Server Architecture
We have exposed the MINA Application Architecture in the previous section. Let's now focus on the Server Architecture. Basically, a Server listens on a port for incoming requests, process them and send replies. It also creates and handles a session for each client (whenever we have a TCP or UDP based protocol), this will be explain more extensively in the chapter 4.
我在上一章節中介紹了mina的應用架構。讓我們來了解一個服務端的架構。
服務端主要監聽端口進來的請求，處理請求和發送回覆，爲處理每一個客戶端(基本tcp 或者udp協議)創建一個會話 。在第4個會更詳細的介紹。
- IOAcceptor listens on the network for incoming connections/packets
- For a new connection, a new session is created and all subsequent request from IP Address/Port combination are handled in that Session
- All packets received for a Session, traverses the Filter Chain as specified in the diagram. Filters can be used to modify the content of packets (like converting to Objects, adding/removing information etc). For converting to/from raw bytes to High Level Objects, PacketEncoder/Decoder are particularly useful
- Finally the packet or converted object lands in
IOHandler.IOHandlers can be used to fulfill business needs.
IOAcceptor 監聽來自網絡的連接和數據包
一個新鏈接，創建一個會話，這個ip地趾端口尾隨而來的請求在這個會話中處理。
會話所有的數據包會經過filter chain 。filter 被用修改數據包的內容，爲轉換byte爲更高的對象(如string等)，數據編碼/解碼常用到。
最數據包被轉換成對象傳給iohanlder ，iohanlder 被用於滿足業務邏輯的需求。
Session creation
Whenever a client connects on a MINA server, we will create a new session to store persistent data into it. Even if the protocol is not connected, this session will be created. The following schema shows how MINA handles incoming connections :
當客戶連接mina服務端,將會創建一個新的會話用於存儲待久數據，甚至這個協議沒有連接這個session也被創建。
下面的說明mina是如何處理請求鏈接的。
Incoming messages processing
We will now explain how MINA processes incoming messages.
Assuming that a session has been created, any new incoming message will result in a selector being waken up
假如一個會話被創建。一個新消息的到將使一個選擇器被人喚醒