/* Code of Figure 14.6, pages 641-642 from
   Kenneth C. Louden, Programming Languages
   Principles and Practice 2nd Edition
   Copyright (C) Brooks-Cole/ITP, 2003
*/

import java.io.*;

class BoundedBuffer {

    public static void main(String[] args) {
        Buffer buffer = new Buffer(5); // buffer has size 5
        Producer prod = new Producer(buffer);
        Consumer cons = new Consumer(buffer);
        Thread read = new Thread(prod);
        Thread write = new Thread(cons);
        read.start();
        write.start();
        try {
          read.join();
          write.interrupt();
        }
        catch (InterruptedException e) {}
    }
}

class Buffer {
    private final char[] buf;
    private int start = -1;
    private int end = -1;
    private int size = 0;

    public Buffer(int length) {
        buf = new char[length];
    }

    public boolean more()
    { return size > 0; }

    public synchronized void put(char ch)
    { try {
        while (size == buf.length) wait();
        end = (end+1) % buf.length;
        buf[end] = ch;
        size++;
        notifyAll();
      }
      catch (InterruptedException e)
      { Thread.currentThread().interrupt(); }
    }

    public synchronized char get()
    { try {
        while (size == 0) wait();
        start = (start+1) % buf.length;
        char ch = buf[start];
        size--;
        notifyAll();
        return ch;
      }
      catch (InterruptedException e)
      { Thread.currentThread().interrupt(); }
      return 0;
    }
}

class Consumer implements Runnable {
    private final Buffer buffer;

    public Consumer(Buffer b)
    { buffer = b; 
    }

    public void run() {
            while (!Thread.currentThread().isInterrupted())
            {   char c = buffer.get();
                System.out.print(c);
            }
            while(buffer.more()) // clean-up
            {   char c = buffer.get();
                System.out.print(c);
            }
    }
}

class Producer implements Runnable {
    private final Buffer buffer;
    private final InputStreamReader in
        = new InputStreamReader(System.in);

    public Producer(Buffer b) { buffer = b; }

    public void run() {
        try {
          while (!Thread.currentThread().isInterrupted()) {
             int c = in.read();
             if (c == -1) break; // -1 is end of file
             buffer.put((char)c);
          }
        }
        catch (IOException e) {}
    }
}