Keeps track of user's last activity on websocket for session (with websocket we would not have http requests resetting the user session timeout timer in Spring)

IdleTimeService.java

package com. .api.service;

import com. .api.domain.user.UserInfo;
import com. .api.service.message.MessageService;
import java.util.Date;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/**
 * @description Keeps track of user's last activity on websocket for session (instead of http requests resetting the timer)
 * @author Tobin
 */
@Service
public class IdleTimeService {

    @Autowired
    private SessionService sessionService;

    private class IdleTimer {

        public IdleTimer(Integer maxIdleTime) {
            this.maxIdleTime = maxIdleTime;
            this.lastActivityTime = new Date();
        }
        private Date lastActivityTime;
        private Integer maxIdleTime;

        public Integer getMaxIdleTime() {
            return maxIdleTime;
        }

        public void setMaxIdleTime(Integer maxIdleTime) {
            this.maxIdleTime = maxIdleTime;
        }

        public Date getLastActivityTime() {
            return lastActivityTime;
        }

        public void setLastActivityTime(Date lastActivityTime) {
            this.lastActivityTime = lastActivityTime;
        }
    }

    private final Map<String, IdleTimer> userIdleMap = new ConcurrentHashMap<>();

    private IdleTimeService() {

    }

    public void userActivity(UserInfo userInfo, Date date) {
        if (userIdleMap.containsKey(userInfo.getUsername())) {
            //Update user's entry if it exists
            userIdleMap.get(userInfo.getUsername()).setLastActivityTime(date);
        } else {
            //Create new entry
            IdleTimer idleTimer = new IdleTimer(userInfo.getUserSettings().getAutoLogoutInactivityMinutes());
            userIdleMap.put(userInfo.getUsername(), idleTimer);
        }

    }

    //Called from CRON every minute
    public void checkExpiry() {

        Iterator<String> itr = userIdleMap.keySet().iterator();
        while (itr.hasNext()) {
            String username = itr.next();
            IdleTimer idleTimer = userIdleMap.get(username);
            //If current time is greater than the last activity time plus the max idle time, logout.
            if (new Date().getTime() > idleTimer.getLastActivityTime().getTime() + idleTimer.getMaxIdleTime() * 1000 * 60) {
                sendExpiry(username);
                removeUser(username); //TODO make removal part of session service
            }
        }
    }

    private void sendExpiry(String username) {

        sessionService.userIdleTimeout(username);

    }

    public void removeUser(String username) {
        if (userIdleMap.containsKey(username)) {
            userIdleMap.remove(username);
        }

    }

    public void updateInactivityTime(UserInfo userInfo, Integer maxIdleTime) {
        //if admin updates user and they are not logged in
        if (userIdleMap.containsKey(userInfo.getUsername())) {
            userIdleMap.get(userInfo.getUsername()).setMaxIdleTime(maxIdleTime);
        }

    }
}