Well, in order to start with the question, first I want to clarify that I am a newbie in Java programming, so, excuse me if I ask something unconsciously.
Recently I have been working on a project that consists mainly on managing SIP VoIP calls with the help of a library that does all the laborious business related to structuring and managing SIP protocol, in few words, just a kind of a basic softphone. This library also is in charge of capturing, sending and transmitting the audio to the respective sources and targets.
My problem is that I want to control the system volume using a slider within a graphical interface I created, but what I do not know is how to pass the FloatControl parameter to the slider due to the following circumstances:
If the slider needs to be created and shown from the time I start the program, What FloatControl parameter I should give to the JSlider object?, because the audio ports are open by the library methods or in other words, the instance of the JavaSoundManager object is created only when I make o receive a call. As far as I know, to get an audio line, it is needed to get a System Mixer, then LineInfos, later SourceLine and finally open this line, just at this point, I am able to create de FloatControl parameter of the SourceLine and pass it to the JSlider object, or, is there another way to do it?
Just for you to have a bigger picture of the situation, I am still not clear hundred percent how the library works in general, but checking its classes, I notice the JavaSoundManager class uses doPrivileged and Synchronized methods which I am not acquaintance with, these are used to open an close the audio lines when the calls are stablished.
In resume, these are my doubts:
How can I have access to a variable or parameter inside a library class if this is privated and does not have any getter o setter?
How can I pass the FloatControl parameter to the JSlider object in order to control de volume of the line created by the JavaSoundManager class?
And finally, is there a way to modify a class inside a library? Keeping in mind the library is a .jar file.
This is the code of the JavaSoundManager class:
public class JavaSoundManager {
private AudioFormat audioFormat;
private TargetDataLine targetDataLine;
private SourceDataLine sourceDataLine;
private Object sourceDataLineMute;
private DataLine.Info targetInfo;
private DataLine.Info sourceInfo;
private FileOutputStream microphoneOutput;
private FileOutputStream speakerInput;
private boolean mediaDebug;
private Logger logger;
public JavaSoundManager(boolean mediaDebug, Logger logger)
extends AbstractManager{
this.mediaDebug = mediaDebug;
this.logger = logger;
audioFormat = new AudioFormat(8000, 16, 1, true, false);
targetInfo = new DataLine.Info(TargetDataLine.class, audioFormat);
sourceInfo = new DataLine.Info(SourceDataLine.class, audioFormat);
sourceDataLineMute = new Object();
}
@Override
public void init() {
logger.debug("openAndStartLines");
if (mediaDebug) {
SimpleDateFormat simpleDateFormat
= new SimpleDateFormat("yyyy-MM-dd_HH-mm-ss");
String date = simpleDateFormat.format(new Date());
StringBuffer buf = new StringBuffer();
buf.append(MEDIA_DIR).append(File.separator);
buf.append(date).append("_");
buf.append(audioFormat.getEncoding()).append("_");
buf.append(audioFormat.getSampleRate()).append("_");
buf.append(audioFormat.getSampleSizeInBits()).append("_");
buf.append(audioFormat.getChannels()).append("_");
buf.append(audioFormat.isBigEndian() ? "be" : "le");
try {
microphoneOutput = new FileOutputStream(buf.toString()
+ "-microphone-output");
speakerInput = new FileOutputStream(buf.toString()
+ "-speaker-input");
} catch (FileNotFoundException e) {
logger.error("cannot-create-file", e);
return;
}
}
AccessController.doPrivileged(
new PrivilegedAction<Void>() {
@Override
public Void run() {
try {
targetDataLine = (TargetDataLine) AudioSystem.getLine(targetInfo);
targetDataLine.open(audioFormat);
} catch (LineUnavailableException e) {
logger.error("target-line-unavailable", e);
return null;
} catch (SecurityException e) {
logger.error("security-exception", e);
return null;
} catch (Throwable t) {
logger.error("throwable " + t.getMessage());
return null;
}
targetDataLine.start();
synchronized (sourceDataLineMute) {
try {
sourceDataLine = (SourceDataLine) AudioSystem.getLine(sourceInfo);
sourceDataLine.open(audioFormat);
} catch (LineUnavailableException e) {
logger.error("source line unavailable", e);
return null;
}
sourceDataLine.start();
}
return null;
}
});
}
@Override
public synchronized void close() {
logger.debug("closeLines");
if (microphoneOutput != null) {
try {
microphoneOutput.close();
} catch (IOException e) {
logger.error("cannot-close-file", e);
}
microphoneOutput = null;
}
if (speakerInput != null) {
try {
speakerInput.close();
} catch (IOException e) {
logger.error("cannot-close-file", e);
}
speakerInput = null;
}
AccessController.doPrivileged(new PrivilegedAction<Void>() {
@Override
public Void run() {
if (targetDataLine != null) {
targetDataLine.close();
targetDataLine = null;
}
synchronized (sourceDataLineMute) {
if (sourceDataLine != null) {
sourceDataLine.drain();
sourceDataLine.stop();
sourceDataLine.close();
sourceDataLine = null;
}
}
return null;
}
});
}
@Override
public synchronized byte[] readData() {
if (targetDataLine == null) {
return null;
}
int ready = targetDataLine.available();
while (ready == 0) {
try {
Thread.sleep(2);
ready = targetDataLine.available();
} catch (InterruptedException e) {
return null;
}
}
if (ready <= 0) {
return null;
}
byte[] buffer = new byte[ready];
targetDataLine.read(buffer, 0, buffer.length);
if (mediaDebug) {
try {
microphoneOutput.write(buffer, 0, buffer.length);
} catch (IOException e) {
logger.error("cannot-write-to-file", e);
return null;
}
}
return buffer;
}
@Override
public int writeData(byte[] buffer, int offset, int length) {
int numberOfBytesWritten;
synchronized (sourceDataLineMute) {
if (sourceDataLine == null) {
return 0;
}
numberOfBytesWritten = sourceDataLine.write(buffer, offset, length);
}
if (mediaDebug) {
try {
speakerInput.write(buffer, offset, numberOfBytesWritten);
} catch (IOException e) {
logger.error("cannot-write-to-file", e);
return -1;
}
}
return numberOfBytesWritten;
}
}
Let me know if you need somthing else to be clearer, and thank you all in advance.
