Statistic.java

/**
 * Copyright 2010 the original author or authors.
 * 
 * This file is part of Zksample2. http://zksample2.sourceforge.net/
 *
 * Zksample2 is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Zksample2 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Zksample2.  If not, see <http://www.gnu.org/licenses/gpl.html>.
 */
package de.forsthaus.statistic;

import java.io.Serializable;
import java.util.List;

import org.zkoss.zk.ui.Desktop;
import org.zkoss.zk.ui.Session;
import org.zkoss.zk.ui.util.Monitor;

/**
 * An implementation of {@link Monitor} to accumulate statistic data in memory.
 * 
 * <p>
 * It has no effect until you specify it in WEB-INF/zk.xml.
 * 
 * @author tomyeh
 * @changes 16.07.2009 / addapted for static access to the values. <br>
 */
public class Statistic implements Monitor, Serializable {

	private static final long serialVersionUID = 1L;
	private transient final long _startTime;
	private transient int _nsess, _actsess, _ndt, _actdt, _nupd, _actupd;

	// new
	private static Statistic stat;

	public Statistic() {
		_startTime = System.currentTimeMillis();
		stat = this;
	}

	public static Statistic getStatistic() {
		return stat;
	}

	public double getRuningHours() {
		long v = System.currentTimeMillis() - getStartTime();
		return ((double) v) / 3600000;
	}

	/**
	 * Returns when the server (actually, this monitor) started.
	 */
	public long getStartTime() {
		return _startTime;
	}

	/**
	 * Returns the total number of sessions that have been created since the
	 * server started.
	 */
	public int getTotalSessionCount() {
		return _nsess;
	}

	/**
	 * Returns the number of active sessions.
	 */
	public int getActiveSessionCount() {
		return _actsess;
	}

	/**
	 * Returns the average number of sessions being created in an hour.
	 */
	public double getAverageSessionCount() {
		return _nsess / getEscapedHours();
	}

	/**
	 * Returns the total number of desktops that have been created since the
	 * server started.
	 */
	public int getTotalDesktopCount() {
		return _ndt;
	}

	/**
	 * Returns the number of active desktops.
	 */
	public int getActiveDesktopCount() {
		return _actdt;
	}

	/**
	 * Returns the average number of desktops being created in an hour.
	 */
	public double getAverageDesktopCount() {
		return _ndt / getEscapedHours();
	}

	/**
	 * Returns the total number of asynchronous updates that have been received
	 * since the server started.
	 */
	public int getTotalUpdateCount() {
		return _nupd;
	}

	/**
	 * Returns the number of active asynchronous updates.
	 */
	public int getActiveUpdateCount() {
		return _actupd;
	}

	/**
	 * Returns the average number of asynchronous updates being created in an
	 * hour.
	 */
	public double getAverageUpdateCount() {
		return _nupd / getEscapedHours();
	}

	/**
	 * Returns how many hours escaped since the server started.
	 */
	private double getEscapedHours() {
		long v = System.currentTimeMillis() - _startTime;
		return ((double) v) / 3600000;
	}

	// -- Monitor --//
	synchronized public void sessionCreated(Session sess) {
		++_nsess;
		++_actsess;
	}

	synchronized public void sessionDestroyed(Session sess) {
		--_actsess;
	}

	synchronized public void desktopCreated(Desktop desktop) {
		++_ndt;
		++_actdt;
	}

	synchronized public void desktopDestroyed(Desktop desktop) {
		--_actdt;
	}

	synchronized public void beforeUpdate(Desktop desktop, List requests) {
		++_nupd;
		++_actupd;
	}

	synchronized public void afterUpdate(Desktop desktop) {
		--_actupd;
	}
}