http://www.dsalgo.com/2013/03/distributed-circular-linked-list-sum.html

DistributedCircularListSum.java

@@ -0,0 +1,106 @@
+/*
+http://www.dsalgo.com/2013/03/distributed-circular-linked-list-sum.html
+*/
+
+package com.dsalgo;
+
+class DistributedCircularListSum
+{
+ public static volatile boolean startFlag = false;
+ private static Boolean flag = false;
+
+ public static void main(String[] args)
+ {
+  Node a = new Node(1);
+  Node b = new Node(2);
+  Node c = new Node(3);
+  Node d = new Node(4);
+  Node e = new Node(5);
+  a.next = b;
+  b.next = c;
+  c.next = d;
+  d.next = e;
+  e.next = a;
+  startFlag = true;
+ }
+
+ private static class Node
+ {
+  Node next;
+  int value;
+  Integer data;
+
+  public Node(int value)
+  {
+   this.value = value;
+   new Thread(new NodeRunner(this, value)).start();
+  }
+
+  public synchronized void send(int data)
+  {
+   this.data = data;
+  }
+
+ }
+
+ private static class NodeRunner implements Runnable
+ {
+  Node node;
+  int id;
+
+  public NodeRunner(Node node, int id)
+  {
+   this.node = node;
+   this.id = id;
+  }
+
+  @Override
+  public void run()
+  {
+   while (!startFlag)
+   {
+   }
+
+   boolean isFirst = false;
+   synchronized (flag)
+   {
+    if (flag == false)
+    {
+     flag = true;
+     isFirst = true;
+    }
+   }
+   if (isFirst)
+    node.next.send(node.value);
+   else
+   {
+    while (node.data == null)
+    {
+     try
+     {
+      Thread.sleep(10);
+     } catch (InterruptedException e)
+     {
+
+     }
+    }
+    int sum = node.value + node.data;
+    node.data = null;
+    node.next.send(sum);
+   }
+   while (node.data == null)
+   {
+    try
+    {
+     Thread.sleep(10);
+    } catch (InterruptedException e)
+    {
+
+    }
+   }
+   System.out.println("id:" + id + "sum:" + node.data);
+   node.next.send(node.data);
+  }
+ }
+}
+