--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/ac/ryukyu/treevnc/MulticastQueue.java	Tue Jul 24 15:46:36 2012 +0900
@@ -0,0 +1,87 @@
+package ac.ryukyu.treevnc;
+
+import java.util.concurrent.CountDownLatch;
+
+public class MulticastQueue<T>
+{
+	
+	Node<T> tail;
+	
+	public MulticastQueue()
+	{
+		tail = new Node<T>(null);
+	}
+
+	public synchronized void put(T item)
+	{
+		Node<T> next = new Node<T>(item);
+		tail.set(next);
+		tail = next;
+	}
+	
+	public Client<T> newClient()
+	{
+		return new Client<T>(tail);
+	}
+	
+	static class Client<T>
+	{
+		Node<T> node;
+		
+		Client(Node<T> tail)
+		{
+			node = tail;
+		}
+		
+		synchronized public T poll()
+		{
+			Node<T> next = null;
+			T item = null;
+			do {
+				try {
+					next = node.next();
+				}catch(InterruptedException _e){
+					continue;
+				}
+//				item = node.getItem();
+				item = next.getItem();				
+				node = next;
+			} while ( item == null);
+			return item;
+		}
+	}
+	
+	static class Node<T>
+	{
+		private T item;
+		private Node<T> next;
+		private CountDownLatch latch;
+		
+		public Node(T item)
+		{
+			this.item = item;
+			this.next = null;
+			latch = new CountDownLatch(1);
+		}
+		
+		synchronized public T getItem() {
+			return item;
+		}
+
+		public void set(Node<T> next)
+		{
+			this.next = next;
+			latch.countDown();
+		}
+		
+		public Node<T> next() throws InterruptedException
+		{
+			latch.await();
+			return next;
+		}
+
+		synchronized public void clear() {
+			item = null;
+		}
+	}
+}