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--- lab7 [2016/02/24 14:05] – created franck
+++ lab7 [2018/03/11 23:19] (current) – franck
@@ Line 1: / Line 1: @@
-Consider the following app.
+====== Lab 7 ======
-<html>
-<pre>
+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.
-public class ComputeSquareRoot {
+<code java>
-    public static void main(String[] args) {
+/**
-          double data = 3.1415926;
+ * A stack.  It stores integers.
-          System.out.println("The square root of " + data + " is " + StrictMath.sqrt(data));
+ *
-    }
+ * @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;
+  }
 }
-</pre>
+</code>
-</html>
+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>
-  - Develop a model class so that the above app can be verified with JPF.  [[https://en.wikipedia.org/wiki/Methods_of_computing_square_roots|This]] Wikipedia page might be helpful.
-  - Develop a native peer so that the above app can be verified with JPF.