Monthly Archives: March 2011

Reading WSDL

11 Friday Mar 2011

Posted by in Java, SOA

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While SOA offers all the goodies of loose-coupling, it does require understanding of some basic concepts and formats.
SOAP and WSDL are the prime candidates (or culprits, depending on your view)

SOAP is just a protocol for passing information, important is WSDL.

A WSDL(Web Service Description Language) file defines the contract for web service. It is just like the menu in a restaurant or a table of contents of a book. It tells about what is offered.

Without wasting more time, lets just get to work – understanding WSDL.

A WSDL file may be provided to you or it can generally be accessed by appending “?wsdl” at the end of a web service address.

A WSDL file is best-read bottom-up. It consists of abstract as well as concrete parts. Important parts to focus are (concrete)-

  • wsdl:service – this is the tag which tells you about the name of the service. Consider it synonymous with class file.
  • wsdl:port or port – this tag tells about the place where you can connect to. There can be multiple ports. Each port will have an “address” element. The location attribute specifies the endpoint address of the service. Pay attention the binding attribute of the port.
  • wsdl:binding – this tag refers to the actual implementation of the service. It’ll be further up in the wsdl document. It contains the methods of the service.
  • wsdl:operation – this tag refers to the operations provided by the port. wsdl:operation will contain soap:operation or similar tag depending on the binding.
  • wsdl:input and wsdl:output – specifies the form of input/output. This is because it can be either literal or encoded.

Now focus on the Type attribute of the wsdl:binding, and trace it up in the document. It leads you to portType element. portType is the abstract part of the wsdl.

  • portType – is something like an Interface, in fact it is called as interface in wsdl 2.0. It’ll have a no. of operations.
  • operation – specifies input and output message variable types. These types are specified further up in the wsdl.

Call Oracle PL/SQL procedure with XMLType from Java using JDBC

11 Friday Mar 2011

Posted by in Database, Integration, Java, Oracle

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Recently I needed to call a stored procedure which had Oracle’s XMLType as IN and OUT parameters.

The first thing to do is add xdb.jar and xmlparserv2.jar file to your application lib. These contain the required class files for Oracle XML API. the jars can be found under your installation of oracle client lib folders. Also don’t forget to add oracle jdbc driver files – ojdbc6 or ojdbc14.

The code I setup was this –

XMLType reqInXml;
XMLType reqOutXML;
String atpInStr = "";
OpResponse output = null;

try {
   reqInStr = jaxbMarshalRequestToString(input);
   System.out.println("Input : " + reqInStr);
} catch (JAXBException ex) {
   logger.log(Level.SEVERE, null, ex);
} catch (IOException ex) {
   logger.log(Level.SEVERE, null, ex);
}

//input.getHeader().setNotes("THIS VALUE RETURNED BY FACADE : " + XXDS);
try {
   Connection con = XXDS.getConnection();
   //The IN parameter for stored proc is Oracle XDB XMLType
   reqInXml = XMLType.createXML(con, reqInStr);
   OracleCallableStatement stmt = (OracleCallableStatement) con.prepareCall("call DEMO_PROC.ProcessXMLRequest(?, ?, ?, ?)");
   stmt.setObject(1, reqInXml);

   //set out parameters
   stmt.registerOutParameter (2, OracleTypes.OPAQUE,"SYS.XMLTYPE");
   stmt.registerOutParameter(3, Types.INTEGER);
   stmt.registerOutParameter(4, Types.VARCHAR);

   stmt.executeQuery();
   int resultCode = stmt.getInt(3);
   String resultMsg = stmt.getString(4);
   System.out.println("result code : " + resultCode);
   System.out.println("result msg : " + resultMsg);
   if (resultCode == 101 || resultCode == 100){
      reqOutXML = XMLType.createXML(stmt.getOPAQUE(2));
      System.out.println("Output from ERP :" + reqOutXML.getStringVal());
      output = jaxbUnmarshalFromString(reqOutXML.getStringVal());
   }
}
....

This gave me “java.lang.ClassCastException: com.sun.gjc.spi.jdbc40.ConnectionHolder40 cannot
be cast to oracle.jdbc.OracleConnection” Exception. The connection was being returned from GlassFish JDBC ConnectionPool and was instance of OracleConnectionPooldataSource.
The FIX proved tricky, but in the end it was simple –
Do this –

OracleConnection oraCon = con.unwrap(OracleConnection.class);
//The IN parameter for stored proc is Oracle XDB XMLType
atpInXml = XMLType.createXML(oraCon, atpInStr);

Pass the cast instance of OracleConnection to the XMLType API.