File : data/CollectionIterator.js

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/*
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Copyright - 2017 2023 - wwwouaiebe - Contact: https://www.ouaie.be/
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This  program is free software;
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you can redistribute it and/or modify it under the terms of the
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GNU General Public License as published by the Free Software Foundation;
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either version 3 of the License, or any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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*/
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/*
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Changes:
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    - v4.0.0:
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        - created from v3.6.0
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Doc reviewed 202208
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 */
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import { ZERO, ONE, NOT_FOUND } from '../main/Constants.js';
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/* ------------------------------------------------------------------------------------------------------------------------- */
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/**
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iterator for Collection class
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*/
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/* ------------------------------------------------------------------------------------------------------------------------- */
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class CollectionIterator {
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    /**
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    The collection used by the iterator
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    @type {Collection}
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    */
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    #collection = null;
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    /**
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    The current index
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    @type {Number}
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    */
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    #index = NOT_FOUND;
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    /**
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    The constructor
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    @param {Collection} collection The collection for witch the iterator is used
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    */
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    constructor ( collection ) {
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        Object.freeze ( this );
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        this.#collection = collection;
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    }
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    /**
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    The object pointed by the iterator
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    @type {TravelObject}
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    */
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    get value ( ) { return this.#index < this.#collection.length ? this.#collection.at ( this.#index ) : null; }
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    /**
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    The object before the object pointed by the iterator or null if iterator is on the first object
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    @type {TravelObject}
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    */
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    get previous ( ) { return ZERO >= this.#index ? null : this.#collection.at ( this.#index - ONE ); }
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    /**
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    The object after the object pointed by the iterator or null if iterator is on the last object
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    @type {TravelObject}
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    */
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    get next ( ) { return this.#index < this.#collection.length - ONE ? this.#collection.at ( this.#index + ONE ) : null; }
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    /**
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    Move the iterator to the next object and return true when the end of the Collection is reached
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    @type {Boolean}
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    */
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    get done ( ) { return ++ this.#index >= this.#collection.length; }
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    /**
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    returns true when the iterator is on the first object
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    @type {Boolean}
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    */
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    get first ( ) { return ZERO === this.#index; }
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    /**
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    returns true when the iterator is on the last object
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    @type {Boolean}
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    */
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    get last ( ) { return this.#index >= this.#collection.length - ONE; }
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    /**
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    returns The position of the iterator in the Collection
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    @type {Number}
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    */
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    get index ( ) { return this.#index; }
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}
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export default CollectionIterator;
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/* --- End of file --------------------------------------------------------------------------------------------------------- */
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