Calendar.js

/*
 * Calendar.js - Represent a calendar object.
 *
 * Copyright © 2012-2015, 2023 JEDLSoft
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @class
 * Superclass for all calendar subclasses that contains shared
 * functionality.  
 * This class is never instantiated on its own. Instead,
 * you should use the {@link CalendarFactory} function to manufacture a new
 * instance of a subclass of Calendar.
 *
 * @protected
 * @constructor
 */
var Calendar = function() {
};

/* place for the subclasses to put their constructors so that the factory method
 * can find them. Do this to add your calendar after it's defined:
 * Calendar._constructors["mytype"] = Calendar.MyTypeConstructor;
 */
Calendar._constructors = {};

Calendar.prototype = {
    /**
     * Return the type of this calendar.
     *
     * @return {string} the name of the type of this calendar
     */
    getType: function() {
        throw "Cannot call methods of abstract class Calendar";
    },

    /**
     * Return the number of months in the given year. The number of months in a year varies
     * for some luni-solar calendars because in some years, an extra month is needed to extend the
     * days in a year to an entire solar year. The month is represented as a 1-based number
     * where 1=first month, 2=second month, etc.
     *
     * @param {number} year a year for which the number of months is sought
     * @return {number} The number of months in the given year
     */
    getNumMonths: function(year) {
        throw "Cannot call methods of abstract class Calendar";
    },

    /**
     * Return the number of days in a particular month in a particular year. This function
     * can return a different number for a month depending on the year because of things
     * like leap years.
     *
     * @param {number} month the month for which the length is sought
     * @param {number} year the year within which that month can be found
     * @return {number} the number of days within the given month in the given year
     */
    getMonLength: function(month, year) {
        throw "Cannot call methods of abstract class Calendar";
    },

    /**
     * Return true if the given year is a leap year in this calendar.
     * The year parameter may be given as a number.
     *
     * @param {number} year the year for which the leap year information is being sought
     * @return {boolean} true if the given year is a leap year
     */
    isLeapYear: function(year) {
        throw "Cannot call methods of abstract class Calendar";
    }
};

module.exports = Calendar;