// file: $isip/class/java/AudioInterface/AudioInterface.java
// version: $Id: AudioInterface.java 10230 2005-09-13 14:29:30Z stanley $
//

// import necessary java libraries
//
import java.io.*;
import javax.sound.sampled.*;

/**
 * Presents a simple interface to read and write from a line.
 */
public class AudioInterface {
    
    //-------------------------------------------------------------------------
    //
    // public constants
    //
    //-------------------------------------------------------------------------
    
    /**
     * The constant for read mode
     */
    public static final int READ = 10;
    
    /**
     * The constant for write mode
     */
    public static final int WRITE = 20;
    
    //------------------------------------------------------------------------
    //
    // protected data
    //
    //-----------------------------------------------------------------------
    
    /**
     * This object is used to set the format of the audio data such as
     * the encoding, sample size, sample rate, number of channels,
     * byte order, frame rate and frame size
     */
    protected AudioFormat format_d;
    
    /**
     * Create an object of TargetDataLine to open and read the audio
     * data
     */
    protected TargetDataLine target_d;
    
    /**
     * Create an object of SourceDataLine to open and write the audio
     * data
     */
    protected SourceDataLine source_d;
    
    /**
     * Create a circular buffer object
     */
    protected AudioCircularBuffer cb_d; 
    
    /** 
     * The flag that is set when recording is taking place
     */
    protected static boolean recording_on = false;
    
    /**
     * The flag that is set when playback is taking place
     */
    protected static boolean stop_play_back = false;
    
    /**
     *  Gives the specific type of data representation used for an
     *  audio stream.
     */
    protected AudioFormat.Encoding encoding_d;
    
    /**  
     * The number of bits in each sample of a sound.
     */
    protected int sample_size_d;
    
    /**
     * The number of samples played or recorded per second
     */
    protected float sample_rate_d;
    
    /**
     * The number of audio channels
     */
    protected int num_channels_d;
    
    /**
     * Indicates whether the audio data is stored in big-endian or
     * little-endian order.
     */
    protected boolean big_endian_d;
    
    /**
     * The number of bytes in each frame
     */
    protected int frame_size_d;
    
    /**
     * The number of frames played or recorded per second
     */
    protected float frame_rate_d;
    
    /**
     * The number of bytes in each sample of a sound.
     */
    protected int sampleSizeInBytes;
    
    /**
     * The length of the buffer that should be read from the
     * dataline's buffer for each call
     */
    protected int buffer_length_to_read_d = 500;
    
    /**
     * The length of the buffer that should be written the dataline's
     * buffer.
     */
    protected int buffer_length_to_write_d = 500;

    /**
     * The buffer that contains the data to be played back
     */
    protected byte[] buf_playback; 
    
    /**
     * Set the mode to read or write.
     */
    protected int mode_d;

    //-------------------------------------------------------------------------
    //
    // public methods
    //
    //-------------------------------------------------------------------------
       
    /**
     * Constructor for the class.
     */
    public AudioInterface() {
	
	// initialize the circular buffer.
	//
	cb_d = new AudioCircularBuffer(AudioCircularBuffer.INFINITE_SIZE,
				       false);
	cb_d.clear();
    }
    
    //-------------------------------------------------------------------------
    //
    // class-specific public methods:
    //  set methods
    //
    //-------------------------------------------------------------------------
    
    /**
     * Sets the audio parameters for the format_d data field. It first
     * checks if the AudioFormat object passed as an argument is
     * supported by the line. If it is supported the format_d data field
     * is initialized with those audio parameters.
     *
     * @param format_a An AudioFormat object 
     *
     * @return a boolean value indicating status
     */
    public boolean setAudioFormat(AudioFormat format_a) {
	
	DataLine.Info info;
	
	// read mode.
	//
	if (mode_d == READ) {
	    
	    info = new DataLine.Info(TargetDataLine.class, format_a);
	    
	    // check if the format is supported.
	    //
	    if (!AudioSystem.isLineSupported(info)) {
		System.out.println("format not supported - setFormat");
		return false;
	    }	
	
	    // set the format 
	    //
	    this.format_d = new AudioFormat(format_a.getEncoding(), 
					    format_a.getSampleRate(), 
					    format_a.getSampleSizeInBits(), 
					    format_a.getChannels(),
					    format_a.getFrameSize(), 
					    format_a.getFrameRate(), 
					    format_a.isBigEndian());
	    
	    // set the values for all the individual parameters
	    //
	    encoding_d = format_d.getEncoding();
	    sample_rate_d = format_d.getSampleRate();
	    sample_size_d = format_d.getSampleSizeInBits();
	    num_channels_d = format_d.getChannels();
	    frame_size_d = format_d.getFrameSize();
	    frame_rate_d = format_d.getFrameRate();
	    big_endian_d = format_d.isBigEndian();
	    return true;
	}
	
	// write mode.
	//
	else if (mode_d == WRITE) {
	    
	    info = new DataLine.Info(SourceDataLine.class, format_a);
	    
	    // check if the format is supported.
	    //
	    if (!AudioSystem.isLineSupported(info)) {
		return false;
	    }   
	}
	
	// set the format 
	//
	this.format_d = new AudioFormat(format_a.getEncoding(), 
					format_a.getSampleRate(), 
					format_a.getSampleSizeInBits(), 
					format_a.getChannels(),
					format_a.getFrameSize(), 
					format_a.getFrameRate(), 
					format_a.isBigEndian());
	
	// set the values for all the individual parameters
	//
	encoding_d = format_d.getEncoding();
	sample_rate_d = format_d.getSampleRate();
	sample_size_d = format_d.getSampleSizeInBits();
	num_channels_d = format_d.getChannels();
	frame_size_d = format_d.getFrameSize();
	frame_rate_d = format_d.getFrameRate();
	big_endian_d = format_d.isBigEndian();
	return true;
    }
    
    /**
     * Set the encoding (PCM_SIGNED, PCM_UNSIGNED, ULAW,ALAW)
     *
     * @param encoding_a  a string object containing the encoding type
     *
     * @return  a boolean value indicating status
     */
    public boolean setEncoding(AudioFormat.Encoding encoding_a) {
	
	// create an AudioFormat.Encoding object with the user given
	// encoding type
	//
	encoding_d = encoding_a;
	return true;
    }
    
    /**
     * Set the sample size
     *
     * @param sample_size_a  an integer containing the sample size
     *
     * @return  a boolean value indicating status
     */
    public boolean setSampleSize(int sample_size_a) {
	
	// set the sample size
	//
	sample_size_d = sample_size_a;
	return true;
    }
    
    /**
     * Set the sample rate
     *
     * @param  sample_rate_a a float containing the sample rate
     *
     * @return  a boolean value indicating status
     */
    public boolean setSampleRate(float sample_rate_a) {
	
	// set the sample rate
	//
	sample_rate_d = sample_rate_a;
	return true;
    }
    
    /**
     * Set the number of channels
     *
     * @param num_channels_a an integer containing the number of
     * channels
     *
     * @return a boolean value indicating status
     */
    public boolean setNumChannels(int num_channels_a) {
	
	// set the number of channels
	// 
	num_channels_d = num_channels_a;
	return true;
    }
    
    /**
     * Set the byte order (BigEndian , LittleEndian)
     *
     * @param big_endian_a a boolean value indicating if it is a big
     * endian
     *
     * @return a boolean value indicating status
     */    
    public boolean setBigEndian(boolean big_endian_a) {
       	
	// set the byte order
	//
	big_endian_d = big_endian_a;
	return true;
    }
    
    /**
     * Set the frame size
     *
     * @param  frame_size_a an integer containing the frame size
     *
     * @return a boolean value indicating status
     */
    public boolean setFrameSize(int frame_size_a) {
	
	// set the frame size
	//
	frame_size_d = frame_size_a;
	return true;
    }
    
    /**
     * Set the frame rate
     *
     * @param frame_rate_a an integer containing the frame rate
     *
     * @return a boolean value indicating status
     */    
    public boolean setFrameRate(float frame_rate_a) {
	
	// set the frame rate
	//
	frame_rate_d = frame_rate_a;
	return true;
    }
    
    /**
     * Set the mode
     *
     * @param mode_a an integer value indicating the mode
     *
     * @return a boolean value indicating status
     */    
    public boolean setMode (int mode_a) {
	
	// set the mode
	//
	mode_d = mode_a;
	return true;
    }


    /**
     * Extract the audio parameters from ConfigData object
     *
     * @param data_a a ConfigData object
     *
     * @return a boolean value indicating status
     */    
    public boolean setAudioConfig(ConfigData data_a) {
     
	
	// loop all values
	//
	for (int i = 0; i < data_a.getAssociation().size(); i++) {
	    
	    // set the sample rate
	    //
	    if (data_a.getName().get(i).equals("SampleRate")) {
		
		setSampleRate(Float.parseFloat((String)(data_a.getValue().get(i))));
		setFrameRate(Float.parseFloat((String)(data_a.getValue().get(i))));
	    }
	    
	    // set the sample size
	    //
	    else if (data_a.getName().get(i).equals("SampleSize")) {
		
		setSampleSize((int)(Float.parseFloat((String)(data_a.getValue().get(i)))));
	    }
	    
	    // set the encoding
	    //
	    else if (data_a.getName().get(i).equals("Encoding")) {
		
		String encoding	=(String)(data_a.getValue().get(i));
		
		// try to the user set format(which is a string) and
		// try to set the corresponding AudioFormat.Encoding
		// object
		//
		if(encoding == "PCM_SIGNED") {
		    setEncoding(AudioFormat.Encoding.PCM_SIGNED);
		}
		else if (encoding == "PCM_UNSIGNED") {
		    setEncoding(AudioFormat.Encoding.PCM_UNSIGNED);
		}
		else if (encoding == "ULAW") {
		    setEncoding(AudioFormat.Encoding.ULAW);
		}
		else if (encoding == "ALAW") {
		    setEncoding(AudioFormat.Encoding.ALAW);
		}
	    }
	    
	    // set the number of channels
	    //
	    else if (data_a.getName().get(i).equals("NumChannels")) {
		
		setNumChannels((int)(Float.parseFloat((String)(data_a.getValue().get(i)))));
	    }
	    
	    // set the byte order
	    //
	    else if (data_a.getName().get(i).equals("ByteOrder")) {
		
		String byteorder = (String)(data_a.getValue().get(i));
		
		// get the user set byte order (which is a string) and
		// set the correspoding boolean value
		//
		if (byteorder == "BigEndian") {
		    setBigEndian(true);
		}
		else if (byteorder == "LittleEndian") {
		    setBigEndian(false);
		}
	    }
	} 
	setFrameSize((int)((sample_size_d/8)*num_channels_d));
	
	// using the individual audio parameters set the AudioFormat
	// object
	//
	format_d =  new AudioFormat(encoding_d, sample_rate_d, sample_size_d, 
				    num_channels_d, frame_size_d, frame_rate_d, 
				    big_endian_d); 
	return true;	
    }
       

    //-------------------------------------------------------------------------
    //
    // class-specific public methods:
    //  get methods
    //
    //-------------------------------------------------------------------------
    
    /**
     * Get the audioformat. This method returns a AudioFormat object
     * with the same audio parameters as that of format_d
     *
     * @return AudioFormat object
     */
    public AudioFormat getAudioFormat() {
	return new AudioFormat(format_d.getEncoding(), 
			       format_d.getSampleRate(), 
			       format_d.getSampleSizeInBits(), 
			       format_d.getChannels(),
			       format_d.getFrameSize(), 
			       format_d.getFrameRate(), 
			       format_d.isBigEndian());
    } 
    
    /**
     * Get the encoding
     *
     * @return a AudioFormat.Encoding object
     */    
    public AudioFormat.Encoding getEncoding() {
	return format_d.getEncoding();
    }
    
    /**
     * Get the sample size
     *
     * @return an int value containing the sample size
     */    
    public int getSampleSize() {
	return format_d.getSampleSizeInBits();
    }
    
    /**
     * Get the sample rate
     *
     * @return a float value containing the sample rate
     */    
    public float getSampleRate() {
	return format_d.getSampleRate();
    }
    
    /**
     * Get the number of channels
     *
     * @return an int value containing the number of channels
     */    
    public int getNumOfChannels() {
	return format_d.getChannels();
    }
    
    /**
     * Get the flag to indicate if it is big endian
     *
     * @return a boolean value to indicate whether it is big endian
     */    
    public boolean getBigEndian() {
	return big_endian_d;
    }
    
    /**
     * Get the frame size
     *
     * @return  an int value containing the frame size
     */    
    public int getFrameSize() {
	return format_d.getFrameSize();
    }
    
    /**
     * Get the frame rate
     *
     * @return  a int value containing the frame rate
     */    
    public float getFrameRate() {
	return format_d.getFrameRate();
    }
    
     /**
     * Get the mode
     *
     * @return a int value indicating the mode
     */    
    public int getMode() {
	return mode_d;
    }
    
    
    //-------------------------------------------------------------------------
    //
    // class-specific other public methods:
    //  
    //
    //-------------------------------------------------------------------------
    
    /**
     * If it is read mode, it creates an audioformat object with the
     * audio parameters the user has set. It checks if the format is
     * supported. If supported it creates a TargetDataLine object and
     * opens the line. If it is write mode, it does the same things
     * that it does in read mode except that it creates an
     * SourceDataLine object and opens it for writing.
     *
     * @return a boolean value
     */
    public boolean open() {
	
	// if it is read mode, use a TargetDataLine object
	//
	if (mode_d == READ) {
	    
	    // create an AudioFormat object with the user specified
	    // audio parameters
	    //
	    System.out.println("the num of channels" + num_channels_d);
	    format_d = new AudioFormat (encoding_d,sample_rate_d,
					sample_size_d,
					num_channels_d,
					frame_size_d,
					frame_rate_d,
					big_endian_d);
	    System.out.println("The format that has been set" +format_d);
	    
	    
	    // constructs a Info object from the specified information
	    // using the AudioFormat object
	    //
	    DataLine.Info info = new DataLine.Info(TargetDataLine.class, 
						   format_d);
	    if(!AudioSystem.isLineSupported(info)) {
		System.out.println("Format not supported");
		return false;
	    }
	    
	    try {
		
		// obtains a line that matches the description in the
		// specified DataLine.Info object
		//
		target_d = (TargetDataLine)AudioSystem.getLine(info);
		
		// open the line for reading
		//
		target_d.open(format_d);
	    }
	    catch (Exception e) {
		errorHandler(e);
	    }	
	}
	
	// if it is write mode, use a SourceDataLine object
	//
	else if (mode_d == WRITE) {
	    
	    // create an AudioFormat object with the user specified
	    // audio parameters
	    //
	    format_d = new AudioFormat(encoding_d,sample_rate_d,
				       sample_size_d,
				       num_channels_d,
				       frame_size_d,
				       frame_rate_d,
				       big_endian_d);

	    // constructs a data Info object from the specified
	    // information using the AudioFormat object
	    //
	    DataLine.Info info =new DataLine.Info(SourceDataLine.class, 
						  format_d);	  
	    
	    // check if the line is supported
	    //
	    if(!AudioSystem.isLineSupported(info)) {
		return false;
	    }
	    
	    try {	
		
		// obtains a line that matches the description in the
		// specified DataLine.Info object
		//
		source_d =(SourceDataLine)AudioSystem.getLine(info);
		
		// open the line for writing
		//
		source_d.open(format_d);
	    }
	    
	    catch (Exception e) {
		errorHandler(e);
	    }		
	}
	return true;   
    }
    
    /**
     * Allows a line to engage in data I/O. If invoked on a line that
     * is already running, this method does nothing. Unless the data
     * in the buffer has been flushed, the line resumes I/O starting
     * with the first frame that was unprocessed at the time the line
     * was stopped. for read mode this also starts a record thread
     * which constantly reads the thread and puts it in a circular
     * buffer.
     *
     * @return a boolean value indicating status
     */
    public boolean start() {
	
	// read mode.
	//
	if (mode_d == READ) {
	    target_d.start();
	}
	
	// write mode.
	//
	else if (mode_d == WRITE) {
	    source_d.start();
	}	
	return true;
    }
    
    
    /**
     * Stops the line. A stopped line should cease I/O activity. If the
     * line is open and running, however, it should retain the resources
     * required to resume activity. A stopped line should retain any
     * audio data in its buffer instead of discarding it, so that upon
     * resumption the I/O can continue where it left off, if
     * possible. In read mode, it sets the recording_on flag to false
     * which stops the record thread from running. In the write mode,
     * the stop_play_back flag is set to true so that the playback
     * thread stops running.
     *
     * @return a boolean value indicating status
     */
    public boolean stop() {
	
	// read mode.
	//
	if (mode_d == READ) {
	    
	    // stop the I/O activity
	    //
	    target_d.stop();
	}
	
	// write mode.
	//
	else if (mode_d == WRITE) {
	    
	    // stop the I/O activity
	    //
	    source_d.stop();
	    stop_play_back = false;
	}
	return true;
    }
    
    /**
     * Closes the line, indicating that any system resources in use by
     * the line can be released.
     *
     * @return a boolean value indicating status
     */
    public boolean close() {
	
	// read mode.
	//
	if (mode_d == READ) {
	    target_d.close();
	    System.out.println("The line has been closed.");
	}
	
	// write mode.
	//
	else if (mode_d == WRITE) {
	    source_d.close();
	    System.out.println("closing the line opened for playback.");
	}
	return true;
    }    
    
    /**
     * Read the audio data from the circular buffer and then creates a
     * AudioSignal object ans returns the object to the calling
     * program. If the audio data in the circular buffer is less than
     * the requested number of samples the function returns what ever is
     * in the circular buffer. If the circular buffer has more data than
     * the requested then the requested number of samples is returned.
     *
     * @param sample_size_a number of samples that should be read. 
     * @param signal_a the object which will contain the audio data.
     *
     * @return an int value indicating the number of float values read
     * into the signal. If circular buffer is empty and producer has
     * stopped writing to the circular buffer it returns -1.
     */
    public int read (AudioSignal signal_a ,int sample_size_a) {
	
	int num_channels = getNumOfChannels();
	
	// calculate the sample size in Bytes
	//
	sampleSizeInBytes = (format_d.getSampleSizeInBits()/8);
	int availSamples = (int)(cb_d.getNumElements()/sampleSizeInBytes);
	float[][] fbuf ; 
	
	
        if (availSamples == 0 && cb_d.isDone()) {
	    return -1;
	}
	else if (availSamples == 0) {
	    return 0;
	}
	
	// check whether the available samples in the circular buffer
	// is less than the requested samples
	//
	else if (availSamples < sample_size_a ) {
	    Object [] buffer = new Object[availSamples*sampleSizeInBytes];
	    try {
		
		// read the available samples from the circular buffer
		//
		cb_d.read(buffer,0,availSamples*sampleSizeInBytes);
	    }
	    catch (Exception e) {
		errorHandler(e);
	    }
	    
	    byte [] buf = new byte[availSamples*sampleSizeInBytes];
	    fbuf = new float [num_channels][availSamples/num_channels];
	    
	    // the loop below converts java's Object array into a byte
	    // array so that is can be written to an AudioSignal
	    // object
	    //
	    for(int i=0;i<buffer.length;i++) {
		Byte temp = (Byte) buffer[i];
		buf[i] =  temp.byteValue();
	    }
	    
	    System.out.println("The buffer length" +buf.length);
	    
	    // convert the byte array which we created into a float
	    // array so that we can write it to a AudioSignal object
	    //
	    byteToFloat(fbuf,buf,availSamples);
	    
	    // set the data and the format to the AudioSignal object
	    //
	    signal_a.setFormat(format_d);
	    signal_a.setData(fbuf);
	    return (int) fbuf[0].length;
	}
	
	// check if the available samples in the circular buffer is
	// more than or equal to the requested samples
	//
	else if (availSamples >= sample_size_a) {
	    Object [] buffer = new Object[sample_size_a*sampleSizeInBytes];
	    try {
		
		// read the requested number of samples from the
		// circular buffer
		//
		cb_d.read(buffer,0,sample_size_a*sampleSizeInBytes);
	    }
	    catch (Exception e) {
		errorHandler(e);
	    }
	    byte [] buf = new byte [ sample_size_a*sampleSizeInBytes];
	    fbuf = new float [num_channels] [sample_size_a/num_channels];
	    
	    // the loop below converts java's Object array into a byte
	    // array so that is can be written to an AudioSignal
	    // object
	    //
	    for(int i=0;i<buffer.length;i++) {
		
		Byte temp = (Byte) buffer[i];
		buf[i] =  temp.byteValue();	
	    }
	    
	    // convert the byte array which we created into a float
	    // array so that we can write it to a AudioSignal object
	    //
	    byteToFloat(fbuf,buf,sample_size_a);
	    
	    // set the data and the format to the AudioSignal object
	    //
	    signal_a.setFormat(format_d);
	    signal_a.setData(fbuf);
	    return (int) fbuf[0].length;
	}
	
	return 0;
    }
    
    /**
     * Get the AudioSignal object from the calling program and get the
     * data into an audioInputStream object and then start the playback
     * thread that writes the audio data to be played to the line.
     *
     * @param signal_a the AudioSignal object having the data to be
     * played back
     *
     * @return a boolean value indicating status
     */
    public boolean startPlayBack (AudioSignal signal_a) {
	
	// get the audio data from the AudioSignal object
	//
	float [][] buff = signal_a.getData();
	int length = buff[0].length;
	buf_playback = new byte [buff[0].length*(sampleSizeInBytes)*getNumOfChannels()]; 
	
	// convert the float array into a byte array so that it can be
	// loaded into an AudioInputStream object
	//
	floatToByte(buf_playback,buff);  
	
	// the playback thread and start it
	//
	PlayThread playThread = new PlayThread();
	playThread.setPriority(5);
	System.out.println("The play thread has been started");
	playThread.start();
	return true;
    }
    
    /**
     * Sets the stop_play_back flag to true and hence stopping the
     * playbackthread from running.
     *
     * @return boolean
     */
    public boolean stopPlayBack () {
	
	// set the stop_play_back flag to true
	//
	stop_play_back = true;
	return true;
    }
    
    /**
     * Set the recording_on flag to true and start the recording
     * thread.
     *
     * @return a boolean value indicating status
     */
    public boolean startRecording() {
	
	// set the recording_on flag to true
	//
	recording_on = true;
	
	// create a record thread and start the thread.
	//
	RecordThread recordThread = new RecordThread();
	recordThread.start();
	return true;
    }
    
    /**
     * Set the recording_on flag to false so that the recording thread
     * stops running
     *
     * @return a boolean value indicating status
     */
    public boolean stopRecording() {
	
	// setting the flag to false makes the record thread to cease
	// running
	//
	recording_on = false;
	cb_d.done();
	return true;
    }

    //------------------------------------------------------------------------
    //
    // class-specific public methods:
    //  error handler code
    //
    //------------------------------------------------------------------------

    /**
     * Does the error handling whenever an exception gets thrown. It
     * prints the exception and also prints the trace of methods from
     * where the error originated.
     *
     * @param e An object of exception class
     *
     * @return a boolean value indicating status
     */    
    public boolean errorHandler(Exception e) {
	
	// print the Exception that occured
	//
	System.out.println("Exception in AudioInterface: " + e);
	
	// print the the trace of methods from where the error originated
	//
	e.printStackTrace();

	// exit gracefully
	//
	return true;
    }
        
    //-----------------------------------------------------------------------
    //
    // debug method for this class
    //
    //-----------------------------------------------------------------------

    /**
     * A method used to print out debug information for this class
     *
     * @return String to represent this object
     */
    public String toString() {
	
	// define a string
	//
	String result ="The audio parameters:\n";
	
	// display the encoding type
	//
	result += "Encoding type: " + encoding_d  + "\n";
	
	// display the sample rate 
	//
	result += "Sample Rate: " + sample_rate_d + "\n";
	
	// display the sample size in bits
	//
	result += "Sample Size: " + sample_size_d + "\n";

	// display the number of channels 
	// 
	result += "Number of channels: " + num_channels_d + "\n";

	// display the frame size
	//
	result += "Frame Size: " + frame_size_d + "\n";

	// display the frame rate
	//
	result += "Frame Rate: " + frame_rate_d + "\n" ;
	
	// display the byte order
	//
	result += "Byte Order: " + big_endian_d + "\n";

	// display the current mode
	//
	if (mode_d == READ) {
	    result += "The current mode: READ";
	}
	else {
	    result += "The current mode: WRITE";
	}
	
	result += "\n";
	
	return result;
    }
        
    //-------------------------------------------------------------------------
    //
    // inner classes for this class
    //  
    //
    //-------------------------------------------------------------------------
       
    /**
     * An inner class that has the run method for the recording thread
     */  
    class RecordThread extends Thread {
	
	// a byte object
	//
	byte[] data = new byte[buffer_length_to_read_d];
	Object [] buf_write = new Object[buffer_length_to_read_d];
	int numRead;
	
	// this should be removed
	// 
	int count = 0;
	
	public void run() {
	    
	    try {
		
		// while recording is still taking place 
		//
		while (recording_on == true) { 
		    
		    // read the "buffer_length_to_write_d" of audio
		    // data in the byte array.
		    //
		    numRead = target_d.read(data, 0, buffer_length_to_read_d);
		    count += buffer_length_to_read_d;
		    
		    // convert the byte array into an java's Object
		    // array so that it can be return to the circular
		    // buffer
		    //
		    for ( int i =0; i < buffer_length_to_read_d; i++) {
			Byte temp = new Byte(data[i]);
			buf_write[i] = temp;
		    }
		    
		    // write the object buffer to a circular buffer
		    //
		    cb_d.write(buf_write); 
		}
	    }
	    
	    catch (Exception e) {
		errorHandler(e);
	    }
	}
    }
    
 

    /**
     * An inner class that has the run method of the playback thread.
     */  
    class PlayThread extends Thread {
	
	byte tempBuffer[] = new byte[buffer_length_to_write_d];
	
	// create an AudioInputStream object and load the buffer to be
	// played back
	//
	AudioInputStream audioInputStream = getAudioInputStream (buf_playback); 
	int length_playback = buf_playback.length;

	public void run(){
	    try {
		int cnt;	

		// keep looping until the input read method
		// returns -1 for empty stream or the user clicks
		// the Stop button causing stopPlayback to switch
		// from false to true.
		//
		while ((cnt = audioInputStream.read( tempBuffer,0,
						    tempBuffer.length)) != -1 && stop_play_back == false) {
		    if (cnt > 0) {

			// write data to the internal buffer of
			// the data line where it will be
			// delivered to the speaker.
			//
			source_d.write(tempBuffer, 0, cnt);
			}
		}
			stop_play_back = false;
	    }
	    catch (Exception e) {
		errorHandler(e);
	    }
	}
    }
    
  
    //-------------------------------------------------------------------------
    //
    // class-specific other private methods:
    //  
    //
    //-------------------------------------------------------------------------

    /** 
     * Convert float array to byte array.
     *
     * @param byteSound User provided byte array to return result in.
     * @param dbuf User provided float array to convert.
     */
    private void floatToByte(byte[] byteSound, float [][] dbuf) {
        
	// check whether this will work
	//
	int bufsz = dbuf[0].length;
        int ib = 0;
        if(format_d.isBigEndian()) {
            for(int i = 0; i < bufsz; i++) {
                int j=0;
		while (j < getNumOfChannels()) {
		    short y = (short)Math.round(32767 * dbuf[j][i]);
		    byteSound[ib] = (byte)(y >> 8);
		    ib++;
		    byteSound[ib] = (byte)(y & 0x00ff);
		    ib++;
		    j++;
		}
	    }
        } 
	else {
            for(int i=0;i<bufsz;i++) {
                int j=0;
		while(j < getNumOfChannels()) {
		    short y = (short)Math.round(32767 * dbuf[j][i]);
		    byteSound[ib] = (byte)(y & 0x00ff);
		    ib++;
		    byteSound[ib] = (byte)(y >> 8);
		    ib++;
		    j++;
		}
	    }
        }
    }
    
    /** 
     * Convert byte array to float array.
     *
     * @param dbuf User provided float array to return result in.
     * @param dbuf User provided byte array to convert.
     * @param bufsz Number of float samples to write.
     */
    private void byteToFloat(float [][] dbuf, byte[] bbuf, int bufsz) {
        
	int num_channels = getNumOfChannels();
	int ib = 0;
	int j;
	if(format_d.isBigEndian()) {
            for(int i = 0; i < (bufsz/num_channels); i++) {
		j = 0;
		while (j < num_channels) {
		    short y = bbuf[ib];
                y = (short)(y << 8);
                y |= (bbuf[ib+1]&0x00ff);
                ib += 2;
                dbuf[j][i] = y / 32767.f;
		j++;
		}
	    }
        } 
	else {
            for(int i = 0; i < (bufsz/num_channels); i++) {
		j = 0;
		while (j < num_channels) {
		    short y = (short)bbuf[ib+1];
		    y = (short)(y << 8);
		    y |= (bbuf[ib]&0x00ff);
		    ib += 2;
		    dbuf[j][i] = y / 32767.f;
		    j++;
		}
	    }
	}
    }
    
    
    /** 
     * Load the byte array into a AudioInputStream object
     *
     * @param audio_data_a the byte array that needs to be played back
     *
     * @return AudioInputStream an AudioInputStream object containing
     * the byte array
     */
    private AudioInputStream getAudioInputStream(byte[] audio_data_a){
	
	ByteArrayInputStream bais = new ByteArrayInputStream(audio_data_a);
	return new AudioInputStream(bais, 
				    format_d, 
				    (audio_data_a.length));
    }
    
    //-------------------------------------------------------------------------
    //
    // main diagnostic method for this class
    //
    //-------------------------------------------------------------------------
    
    /**
     * Diagnostic method for this class
     *
     * @param args arguments from the command line
     */
     public static void main (String[] args) {

	 // create an AudioInterface object
	 //
	 AudioInterface audioInterface = new AudioInterface();
	 
	 // a default format that can be used by the test program
	 //
	 AudioFormat SPEECH = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED, 
					      16000.0F, 
					     16, 1, 2, 16000.0F, false);
	 
	 // set the mode to READ
	 //
	 audioInterface.mode_d = audioInterface.READ;
	 
	 // check if the format is supported
	 //
	 if(!audioInterface.setAudioFormat(SPEECH)) {
	     System.out.println("format not supported - main");
	 }
	 
	 // create an TargetDataLine object and open the line
	 //
	 audioInterface.open();
	 
	 // start the line
	 //
	 audioInterface.start();
	 
	 // start the recording thread and keep writing the audio data
	 // into the circular buffer
	 //
	 audioInterface.startRecording();
	 
	 // Sleep for sometime to allow the recording to take place
	 //
	 try {
	     Thread.sleep(5500);
	 }
	 catch (Exception e) { }
	 
	 // stop the recording thread
	 //
	 audioInterface.stopRecording();
	 
	 // stop the line
	 //
	 audioInterface.stop();
	 
	 // close the line
	 //
	 audioInterface.close();
	 
	 // create an AudioSignal object
	 // 
	 AudioSignal signal = new AudioSignal();
	 
	 // read the data from an circular buffer into a AudioSignal
	 // object
	 //
	 if(audioInterface.read(signal,79000)== -1) {
	     System.out.println("There is a problem with read");
	 }
	 
	 // get the data from the AudioSignal object
	 //
	 float [][] audio =signal.getData();
	 
	 // switch to write mode
	 //
	 audioInterface.mode_d = audioInterface.WRITE;
	 if(!(audioInterface.setAudioFormat(SPEECH))){
	     System.out.println("format not supported");
	 }
	 
	 // create an SourceDataLine object and open the line
	 //
	 audioInterface.open();
	 
	 // start the line
	 //
	 audioInterface.start();
	 
	 // write the signal object to the line
	 //
	 audioInterface.startPlayBack(signal);
	 
	 // sleep for sometime so that playback takes place
	 // 
	 try {
	     Thread.sleep(5000);
	 }
	 catch (Exception e) { }
	 
	 // stop the line
	 //
	 audioInterface.stop();
	 
	 // close the line
	 //
	 audioInterface.close();
     }
}