length; ++i) {
            if (encodings.equals(namespaceURI)) {
return true;
return false;
The TypeMapping interface itself exposes the method getSupportedEncodings(); there is NO NEED to do the cast to TypeMappingImpl. What this casting does is effectively throw a ClassCastException whenever the mapping object is NOT an instance of TypeMappingImpl.
Since this method is called whenever anyone tries to register a new TypeMapping, this is preventing non TypeMapperImpl mappers from being registered.
Is this by design (Cannot think of any reason why) ?? Isn't JAX-RPC supposed to be extensible in terms of encoding (among others) ?
Any help will be greatly appreciated.
Raja

Answer 1

Syntax for casting in OO, is like this.
* References to the objects
  data: r_account type ref to lcl_account.
  data: r_checking type ref to lcl_checking.
* Is the account, a checking account?
   r_checking ?= r_account.
You will learn this when you get to ABAP OO. 
Regards,
Rich Heilman