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/*

 * Task.java - implementation of tracked task

 *

 * Copyright (c) 2006, 2007, 2008 Lukas Jelinek, http://www.aiken.cz

 *

 * ==========================================================================

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License Version 2 as

 * published by the Free Software Foundation.

 *

 * This program 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 this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * ==========================================================================

 */

package cz.aiken.util.lwtt;

import javax.swing.Timer;

import java.awt.event.*;

import java.math.*;

/**

 * This class represents a tracked task.

 * @author luk

 */

public class Task implements ActionListener, Comparable<Task> {

    private int id;

    private String name = "Unnamed task";

    private long consumption = 0L;

    private double price = 1;

    private Timer timer = null;

    /**

     * period for updating time values [ms]

     */

    public static final int PERIOD = 10000;

    /**

     * time units per hour

     */

    public static final double UNITS_PER_HOUR = 3600000;

    private ActionListener listener = null;

    private static int nextId = 0;

    /**

     * Generates a new task identifier.

     * @return new identifier

     */

    public static int getNewId() {

        int id = nextId;

        nextId++;

        return id;

    }

    /**

     * Creates a new instance of Task

     */

    public Task() {

        id = getNewId();

    }

    /**

     * Creates an instance for a task which has been already tracked.

     * @param id task identifier

     * @param name task name

     * @param consumption up to now time consumption

     * @param price price per hour

     */

    public Task(int id, String name, long consumption, double price) {

        this.id = id;

        this.name = name;

        this.consumption = consumption;

        this.price = price;

        if (id >= nextId)

            nextId = id + 1;

    }

    /**

     * Sets the listener where action events should be passed to.

     * @param al action listener

     */

    public void setActionListener(ActionListener al) {

        listener = al;

    }

    /**

     * Returns the task identifier.

     * @return task identifier

     */

    public int getId() {

        return id;

    }

    /**

     * Returns the task name.

     * @return task name

     */

    public String getName() {

        return name;

    }

    /**

     * Sets the task name.

     * @param name new task name

     */

    public void setName(String name) {

        this.name = name;

    }

    /**

     * Returns the current value of cumulative consumption [ms].

     * @return current cumulative consumption

     */

    public long getConsumption() {

        return consumption;

    }

    /**

     * Sets the task cumulative time consumption [ms].

     * @param consumption new time consumption value

     */

    public void setConsumption(long consumption) {

        this.consumption = consumption;

    }

    /**

     *  Sets the price per hour [currency unit].

     *  Changing this parameter affects the current total price of the task.

     * @param price new price value

     */

    public void setPrice(double price) {

        this.price = price;

    }

    /**

     * Returns the current price per hour [currency unit].

     * @return current price value

     */

    public double getPrice() {

        return price;

    }

    /**

     *  Returns the total price of this task [currency unit].

     * @return total price of this task

     */

    public double getTotalPrice() {

        return ((double) consumption) / UNITS_PER_HOUR * price;

    }

    /**

     * Converts the instance to the string representation. It contains

     * the task name and consumption.

     * @return string representation

     */

    @Override

    public String toString() {

        return name + "(" + Long.toString(consumption) + ")";

    }

    /**

     * Starts tracking of this task.

     */

    public void start() {

        if (timer != null)

            return;

        timer = new Timer(PERIOD, this);

        timer.start();

    }

    /**

     * Stops tracking of this task.

     */

    public void stop() {

        if (timer == null)

            return;

        timer.stop();

        timer = null;

    }

    /**

     * Checks whether the task is running.

     * @return <CODE>true</CODE> if running, <CODE>false</CODE> otherwise

     */

    public boolean isRunning() {

        return timer != null;

    }

    /**

     * Updates the time consumption value. Then it creates a new action event

     * and passes it to the assigned listener (if any).

     * @param e action event

     */

    public void actionPerformed(ActionEvent e) {

        consumption += PERIOD;

        ActionEvent e2 = new ActionEvent(this, id, "");

        if (listener != null)

            listener.actionPerformed(e2);

    }

    /**

     * Compares this task to another one. The comparison result is based

     * on task identifiers.

     * @param t another task

     * @return 1 if this class' id is greater then the given class' id,

     * -1 if both ids are equal and 0 otherwise

     */

    public int compareTo(Task t) {

        if (t == null)

            throw new NullPointerException("cannot compare to null pointer");

        if (id > t.getId())

           return 1;

        else if (id == t.getId())

            return 0;

        else

            return -1;

    }    

}