import java.io.*;

// the mutex class to keep track of the number of spawned threads
// so that the thread that spawned the threads can wait for all of
// the spawned threads are done.
public class ThreadMutex
{

	 ///////////////////////////////////////////
	 // private variables

	 // the counter to count the number of threads to wait for
	 // to end
	 private int ThreadCount;

	 // the print stream to output from the services
	 PrintStream Outstream;
	 
	 
	 // constructor for this class
	 ThreadMutex(int numOfThreads, PrintStream out)
	 {

		  ThreadCount = numOfThreads;

		  Outstream = out;
		  
	 }

	 // output to the outstream stored in here
	 public synchronized void outputToStream(ByteArrayOutputStream byteStream)
	 {

		  try {
				
				byteStream.writeTo(Outstream);
		  } catch (IOException ex) {
		  }
		  
	 }
	 
	 
	 // just wait until the thread count is == 0
	 public synchronized void waitForThreads()
	 {
		  try {
				
				while(ThreadCount > 0)
					 wait();
		  } catch (InterruptedException ex) {
		  }
		  
	 }

	 // decrement the counter
	 public synchronized void decrementThreadCount()
	 {
		  ThreadCount--;
		  notifyAll();
	 }
	 
	 
}