Question

I am developing simple producer-consumer example. One thread records audio samples using AudioRecord class and writes them into buffer. Second one just reads the buffer and does nothing. When user wants to stop recording first thread writes special characters into the buffer and its a indicator for the other that reading is over. Here is my code

public class SpellCollectorActivity extends Activity implements OnClickListener{
  private ArrayBlockingQueue<byte[] > audioq;
  boolean needToBeStopped = false; 
  Button generate, action;

  private MyRecorder  rec;
  private MyReader mr;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    action = (Button) findViewById(R.id.actionButton);
    action.setOnClickListener(this);

    needToBeStopped = false;
    audioq = new ArrayBlockingQueue<byte[]>(CAPACITY);
}

public void onClick(View arg0){
    switch(arg0.getId()){
    case R.id.generateButton:
        generateContentToSpell();
        break;
    case R.id.actionButton:
        if(needToBeStopped){
            rec.stopThread();
            needToBeStopped = false;
            action.setText(this.getString(R.string.start));
        }else{
            rec = new MyRecorder(audioq);
            mr = new MyReader(audioq);
            rec.start();
            mr.start();
            needToBeStopped = true;
            action.setText(this.getString(R.string.stop));
        }
        break;
    }
}

  private class MyRecorder extends Thread{  
    private static final int freq = 22050;
    private static final int  channelConfiguration =    AudioFormat.CHANNEL_CONFIGURATION_MONO;
    private static final int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;

    private final BlockingQueue<byte[] > myRecAudioq;
    private AudioRecord recorder;
    private boolean recording = false;
    int bufferSize;

    /*konstruktor*/
    public MyRecorder(BlockingQueue<byte[]> q ){
        bufferSize =  AudioRecord.getMinBufferSize(freq, channelConfiguration, audioEncoding);
        myRecAudioq = q;
    }

    public void run(){
        recorder = new AudioRecord(MediaRecorder.AudioSource.MIC, 
                   freq, channelConfiguration, 
                   audioEncoding, 3*bufferSize);
        recorder.startRecording();
        recording = true;
        byte[] buffer = new byte[bufferSize];
        while(recording){
            int readBufferSize = recorder.read(buffer, 0, bufferSize);
            if(readBufferSize>0){
                try {
                    myRecAudioq.put(buffer);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }

    public void stopThread(){
        recorder.stop();
        recording = false;
        byte[] buffer = new byte[bufferSize];
        for(int i=0;i<bufferSize;i++){
            buffer[i] =(byte) 0xff;
        }
        try {
            myRecAudioq.put(buffer);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

   private class MyReader extends Thread{
    private final BlockingQueue<byte[]> bq;

    private static final int freq = 22050;
    private static final int  channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
    private static final int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;

    private int counter = 0;

    public MyReader(BlockingQueue<byte[]> q){
        bq = q;
    }
    public void run(){
        int buffSize =  AudioRecord.getMinBufferSize(freq, channelConfiguration, audioEncoding);
        byte[] compareBuffer= new byte[buffSize];
        for(int i=0;i<buffSize;i++){
            compareBuffer[i] = (byte)0xff;
        }

        boolean reading = true;
        byte[] buffer = null;
        do{
            try {
                buffer = bq.take();
   reading = buffer.equals(compareBuffer);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            if(reading){
                int c=1;
            }
        }while(!reading);
        int a=5;
    }
  } 
 }

I tried to put a breakpoints in MyReader class at line
int c=1;
but it’ s never reached. I wrote this code using this example. What could be the problem?

Answer 1

The value of ‘reading’ is a comparison between 2 byte[].

This can only be true if they both are the same object (pointer, if you will), that is, if you first call buffer = compareBuffer

What you actually want to do is compare all elements of the buffer, for example using the java.util.Arrays class :

reading = Arrays.equals(compareBuffer, buffer);