iterator.ats

import { Logger } from '../logger';

export class Aggregate {
    constructor() {
        this.items = [];
    }

    get Count() {
        return this.items.length;
    }

}
//Abstract class
export class Iterator {
    firstObject():any {
        throw new Error("Abstract method!");
    }

    nextObject():any {
        throw new Error("Abstract method!");
    }

    currentObject():any {
        throw new Error("Abstract method!");
    }

    isDone():boolean {
        throw new Error("Abstract method!");
    }
}
//Concrete of Iterator
export class ConcreteIterator extends Iterator {

    constructor(aggregate:Aggregate) {
        this._aggregate = aggregate;
        this._items = this._aggregate.items;
        this.index = 0;
    }

    firstObject():any {
        return this._items[0];
    }

    nextObject():any {
        var retVal = null;
        if (this.index < (this._aggregate.Count - 1))
            retVal = this._items[++this.index];
        else
            retVal = "There is no more item in the list!";
        return retVal;
    }

    isDone():boolean {
        return this.index >= (this._aggregate.Count - 1);
    }

    currentObject() {
        return this._items[this.index];
    }
}