/*
 * [HolidaySort.java]
 *
 * Summary: Sort by date holiday occurs in a specified year.
 *
 * Copyright: (c) 2008-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 2008-03-20 initial version
 */
package com.mindprod.holidays;

import java.util.Comparator;

/**
 * Sort by date holiday occurs in a specified year.
 * <p/>
 * Defines an alternate sort order for HolInfo.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 2008-03-20 initial version
 * @since 2008
 */
class HolidaySort implements Comparator<HolInfo>
    {
    /**
     * whether we want dates holiday shifted to
     */
    private final boolean shifted;

    /**
     * year of holidays
     */
    private final int year;

    /**
     * constructor sort holidays in order for a given year.
     *
     * @param year    which year of interest.  Holidays change order in different years.
     * @param shifted true if want to sort by shifted-date you get off work..
     */
    HolidaySort( int year, boolean shifted )
        {
        this.year = year;
        this.shifted = shifted;
        }

    /**
     * Sort by date holiday occurs in a specified year.
     * Defines an alternate sort order for HolInfo.
     * Compare two HolInfo Objects.
     * Informally, returns (a-b), or +ve if a is more positive than b.
     *
     * @param a first HolInfo to compare
     * @param b second HolInfo to compare
     *
     * @return +ve if a&gt;b, 0 if a==b, -ve if a&lt;b
     */
    public final int compare( HolInfo a, HolInfo b )
        {
        return a.when( year, shifted ) - ( b.when( year, shifted ) );
        }
    }