how to write a webservice that accepts XML document?

Question

Write a webservice that accepts the following XML document as the payload:

<InputDocument>

<DeclarationList>

<Declaration Command="DEFAULT" Version="5.13">

<DeclarationHeader>

<Jurisdiction>IE</Jurisdiction>

<CWProcedure>IMPORT</CWProcedure>

<DeclarationDestination>CUSTOMSWAREIE</DeclarationDestination>

<DocumentRef>71Q0019681</DocumentRef>

<SiteID>DUB</SiteID>

<AccountCode>G0779837</AccountCode>

</DeclarationHeader>

</Declaration>

</DeclarationList>

</InputDocument>

The webservice should respond with a status code which is based on parsing the contents of the XML payload

a. If the XML document is given here is passed then return a status of ‘0’ – which means the document was structured correctly.

b. If the Declararation’s Command <> ‘DEFAULT’ then return ‘-1’ – which means invalid command specified.

c. If the SiteID <> ‘DUB’ then return ‘-2’ – invalid Site specified.