Introduction to the abstract factory model of JavaScript design patterns _javascript Skills

Abstract Factory mode Description

1. The problem of the factory method pattern: In the factory method pattern, the creation class all needs to go through the factory class, if wants to extend the program, must modify the factory class, this violates the closure principle, to expands opens, to the modification closes, has the certain question to the design.
2. How to solve: the use of abstract Factory mode, is the function of the class to create a separate factory class, so you do not have to modify the previous code, but also extended the functionality.
3. The factory model is in fact the implementation of the same interface to implement the unified factory way to create the call, but JavaScript does not have the interface of this thing, so remove this layer implementation, but a bit functional class members and methods should be the same;

Abstract Factory Source code example

1. Mail Delivery class:

Copy Code code as follows:

function MailSender () {
this.to = ';
This.title = ';
This.content = ';
}

MailSender.prototype.send = function () {
Send Body
}

2. SMS Send class:

Copy Code code as follows:

function Smssender () {
this.to = ';
This.title = ';
This.content = ';
}

SmsSender.prototype.send = function () {
Send Body
}

3. Here is the creation of factory interface class, here is removed; Directly create various functional plant;

1>. Mail Factory class:

Copy Code code as follows:

function Mailfactory () {

}
MailFactory.prototype.produce = function () {
return new MailSender ();
}

2>. SMS Factory class:

Copy Code code as follows:

function SMSfactory () {

}
SmsFactory.prototype.produce = function () {
return new Smssender ();
}

4. How to use:

Copy Code code as follows:

var factory = new Mailfactory ();
var sender = Factory.produce ();
sender.to = ' toname#mail.com ';
Sender.title = ' abstract factory model ';
sender.content = ' send content ';
Sender.send ();

Other Notes

In object-oriented languages such as Java,.net C # used in the factory model, are used to interface, interface is exposed to various users of the available methods to explain the function of what the application of the method, how the user should use this interface. Objects in the form of classes, representing some kind of abstraction in the real world, perhaps the scene will have a lot of similar applications, such as the above mail send, send text messages, and then such as shopping malls in a variety of promotional means, as well as the animal world of all kinds of birds and beasts.

If we do not provide user access in the form of interfaces, it is bound to provide the user with the real function of exposing the object, and the user can modify and extend the class object at will, which is not allowed.

The factory method pattern and the abstract factory pattern can solve the problem very well, the user can only use the interface to invoke the factory class to carry out the prescribed operation; the abstract factory pattern makes it easier to use the extension function, and the functional class and the factory class implement the respective class-level extensions on the corresponding interface. Does not involve modification to other classes or methods;

Of course JavaScript this language, no way to do so, programmers have self-discipline!