/**

 * Serializes objects and data to a stream, which can also be

 * transformed. The product of the process is written to a file.

 *

 * @param source          object to serialize or transform

 * @param filename        filename of the target document,

 *                        including path and extension

 * @param transformation  type of transformation to perform;

 *                        indicates which transformation script to use.

 *                        When <code>null</code>, no transformation

 *                        is performed, only serialization.

 *

 * @return <code>true</code> when the process succeeds.

 */

public static boolean transformObject(Object source, String filename, String transformation) {

    boolean success = false;

    try {

        // Create a stream to the output file.

        NSXMLOutputStream stream = (NSXMLOutputStream)openStream(filename, false, transformation);// 1

        // Serialize data to XML output stream.

        stream.writeObject(source);

        stream.flush();

        closeStream(filename);

        success = true;

    }

    catch (IOException e) {

        e.printStackTrace();

    }

    return success;

}

/**

 * Opens a file stream to or from a file and a corresponding

 * output or input object stream.

 * Adds the pair of streams to an internal dictionary for use by

 * the <code>closeStream</code> method.

 *

 * @param filename         fully qualified filename of the

 *                         target or source file; identifies

 *                         the channel to open

 * @param input_stream     indicates whether the stream returned

 *                         is an input stream or an output stream:

 *                         <code>true</code> for an input stream and

 *                        <code>false</code> for an output stream.

 * @param transformation  type of transformation to perform;

 *                        indicates which transformation script to use.

 *                        When <code>null</code>, no transformation

 *                        is performed, only serialization.

 *

 * @return object stream, <code>null</code> when the stream

 *         could not be created.

 */

private static Object openStream(String filename, boolean input_stream, String transformation) throws IOException {

    BufferedOutputStream file_output_stream = null;

    BufferedInputStream file_input_stream = null;

    Channel channel;

    Object xml_stream = null;

    if (input_stream) {

        // Create an input stream from the file.

        file_input_stream = new BufferedInputStream(new FileInputStream(filename));

        // Create object input stream.

        xml_stream = new NSXMLInputStream(file_input_stream);

        channel = new Channel(file_input_stream, xml_stream, input_stream);

    } else {

        // Create an output stream to the file.

        file_output_stream = new BufferedOutputStream(new FileOutputStream(filename));

        // Create object output stream.

        if (transformation != null) {

            xml_stream = initializeTransformer(file_output_stream, transformation);// 1

        } else {

            xml_stream = new NSXMLOutputStream(file_output_stream);

        }

        // Set the format of the output document (XML).

        NSXMLOutputFormat format = new NSXMLOutputFormat(true);// 2

        ((NSXMLOutputStream)xml_stream).setOutputFormat(format);// 3

        channel = new Channel(file_output_stream, xml_stream, input_stream);

    }

    channels.setObjectForKey(channel, filename);

    return xml_stream;

}

/**

 * Initializes the transformer.

 *

 * @param file_stream       target file stream

 * @param transformation    type of transformation to perform;

 *                          indicates which transformation file to use

 *

 * @throws IOException when there's a problem initializing the transformer.

 */

private static NSXMLOutputStream initializeTransformer(BufferedOutputStream file_stream, String transformation) throws IOException {

    NSXMLOutputStream xml_stream = new NSXMLOutputStream(file_stream, new File(transformationURI(transformation)));// 1

    Transformer transformer = ((NSXMLOutputStream)xml_stream).transformer();

    transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");

    return xml_stream;

}