import java.util.*;

public class BoundedBuffer<T> implements IBoundedBuffer<T> {
    final int NUM_BUFFER;
    volatile int count_current_elements = 0;
    Object _lock = new Object();
    ArrayList _buffer=new ArrayList();
  
    public BoundedBuffer(int size) {
        NUM_BUFFER=size;
    }
  
    public void write(T item) throws InterruptedException{
        synchronized(_lock) {
            while(count_current_elements>=NUM_BUFFER){
                try {
                    _lock.wait();
                }
                catch(InterruptedException ie) { /* ignore */ }          
            }
            _buffer.add(item);
            count_current_elements++;
            _lock.notifyAll();
        }
    }      
  
    public T read() throws InterruptedException{
        T value;
        synchronized(_lock) {
      
            while(count_current_elements<=0){
                try {
                    _lock.wait();
                }
                catch(InterruptedException ie) { /* ignore */ }
            }
            value =(T)(_buffer.remove(0));
            count_current_elements--;
            _lock.notifyAll();
        }      
        return value;
    }
}