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	/*
	* Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.management;

	import java.lang.management.MemoryUsage;
	import java.util.Iterator;
	import java.util.Map;
	import java.util.HashMap;

	/**
	* An abstract sensor.
	*
	* <p>
	* A <tt>AbstractSensor</tt> object consists of two attributes:
	* <ul>
	* <li><tt>on</tt> is a boolean flag indicating if a sensor is
	* triggered. This flag will be set or cleared by the
	* component that owns the sensor.</li>
	* <li><tt>count</tt> is the total number of times that a sensor
	* has been triggered.</li>
	* </ul>
	*
	* @author Mandy Chung
	* @since 1.5
	*/

	public abstract class Sensor {
	private Object lock;
	private String name;
	private long count;
	private boolean on;

	/**
	* Constructs a <tt>Sensor</tt> object.
	*
	* @param name The name of this sensor.
	*/
	public Sensor(String name) {
	this.name = name;
	this.count = 0;
	this.on = false;
	this.lock = new Object();
	}

	/**
	* Returns the name of this sensor.
	*
	* @return the name of this sensor.
	*/
	public String getName() {
	return name;
	}

	/**
	* Returns the total number of times that this sensor has been triggered.
	*
	* @return the total number of times that this sensor has been triggered.
	*/
	public long getCount() {
	synchronized (lock) {
	return count;
	}
	}

	/**
	* Tests if this sensor is currently on.
	*
	* @return <tt>true</tt> if the sensor is currently on;
	* <tt>false</tt> otherwise.
	*
	*/
	public boolean isOn() {
	synchronized (lock) {
	return on;
	}
	}

	/**
	* Triggers this sensor. This method first sets this sensor on
	* and increments its sensor count.
	*/
	public void trigger() {
	synchronized (lock) {
	on = true;
	count++;
	}
	triggerAction();
	}

	/**
	* Triggers this sensor. This method sets this sensor on
	* and increments the count with the input <tt>increment</tt>.
	*/
	public void trigger(int increment) {
	synchronized (lock) {
	on = true;
	count += increment;
	// Do something here...
	}
	triggerAction();
	}

	/**
	* Triggers this sensor piggybacking a memory usage object.
	* This method sets this sensor on
	* and increments the count with the input <tt>increment</tt>.
	*/
	public void trigger(int increment, MemoryUsage usage) {
	synchronized (lock) {
	on = true;
	count += increment;
	// Do something here...
	}
	triggerAction(usage);
	}

	/**
	* Clears this sensor.
	*/
	public void clear() {
	synchronized (lock) {
	on = false;
	}
	clearAction();
	}


	/**
	* Clears this sensor
	* and increments the count with the input <tt>increment</tt>.
	*/
	public void clear(int increment) {
	synchronized (lock) {
	on = false;
	count += increment;
	}
	clearAction();
	}

	public String toString() {
	return "Sensor - " + getName() +
	(isOn() ? " on " : " off ") +
	" count = " + getCount();
	}

	abstract void triggerAction();
	abstract void triggerAction(MemoryUsage u);
	abstract void clearAction();
	}

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