XmlBeans and the problem with Socket.getOutputStream()

[Gordon Beaton]

I am using XmlBeans v2 for a project where I need to send an xml
file through the network. I have a server that waits for incoming
requests, and a client that builds the xml, sends it to the server,
and then it waits for the response xml.
[...]

Now, the problem that I'm having is on the server. The parse()
method doesn't stop reading data from inputStream after the xml was
completely sent to it. So it keeps waiting for data, even if the
object on the client has finished sending data.
[...]

This problem is really nasty to me, since I want to be able to send
more data on the outputstream, from the client, after the xml was
sent. So, to close the outputstream after the xml was sent, it
doesn't really help me (and, moreover, if I close the outputstream,
I get a new exception when I try to close the socket or when I try
to read from the InputStream, which I think is natural).

It sounds to me like you have conflicting requirements. If parse()
needs to read to EOF, then your client needs to close the OutputStream
or at least call socket.shutdownOutput() before that can occur. On the
other hand if you need to send more data on the *same* stream, then
EOF is the wrong condition for parse() to be waiting for.

An alternative is to have the client open a new connection for each
request, and use socket.shutdownOutput() to signal EOF before reading
the response.

Another is to have the server read from the incoming stream to
intermediate storage, then create (for example) a
ByteArrayInputStream() that you can pass to parse().

/gordon

 

[bogdan.mocanu]

Hello,

I am using XmlBeans v2 for a project where I need to send an xml file
through the network. I have a server that waits for incoming requests,
and a
client that builds the xml, sends it to the server, and then it waits
for the
response xml.

So I'm using on the client something like this :

//______________________________________________________________________
MyXmlDoc xmlDoc = MyXmlDoc.Factory.newInstance();
// here I create & populate the xml with data

Socket socket = new Socket( host, port );
xmlDoc.save( socket.getOutputStream() );

MyResponseXmlDoc responseDoc = MyResponseXmlDoc.Factory.parse(
socket.getInputStream() );


And on the server :


//______________________________________________________________________
ServerSocket serverSocket = new ServerSocket( port );
Socket clientSocket = socket.accept();

MyXmlDoc xmlDoc = MyXmlDoc.Factory.parse( clientSocket.getInputStream()
);
// process the request xml

MyResponseXmlDoc responseDoc = MyResponseXmlDoc.Factory.newInstance();
// create the response xml

responseDoc.save( clientSocket.getOutputStream() );


Now, the problem that I'm having is on the server. The parse() method
doesn't stop reading
data from inputStream after the xml was completely sent to it. So it
keeps waiting for data, even if the object on the client has finished
sending data.

I tried sending, to the server, a '\0' character, after the call to

xmlDoc.save( socket.getOutputStream() );
hoping that maybe this way I could signal an end of file to the reader
on the server. But it worked only partially, because the reader indeed
finished reading file, but then the xml parser cried out, saying that
0x0 character was not part of the xml file.

I mention that I also tried to flush() the streams, after sending the
xmls, but this was again a useless action.

This problem is really nasty to me, since I want to be able to send
more data on the outputstream, from the client, after the xml was sent.
So, to close the outputstream after the xml was sent, it doesn't
really help me (and, moreover, if I close the outputstream, I get a new
exception when I try to close the socket or when I try to read from the
InputStream, which I think is natural).

I hope the provided information regarding my problem is enough.

Best regards,
Bogdan.

 

[bogdan.mocanu]

Thanks Gordon for you quick answer.

Yes indeed, the only option that I can think of now is the third
approach (create a secondary stream, read data to it and
then pass this stream to XmlBeans).

What I find strange about this is that my problem is not a very
complicated one, and I thought there is another way to solve it,
something related to XmlBeans. I mean it is natural to think that
an xml created with XmlBeans should be easily sent through the
network and the parsed at the other end of the cable.

Anyway, thanks for the answer.