/**
* Copyright (c) 2005-2012 https://github.com/zhangkaitao
*
* Licensed under the Apache License, Version 2.0 (the "License");
*/
package com.sishuok.chapter3.web.servlet.chat;
import javax.servlet.AsyncContext;
import javax.servlet.AsyncEvent;
import javax.servlet.AsyncListener;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedDeque;
/**
* <p>User: Zhang Kaitao
* <p>Date: 13-7-15 下午9:03
* <p>Version: 1.0
*/
public class MsgPublisher {
private volatile Map<String, Queue<AsyncContext>> usernameToAsyncContextMap = new ConcurrentHashMap();
private MsgPublisher() {
}
private static MsgPublisher instance = new MsgPublisher();
public static MsgPublisher getInstance() {
return instance;
}
public Collection<String> getLoginUsers() {
return new HashSet(usernameToAsyncContextMap.keySet());
}
public void startAsync(HttpServletRequest req, final String username) {
//1、开启异步
final AsyncContext asyncContext = req.startAsync();
asyncContext.setTimeout(30L * 1000);
//将异步上下文加入到队列中，这样在未来可以推送消息
Queue<AsyncContext> queue = usernameToAsyncContextMap.get(username);
if(queue == null) {
queue = new ConcurrentLinkedDeque();
usernameToAsyncContextMap.put(username, queue);
}
queue.add(asyncContext);
asyncContext.addListener(new AsyncListener() {
@Override
public void onComplete(final AsyncEvent event) throws IOException {
Queue<AsyncContext> queue = usernameToAsyncContextMap.get(username);
if(queue != null) {
queue.remove(event.getAsyncContext());
}
}
@Override
public void onTimeout(final AsyncEvent event) throws IOException {
event.getAsyncContext().complete();
}
@Override
public void onError(final AsyncEvent event) throws IOException {
Queue<AsyncContext> queue = usernameToAsyncContextMap.get(username);
if(queue != null) {
queue.remove(event.getAsyncContext());
}
}
@Override
public void onStartAsync(final AsyncEvent event) throws IOException {
}
});
}
public void login(String username) {
if (!usernameToAsyncContextMap.containsKey(username)) {
StringBuilder data = new StringBuilder();
data.append("{");
data.append("\"type\" : \"login\"");
data.append(",\"username\" : \"" + username + "\"");
data.append("}");
publish(null, username, data.toString());
}
}
public void logout(String username) {
if(username == null) {
return;
}
Queue<AsyncContext> queue = usernameToAsyncContextMap.get(username);
if(queue != null && queue.size() == 0) {
StringBuilder data = new StringBuilder();
data.append("{");
data.append("\"type\" : \"logout\"");
data.append(",\"username\" : \"" + username + "\"");
data.append("}");
publish(null, username, data.toString());
usernameToAsyncContextMap.remove(username);
}
}
public void send(String receiver, String sender, String msg) {
StringBuilder data = new StringBuilder();
data.append("{");
data.append("\"type\" : \"msg\"");
data.append(",\"username\" : \"" + sender + "\"");
data.append(",\"msg\" : \"" + msg + "\"");
data.append("}");
publish(receiver, sender, data.toString());
}
/**
*
* @param receiver 如果为空 表示发送给所有人
* @param sender
* @param data
*/
private void publish(String receiver, String sender, String data) {
if (receiver == null || receiver.trim().length() == 0) {//发送给所有人
for (String loginUsername : usernameToAsyncContextMap.keySet()) {
if (loginUsername.equals(sender)) {
continue;
}
Queue<AsyncContext> queue = usernameToAsyncContextMap.get(loginUsername);
if(queue != null) {
Iterator<AsyncContext> iter = queue.iterator();
while(iter.hasNext()) {
AsyncContext asyncContext = iter.next();
try {
ServletResponse response = asyncContext.getResponse();
PrintWriter out = response.getWriter();
out.write(data);
out.flush();
asyncContext.complete();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
} else { //私人消息
Queue<AsyncContext> queue = usernameToAsyncContextMap.get(receiver);
if(queue != null) {
Iterator<AsyncContext> iter = queue.iterator();
while(iter.hasNext()) {
AsyncContext asyncContext = iter.next();
try {
ServletResponse response = asyncContext.getResponse();
PrintWriter out = response.getWriter();
out.write(data);
out.flush();
asyncContext.complete();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
}