Abstract Factory:Provide an interface for creating families of related or dependent objects without specifying their concrete classes.

抽象工廠(Abstract Factory)模式是所有工廠模式中最抽象和最具有一般性的形態，和工廠方法模式的最大區別在於，工廠方法模式針對的是一個產品等級結構，而抽象工廠模式則需要對多個產品等級結構。

一：引入

         最早起源應用於不通作業系統的視窗構件，如一個Button類在windows環境和unix環境下有對應的實現，如果使用工廠方法模式，需要每個Concrete Product類對應一個Concrete Factory，在太多構件的情況下顯然不合適。

         改為有兩個Concrete Factory(因為有兩大類(當然也可以有多個類)),每個Factory類負責建立這一類的所有物件。

publicclass WinFactory implements AbstractFactory...{
    public Button createButton()
    ...{
        returnnew WinButton();
    }
    public Text createText()
    ...{
        returnnew WinText();
    }
}

publicclass UnixFactory implements AbstractFactory...{
    public Button createButton()
    ...{
        returnnew UnixButton();
    }
    public Text createText()
    ...{
        returnnew UnixText();
    }
}

二：結構

三：實際應用

1. 最早起源應用於不通作業系統的視窗構件。

四：適用情形

Use the Abstract Factory pattern when

a system should be independent of how its products are created, composed, and represented. a system should be configured with one of multiple families of products. a family of related product objects is designed to be used together, and you need to enforce this constraint. you want to provide a class library of products, and you want to reveal just their interfaces, not their implementations.

參考文獻：

1:閻巨集，《Java與模式》，電子工業出版社
2:Eric Freeman & Elisabeth Freeman，《Head First Design Pattern》，O'REILLY