--- a/src/alice/datasegment/DataSegmentKey.java	Sun Dec 11 06:37:05 2011 +0900
+++ b/src/alice/datasegment/DataSegmentKey.java	Wed Jan 11 00:17:27 2012 +0900
@@ -1,5 +1,86 @@
 package alice.datasegment;
 
+import java.util.ArrayList;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import alice.datasegment.Command; 
+
 public class DataSegmentKey {
 	
+	private LinkedBlockingQueue<Command> cmdQueue = new LinkedBlockingQueue<Command>();
+	private ArrayList<DataSegmentValue> dataList = new ArrayList<DataSegmentValue>();
+	private ArrayList<Command> waitList = new ArrayList<Command>();
+	private AtomicInteger tailIndex = new AtomicInteger(1);
+	private Runnable keyThread;
+	
+	public DataSegmentKey() {
+		
+	}
+	
+	public void addCommand(Command cmd) {
+		cmdQueue.add(cmd);
+	}
+	
+	public void runKeyThread() {
+		keyThread = new Runnable() {
+			@Override
+			public void run() {
+				while (true) {
+					try {
+						Command cmd = cmdQueue.take();
+						switch (cmd.cmdType) {
+						case PUT:
+							int index = tailIndex.getAndIncrement();
+							dataList.add(new DataSegmentValue(index, cmd.val));
+							// run waiting peek and take
+							for (Command waitCmd : waitList) {
+								if (waitCmd.index < index) {
+									// TODO: make and send reply msg
+									
+								}
+							}
+							break;
+						case PEEK:
+							if (cmd.index >= tailIndex.get()) {
+								waitList.add(cmd);
+								break;
+							}
+							for (DataSegmentValue data : dataList) {
+								if (data.index > cmd.index) {
+									// TODO: make and send reply msg
+									
+									break;
+								}
+							}
+							break;
+						case TAKE:
+							if (cmd.index >= tailIndex.get()) {
+								waitList.add(cmd);
+								break;
+							}
+							for (DataSegmentValue data : dataList) {
+								if (data.index > cmd.index) {
+									// TODO: make and send reply msg
+
+									dataList.remove(data);
+									break;
+								}
+							}
+							break;
+						case REMOVE:
+							// TODO: implements later
+							break;
+						default:
+						}
+					} catch (InterruptedException e) {
+						// TODO Auto-generated catch block
+						e.printStackTrace();
+					}
+				}
+			}
+		};
+		keyThread.run();
+	};
+	
 }