/**
 * Licensed under the Artistic License; you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://displaytag.sourceforge.net/license.html
 *
 * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */
package org.displaytag.model;

import org.displaytag.exception.SortComparatorInstantiationException;
import org.displaytag.util.ReflectHelper;

import java.util.Comparator;
import java.util.ArrayList;


/**
 * Factory for RowSort Comparator object.
 * @author Fabrizio Giustina
 * @version $Revision: 1 $ ($Author: Chidambaram_pl $)
 */
public final class SortComparatorFactory
{

    /**
     * Constructor for SortComparatorFactory.
     */
    private SortComparatorFactory()
    {
        // unused
    }

    /**
     * If the user has specified a sortComparator, then this method takes care of creating the SortComparator (and checking to
     * make sure it is a subclass of the java.util.Comparator object). If there are any problems loading the SortComparator then
     * this will throw a SortComparatorInstantiationException which will get propagated up to the page.
     * @param sortComparatorName String full sortComparator class name
     * @return instance of Comparator
     * @throws SortComparatorInstantiationException if unable to load specified Comparator
     */
    public static Comparator loadSortComparator(String sortComparatorName, Class[] parameterTypes, Object[] parameterValues) throws SortComparatorInstantiationException
    {
        if (sortComparatorName == null || sortComparatorName.length() == 0)
        {
            //return null;
            // If no sort comparator is provided, then use the default RowSort comparator
            sortComparatorName = "org.displaytag.model.RowSorter";
        }

        Comparator comparator = null;
        try
        {
            Class sortComparatorClass = ReflectHelper.classForName(sortComparatorName);
            if (parameterTypes != null && parameterTypes.length > 0) {
                java.lang.reflect.Constructor constructor = sortComparatorClass.getConstructor(parameterTypes);
                comparator = (Comparator) constructor.newInstance(parameterValues);
            } else {
                comparator = (Comparator) sortComparatorClass.newInstance();
            }
            return comparator;
        }
        catch (ClassNotFoundException e)
        {
            throw new SortComparatorInstantiationException(SortComparatorFactory.class, sortComparatorName, e);
        }
        catch (InstantiationException e)
        {
            throw new SortComparatorInstantiationException(SortComparatorFactory.class, sortComparatorName, e);
        }
        catch (IllegalAccessException e)
        {
            throw new SortComparatorInstantiationException(SortComparatorFactory.class, sortComparatorName, e);
        }
        catch (ClassCastException e)
        {
            throw new SortComparatorInstantiationException(SortComparatorFactory.class, sortComparatorName, e);
        }
        catch (IllegalArgumentException e)
        {
            throw new SortComparatorInstantiationException(SortComparatorFactory.class, sortComparatorName, e);
        }
        catch (NoSuchMethodException e)
        {
            throw new SortComparatorInstantiationException(SortComparatorFactory.class, sortComparatorName, e);
        }
        catch (java.lang.reflect.InvocationTargetException e)
        {
            throw new SortComparatorInstantiationException(SortComparatorFactory.class, sortComparatorName, e);
        }
    }

}