package com.hg.ecommerce.websocket;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.hg.ecommerce.config.ProjectContainer;
import com.hg.ecommerce.dao.support.UUIDGenerator;
import com.hg.ecommerce.websocket.support.Socket;
import com.hg.ecommerce.websocket.support.SocketMessage;
/**
* ConnectHub, 在这里存放一切的连接对象
* @author Li He
*
*/
public class ConnectionHub {
public final static String uuid = UUIDGenerator.randomUUID();
private final static ConnectionHub connectionHub = new ConnectionHub();
/**
* 添加一个连接
* @param userId unique user identifier
* @param session socket object for WebSocket
* @return socket invocation
*/
public static Socket cacheSocket(String userId, WebSocketSession session){
Socket socket = new Socket(session);
connectionHub.pool.put(session.getId(), socket);
connectionHub.user_cache.put(session.getId(), userId);
return socket;
}
/**
* 添加一个连接
* @param session socket object for WebSocket
* @return socket invocation
*/
public static Socket cacheSocket(WebSocketSession session){
Socket socket = new Socket(session);
connectionHub.pool.put(session.getId(), socket);
return socket;
}
/**
* 利用session id来获取Socket Object
* @param sessionId session id
* @return Socket Object
*/
public static Socket getSocket(String sessionId){
return connectionHub.pool.get(sessionId);
}
/**
* 通过user id这种binding信息，来获取一个Socket对象
* @param uid user identifier
* @return Socket
*/
public static Socket getSocketViaBinding(String uid) {
for(Entry<String, String> entry : connectionHub.user_cache.entrySet()){
if(entry.getValue().equals(uid)){
return getSocket(entry.getKey());
}
}
return null;
}
/**
* 根据user identifier的集合仅仅获取那些在线的用户的Socket对象，
* <strong>当获取这些Socket是为了emit消息时，不推荐使用此方法，因为多次的遍历会显著降低效率</strong>
* @param uids 若干个user identifier
* @return List -- Socket集合
*/
public static List<Socket> getSocketsViaBinding(String... uids){
List<Socket> sockets = new ArrayList<Socket>();
List<String> list = Arrays.asList(uids);
list.retainAll(connectionHub.user_cache.values());
for(String uid : list){
sockets.add(getSocketViaBinding(uid));
}
return sockets;
}
/**
* 根据user identifier的集合获取那一部分offline的用户的bindings信息，当用户不在线却想要发送离线消息时，
* 可以使用此方法筛选出offline的用户
* @param uids user identifier
* @return List -- String
*/
public static List<String> getOfflineBindings(String... uids){
List<String> list = Arrays.asList(uids);
list.removeAll(connectionHub.user_cache.values());
return list;
}
/**
* 延迟绑定，绑定sessionId 到 一个userId
* @param sessionId session id
* @param userId user id
*/
public static void bindSocket(String sessionId, String userId){
connectionHub.user_cache.put(sessionId, userId);
}
/**
* 将TextMessage的raw String解析为PlainTextMessage对象
* @param message TextMessage
* @return PlainTextMessage
* @throws IOException
* @throws JsonMappingException
* @throws JsonParseException
*/
public static SocketMessage transferMessage(TextMessage message) throws IOException {
String payload = message.getPayload();
ObjectMapper mapper = ProjectContainer.getInstance(ObjectMapper.class);
SocketMessage socketMessage = mapper.readValue(payload, SocketMessage.class);
return socketMessage;
}
/**
* 删掉不活跃的连接信息
* @return 删除掉的连接数量
*/
public static int retainActiveSocket(){
int count = 0;
for(Entry<String, Socket> entry : connectionHub.pool.entrySet()){
if(!entry.getValue().isActive()){
connectionHub.pool.remove(entry.getKey());
connectionHub.user_cache.remove(entry.getKey());
count++;
}
}
return count;
}
/**
* 删除一个Connection，用户应当自行承担connection是否已经关闭的风险
* @param sessionId
* @throws IOException
*/
public static void removeSocket(String sessionId){
removeSocket(connectionHub.pool.get(sessionId));
}
/**
* safely删除一个Connection
* @param session session
* @throws IOException session关闭时可能抛出异常
*/
public static void removeSocket(Socket socket){
if(socket==null) return;
String sessionId = socket.getSessionId();
try{
if(socket.isActive()){
socket.close();
}
}catch(IOException exception){
exception.printStackTrace();
}finally{
connectionHub.pool.remove(sessionId);
connectionHub.user_cache.remove(sessionId);
}
}
/**
* return the number of the active socket
* @return int value
*/
public static int getActiveSocketCount(){
return connectionHub.pool.size();
}
/**
* Get All The Sockets Except for the one with passing id
* @param sessionId session id
* @return collection of sockets
*/
public static Collection<Socket> getOtherSockets(String sessionId){
Collection<Socket> sockets = new ArrayList<Socket>();
for(Entry<String, Socket> entry : connectionHub.pool.entrySet()){
if(entry.getKey().equals(sessionId)){
continue;
}
sockets.add(entry.getValue());
}
return sockets;
}
/**
* 广播对象为全体在线用户
* @param event event name
* @param message message object
*/
public static void emit(String event, Object message){
for(Socket socket : connectionHub.pool.values()){
socket.emit(event, message);
}
}
//*********************************** gorgeous horizontal split ***********************************//
/**
* pool's key: session id;
* pool's value: Socket object;
*/
private Map<String, Socket> pool = new HashMap<String, Socket>();
/**
* cache's key: session id;
* cache's value: user identifier;
*/
private Map<String, String> user_cache = new HashMap<String, String>();
private ConnectionHub() {}
}