====== Lab 7 ======

In this lab, we consider a concurrent stack.  We start from the following skeleton of a sequential stack.  Note that the class Stack does not implement a stack correctly.
<code java>
/**
 * A stack.  It stores integers.
 *
 * @author
 */
public class Stack {
  private int[] content;
  private int size;

  /*
   * The maximal number of integers that can be stored in a stack.
   */
  private final static int CAPACITY = 5;

  /**
   * Initializes this stack to be empty.
   */
  public Stack() {
    this.content = new int[Stack.CAPACITY];
    this.size = 0;
  }

  /**
   * Pushes the given integer onto this stack.
   *
   * @param value the integer to be pushed onto this stack.
   */
  public void push(int value) {
    this.content[this.size] = value;
    this.size++;
    System.out.printf("Push %d\n", value);
  }

  /**
   * Pops the top of this stack and returns the integer.
   *
   * @return the top of this stack.
   */
  public int pop() {
    this.size--;
    int value = this.content[this.size];
    System.out.printf("Pop %d\n", value);
    return value;
  }
}
</code>

Implement the following classes.
  * The class Pusher.  Each Pusher object is a Thread that pushes the integers 0, 1, ..., 9 onto a stack.  The stack is provided as an argument to the constructor of the Pusher class.  The jar file {{:pop.jar|pop.jar}} contains the class Popper.  Each Popper object is a Thread that pops ten integers from a stack.  The stack is provided as an argument to the constructor of the Popper class.
  * The class Stack.  This class is based on the above skeleton and allows Threads to concurrently call the push and pop methods on the stack.
  * The class Main.  This class only contains a main method.  In the main method, a number of Popper and Pusher objects are created (for example, 10 Poppers and 5 Pushers) and all these Threads are run concurrently.

To receive feedback, submit your code using the submit command:\\
<code>
submit 4315 lab7 <name of class>.java
</code>