ComparableList.java

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/*
    Synthia, a data structure generator
    Copyright (C) 2019-2021 Laboratoire d'informatique formelle
    Université du Québec à Chicoutimi, Canada
 
    This program 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 3 of the License, or
    (at your option) any later version.
 
    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 Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package ca.uqac.lif.synthia.collection;
 
import java.util.ArrayList;
import java.util.List;
 
/**
 * Class that extends Java's ArrayList class to implements the Comparable interface.
 *
 * @param <T> The type of the elements of the list.
 * @author Marc-Antoine Plourde
 * @ingroup API
 */
public class ComparableList<T> extends ArrayList<T> implements Comparable<List<T>>
{
    /**
     * Dummy UID.
     */
    private static final long serialVersionUID = 1L;
 
    /**
     * Default constructor.
     */
    public ComparableList()
    {
        super();
    }
 
    /**
     * Constructor who takes a <code>List&lt;T&gt;</code> as parameter.
     *
     * @param l The reference list used to compare to an other list.
     */
    public ComparableList(List<T> l)
    {
        super(l);
    }
 
    /**
     * Public method to compare a list to the reference one.
     *
     * @param o An <code>ArrayList&lt;T&gt;</code> to compare with the reference one.
     * @return <ul>
     *      <li>a negative integer if the reference list is considered smaller than the second one.</li>
     *      <li>0 if the reference list is considered equal to the second one.</li>
     *      <li>A posisitive integer supperior to 0 if the reference list is considered greater than the second one..</li>
     *    <ul/>
     */
    @SuppressWarnings("unchecked")
    @Override public int compareTo(List<T> o)
    {
        if (this.size() < o.size())
        {
            return -1;
        }
        else if (this.size() > o.size())
        {
            return 1;
        }
        else
        {
            int answer = 0;
            int i = 0;
 
            while ((i < this.size()) && (answer == 0))
            {
 
                if (((this.get(i)) instanceof Comparable) && ((o.get(i)) instanceof Comparable))
                {
                    try
                    {
                        answer = ((Comparable<T>) this.get(i)).compareTo(o.get(i));
                    }
                    catch (ClassCastException exception)
                    {
                        answer = 0;
                    }
                }
                else if (((this.get(i)) instanceof List) && ((o.get(i)) instanceof List))
                {
                    answer = new ComparableList<T>((List<T>) this.get(i)).compareTo((ComparableList<T>) o.get(i));
                }
                i++;
            }
            return answer;
        }
    }
}