add packet structure

ChatApp/src/network/protocol/packets/RoomListPacket.java

@@ -0,0 +1,28 @@
+package network.protocol.packets;
+
+import java.util.ArrayList;
+
+import network.protocol.Packet;
+import network.protocol.PacketVisitor;
+import network.protocol.Packets;
+
+public class RoomListPacket extends Packet {
+
+	static private final long serialVersionUID = Packets.Login.ordinal();
+
+	private final ArrayList<String> roomNames;
+
+	public RoomListPacket(ArrayList<String> roomNames) {
+		this.roomNames = roomNames;
+	}
+
+	public ArrayList<String> getRoomNames() {
+		return roomNames;
+	}
+
+	@Override
+	public void accept(PacketVisitor packetVisitor) {
+		packetVisitor.visitPacket(this);
+	}
+
+}