AbstractStaxStreamPayloadEndpoint still not working

[lasse_stromberg]

Hi!
This is my test code to parse a request message and create a response with
an AbstractStaxStreamPayloadEndpoint:

 public class OfficeRegisterWSEndpoint extends AbstractStaxStreamPayloadEndpoint {

   protected void invokeInternal(XMLStreamReader streamReader, XMLStreamWriter streamWriter) {

        try {
            while (streamReader.hasNext()) {
                int event = streamReader.next();
                switch (event) {
                case XMLStreamConstants.END_DOCUMENT:
                    streamReader.close();
                    break;
                case XMLStreamConstants.START_ELEMENT:
                    if (streamReader.getLocalName().equals("officeId")) {
                        event = streamReader.next();
                        if (event == XMLStreamConstants.CHARACTERS) {
                            if (!streamReader.isWhiteSpace())
                            Long officeId = Long.valueOf(streamReader.getText());
                            //call a servie method with id
                            createResponse(streamWriter);
                            return;
                        }
                    }
                default:
                    break;
                }
            }
        } catch (XMLStreamException e) {
            e.printStackTrace();
        }
    }

    private void createResponse(XMLStreamWriter writer) {
        
        try {
        writer.writeStartElement("TestResponse");
        writer.writeStartElement("TestElement");
        writer.writeCharacters("xyz");
        writer.writeEndElement();
        writer.writeEndElement();    
        writer.flush();
        writer.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

Parsing of the message works fine but writing the response fails somehow.
No response is created at all. There are no exceptions in the log or on stdout but i guess somewhere an exception is silently caught and not treated or logged.
thx & regards!

[lasse_stromberg]

Ok i found a workaround for my problem...

From AbstractStaxStreamPayloadEndpoint:

private XMLStreamWriter getStreamWriter(Result result) {
        XMLStreamWriter streamWriter = null;
        if (result instanceof StaxResult) {
            StaxResult staxResult = (StaxResult) result;
            streamWriter = staxResult.getXMLStreamWriter();
        }
        if (streamWriter == null) {
            try {
                streamWriter = getOutputFactory().createXMLStreamWriter(result);
            }
            catch (XMLStreamException ex) {
                // ignore
            }
        }
        return streamWriter;
    }

That's the catch block that silently swallows my XmlStreamException.
And the exception is the same as in my previous posting: <Can not create a STaX writer for a SAXResult -- not (yet) implemented.>
--> see http://forum.springframework.org/showthread.php?t=26392


To get writing with XmlStreamWriter working i changed the createStreamWriter method of the inner class
ResponseCreatingStreamWriter within AbstractStaxStreamPayloadEndpoint to:

private void createStreamWriter() throws XMLStreamException {          
                // as a final resort, use a stream, and transform that at
                // endDocument()
                os = new ByteArrayOutputStream();
                streamWriter = getOutputFactory().createXMLStreamWriter(os);
            }
        }

and of course in the invokeInternal() of my endpoint class i added a writeEndDocument() at the end of reponse creation.
Now the response message is created properly. This is a workaround only,
to really fix it either the woodstox parser must implement Stax writing from SaxResult or the spring-ws code must be changed to return a StreamResult.

[Arjen Poutsma]

Ok i found a workaround for my problem...

From AbstractStaxStreamPayloadEndpoint:

private XMLStreamWriter getStreamWriter(Result result) {
        XMLStreamWriter streamWriter = null;
        if (result instanceof StaxResult) {
            StaxResult staxResult = (StaxResult) result;
            streamWriter = staxResult.getXMLStreamWriter();
        }
        if (streamWriter == null) {
            try {
                streamWriter = getOutputFactory().createXMLStreamWriter(result);
            }
            catch (XMLStreamException ex) {
                // ignore
            }
        }
        return streamWriter;
    }

That's the catch block that silently swallows my XmlStreamException.
And the exception is the same as in my previous posting: <Can not create a STaX writer for a SAXResult -- not (yet) implemented.>
--> see http://forum.springframework.org/showthread.php?t=26392

It silently catches the exception, because it is not a fatal error. If a XMLStreamWriter cannot be created from the payload source of the response, a byte array buffer is used in ResponseCreatingStreamWriter (os). Later, that byte array is transformed into the response payload when endDocument() is called.

I do admit that this solution was not very good: it basically required a endDocument() call. So I changed it: it now does the transforming process (if necessary) as part of ResponseCreateingStreamWriter.close(). That method is invoked by the AbstractStaxStreamPayloadEndpoint itself, so it is always called.

To get writing with XmlStreamWriter working i changed the createStreamWriter method of the inner class
ResponseCreatingStreamWriter within AbstractStaxStreamPayloadEndpoint to:

private void createStreamWriter() throws XMLStreamException {          
                // as a final resort, use a stream, and transform that at
                // endDocument()
                os = new ByteArrayOutputStream();
                streamWriter = getOutputFactory().createXMLStreamWriter(os);
            }
        }

and of course in the invokeInternal() of my endpoint class i added a writeEndDocument() at the end of reponse creation.
Now the response message is created properly. This is a workaround only,
to really fix it either the woodstox parser must implement Stax writing from SaxResult or the spring-ws code must be changed to return a StreamResult.

This workaround is basically the same as in the main codebase. Calling endDocument() is no longer a requirement, though.

Could you update your sources from Subversion, and see if the current code works for you? Thanks,