jodd.servlet.SessionMonitor Maven / Gradle / Ivy
// Copyright (c) 2003-present, Jodd Team (http://jodd.org)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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package jodd.servlet;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
/**
* Session monitor keep map of sessions and allow registration of
* session listeners in runtime.
*/
public class SessionMonitor implements HttpSessionListener {
protected static SessionMonitor sessionMonitor;
protected List listeners;
protected ConcurrentMap sessionMap;
/**
* Creates new session monitor.
*/
public SessionMonitor() {
if (sessionMonitor == null) {
sessionMonitor = this;
listeners = new CopyOnWriteArrayList<>();
sessionMap = new ConcurrentHashMap<>();
}
}
/**
* Returns singleton instance of SessionMonitor.
*/
public static SessionMonitor getInstance() {
return sessionMonitor;
}
// ---------------------------------------------------------------- listeners
/**
* Registers new session listener.
*/
public void registerListener(final HttpSessionListener listener) {
listeners.add(listener);
}
/**
* Removes existing session listener.
*/
public void removeListener(final HttpSessionListener listener) {
listeners.remove(listener);
}
// ---------------------------------------------------------------- broadcast
/**
* Stores session in map and broadcasts event to registered listeners.
*/
@Override
public void sessionCreated(final HttpSessionEvent httpSessionEvent) {
HttpSession session = httpSessionEvent.getSession();
sessionMap.putIfAbsent(session.getId(), session);
for (HttpSessionListener listener : listeners) {
listener.sessionCreated(httpSessionEvent);
}
}
/**
* Removes session from a map and broadcasts event to registered listeners.
*/
@Override
public void sessionDestroyed(final HttpSessionEvent httpSessionEvent) {
HttpSession session = httpSessionEvent.getSession();
sessionMap.remove(session.getId());
for (HttpSessionListener listener : listeners) {
listener.sessionDestroyed(httpSessionEvent);
}
}
// ---------------------------------------------------------------- map
/**
* Returns session for given session id. Returns null
* if session expired.
*/
public HttpSession getSession(final String sessionId) {
return sessionMap.get(sessionId);
}
/**
* Returns iterator for all stored session IDs.
* Keep in mind that session may NOT longer
* exist during the iteration!
*/
public Iterator iterator() {
return sessionMap.keySet().iterator();
}
// ---------------------------------------------------------------- close
/**
* Destroys this session monitor by removing all collected resources.
*/
public void destroy() {
listeners.clear();
sessionMap.clear();
}
}