/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library 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 Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ---------
 * Task.java
 * ---------
 * (C) Copyright 2003, 2004, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: Task.java,v 1.4.2.1 2005/10/25 21:31:44 mungady Exp $
 *
 * Changes
 * -------
 * 10-Jan-2003 : Version 1 (DG);
 * 16-Sep-2003 : Added percentage complete (DG);
 * 30-Jul-2004 : Added clone() and equals() methods and implemented 
 *               Serializable (DG);
 *
 */

package org.jfree.data.gantt;

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

import org.jfree.data.time.SimpleTimePeriod;
import org.jfree.data.time.TimePeriod;
import org.jfree.util.ObjectUtilities;
import org.jfree.util.PublicCloneable;

/**
 * A simple representation of a task.  The task has a description and a 
 * duration.  You can add sub-tasks to the task.
 */
public class Task implements Cloneable, PublicCloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = 1094303785346988894L;
    
    /** The task description. */
    private String description;

    /** The time period for the task (estimated or actual). */
    private TimePeriod duration;
    
    /** The percent complete (<code>null</code> is permitted). */
    private Double percentComplete;

    /** Storage for the sub-tasks (if any). */
    private List subtasks;

    /**
     * Creates a new task.
     *
     * @param description  the task description (<code>null</code> not 
     *                     permitted).
     * @param duration  the task duration (<code>null</code> permitted).
     */
    public Task(String description, TimePeriod duration) {
        if (description == null) {
            throw new IllegalArgumentException("Null 'description' argument.");
        }
        this.description = description;
        this.duration = duration;
        this.percentComplete = null;
        this.subtasks = new java.util.ArrayList();
    }
    
    /**
     * Creates a new task.
     * 
     * @param description  the task description (<code>null</code> not 
     *                     permitted).
     * @param start  the start date (<code>null</code> not permitted).
     * @param end  the end date (<code>null</code> not permitted).
     */
    public Task(String description, Date start, Date end) {
        this(description, new SimpleTimePeriod(start, end));
    }

    /**
     * Returns the task description.
     *
     * @return The task description (never <code>null</code>).
     */
    public String getDescription() {
        return this.description;
    }

    /**
     * Sets the task description.
     *
     * @param description  the description (<code>null</code> not permitted).
     */
    public void setDescription(String description) {
        if (description == null) {
            throw new IllegalArgumentException("Null 'description' argument.");
        }
        this.description = description;
    }

    /**
     * Returns the duration (actual or estimated) of the task.
     *
     * @return The task duration (possibly <code>null</code>).
     */
    public TimePeriod getDuration() {
        return this.duration;
    }

    /**
     * Sets the task duration (actual or estimated).
     *
     * @param duration  the duration (<code>null</code> permitted).
     */
    public void setDuration(TimePeriod duration) {
        this.duration = duration;
    }
    
    /**
     * Returns the percentage complete for this task.
     * 
     * @return The percentage complete (possibly <code>null</code>).
     */
    public Double getPercentComplete() {
        return this.percentComplete;
    }
    
    /**
     * Sets the percentage complete for the task.
     * 
     * @param percent  the percentage (<code>null</code> permitted).
     */
    public void setPercentComplete(Double percent) {
        this.percentComplete = percent;
    }

    /**
     * Sets the percentage complete for the task.
     * 
     * @param percent  the percentage.
     */
    public void setPercentComplete(double percent) {
        setPercentComplete(new Double(percent));
    }
    
    /**
     * Adds a sub-task to the task.
     *
     * @param subtask  the subtask (<code>null</code> not permitted).
     */
    public void addSubtask(Task subtask) {
        if (subtask == null) {
            throw new IllegalArgumentException("Null 'subtask' argument.");
        }
        this.subtasks.add(subtask);
    }

    /**
     * Removes a sub-task from the task.
     *
     * @param subtask  the subtask.
     */
    public void removeSubtask(Task subtask) {
        this.subtasks.remove(subtask);
    }

    /**
     * Returns the sub-task count.
     *
     * @return The sub-task count.
     */
    public int getSubtaskCount() {
        return this.subtasks.size();
    }

    /**
     * Returns a sub-task.
     *
     * @param index  the index.
     *
     * @return The sub-task.
     */
    public Task getSubtask(int index) {
        return (Task) this.subtasks.get(index);
    }
    
    /**
     * Tests this object for equality with an arbitrary object.
     *
     * @param object  the other object (<code>null</code> permitted).
     *
     * @return A boolean.
     */
    public boolean equals(Object object) {
        if (object == this) {
            return true;
        }
        if (!(object instanceof Task)) {
            return false;
        }
        Task that = (Task) object;
        if (!ObjectUtilities.equal(this.description, that.description)) {
            return false;
        }
        if (!ObjectUtilities.equal(this.duration, that.duration)) {
            return false;
        }
        if (!ObjectUtilities.equal(this.percentComplete, 
                that.percentComplete)) {
            return false;
        }
        if (!ObjectUtilities.equal(this.subtasks, that.subtasks)) {
            return false;
        }
        return true;
    }

    /**
     * Returns a clone of the task.
     * 
     * @return A clone.
     * 
     * @throws CloneNotSupportedException  never thrown by this class, but 
     *         subclasses may not support cloning.
     */
    public Object clone() throws CloneNotSupportedException {
        Task clone = (Task) super.clone();
        return clone;      
    }

}
