팩토리 메소드 (factory method) 패턴

Posted on Edited on In , Word count in article: 163 Reading time ≈ 1 mins.

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객체 생성에 관련된 패턴입니다.
객체를 생성하기 위한 인터페이스를 정의하고, 인스턴스 생성은 서브클래스가 결정하게 한다

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샘플 코드

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function Factory() {
    this.createEmployee = function (type) {
        var employee;
 
        if (type === "fulltime") {
            employee = new FullTime();
        } else if (type === "parttime") {
            employee = new PartTime();
        } else if (type === "temporary") {
            employee = new Temporary();
        } else if (type === "contractor") {
            employee = new Contractor();
        }
 
        employee.type = type;
 
        employee.say = function () {
            log.add(this.type + ": rate " + this.hourly + "/hour");
        }
 
        return employee;
    }
}
 
var FullTime = function () {
    this.hourly = "$12";
};
 
var PartTime = function () {
    this.hourly = "$11";
};
 
var Temporary = function () {
    this.hourly = "$10";
};
 
var Contractor = function () {
    this.hourly = "$15";
};
 
// log helper
var log = (function () {
    var log = "";
 
    return {
        add: function (msg) { log += msg + "\n"; },
        show: function () { alert(log); log = ""; }
    }
})();
 
function run() {
    var employees = [];
    var factory = new Factory();
 
    employees.push(factory.createEmployee("fulltime"));
    employees.push(factory.createEmployee("parttime"));
    employees.push(factory.createEmployee("temporary"));
    employees.push(factory.createEmployee("contractor"));
    
    for (var i = 0, len = employees.length; i < len; i++) {
        employees[i].say();
    }
 
    log.show();
}