Java流的奇怪行为

Question

I've the necessity to share a streaming of data between two instances as below:

// get EClasses which should be connected
    final uk.man.xman.xcore.Parameter source = getParameter(sourceAnchor);
    final uk.man.xman.xcore.Parameter target = getParameter(targetAnchor);

    // Set data channels

    //Output stream
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    DataOutputStream dataOutputStream = new DataOutputStream(new BufferedOutputStream(outputStream));
    source.setOutputStream(dataOutputStream);

    //Input stream
    DataInputStream inpuDataStream = new DataInputStream(new BufferedInputStream(new ByteArrayInputStream(outputStream.toByteArray())));
    target.setInputStream(inpuDataStream);

Everything works ok if I write, during those lines of code. Strangely, when I need to use the data channel to write something in another class, like here:

    DataOutputStream dataOutputStream = (DataOutputStream) inputParameter.getOutputStream();
            System.out.println("WRITE:" + attributes.getValue("value"));
            dataOutputStream.writeUTF(attributes.getValue("value"));
            dataOutputStream.flush();

I am not able to read, and I really do not know why. Am I missing something?

Thanks for your time

Answer 1

Not sure if that's what you're asking, but you're creating an InputStream that reads from an empty byte array. That doesn't make much sense:

// create an Output stream that will write in memory
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
...

// transform what has been written to the output stream into a byte array. 
// Since othing has been written yet, outputStream.toByteArray() returns 
// an empty array
DataInputStream inpuDataStream = new DataInputStream(new BufferedInputStream(new ByteArrayInputStream(outputStream.toByteArray())));