The actual role of php interface class abstract class_PHP tutorial

Many people don’t understand the difference between interfaces and abstract classes! Let me share my understanding with you!

1.php interface class: interface

In fact, their function is very simple. When many people develop a project together, they may all call it Some classes written by others, then you will ask, how do I know how to name the implementation method of a certain function? At this time, the PHP interface class comes into play. When we define an interface class, it The methods inside must be implemented by the following subclasses, such as: Copy to ClipboardQuoted content: [www.bkjia.com] interface Shop
{
public function buy($gid);
public function sell($gid);
public function view($gid);
} I declare a shop interface class and define three methods: buy, sell, and view. Then all subclasses that inherit this class must implement any of these three methods. If the subclass If a class does not implement these words, it cannot run. In fact, the interface class is, to put it bluntly, the template of a class and the regulations of a class. If you belong to this category, you must follow my regulations. No matter how you do it, I don’t care how you do it. That’s up to you. things, such as: Copy to ClipboardQuoted content: [www.bkjia.com] class BaseShop implements Shop
{
public function buy($gid)
{
echo('You purchased the product with ID: '.$gid.');
}
public function sell($gid)
{
echo('You sold the product with ID: '.$gid.');
}
public function view($gid)
{
echo('You viewed the product with ID:'.$gid.');
}
}

Think about it, in a large project where many people collaborate, it is very convenient to have interface classes, so that you don’t have to ask others what the method name of your certain function is. Of course, if you like There's nothing I can do about it.

Conclusion: The interface class is the leader of a class, pointing out the direction, and the subclass must complete its specified method.

2.php abstract class: abstract

In fact, abstract classes and interface classes are partially similar. Remember where I saw this sentence, abstract classes extract the similar parts. This The sentence looks funny, but in fact it tells the truth about abstract classes. The function of abstract classes is that when you find that many of your classes use many methods that you keep repeating, then you can consider using abstract classes. You may say, "Isn't it possible for me to rewrite a class and instantiate each public class and call the same method?" Yes, it is possible. In fact, this is what abstract classes do, but It saves you the step of instantiation, making it as convenient as calling the method of this class directly, and you can also overload this method. Such as:

Copy to ClipboardQuoted content: [www.bkjia.com] abstract class BaseShop
{
public function buy($gid)
{
echo('You purchased the product with ID: '.$gid.');
}
public function sell($gid)
{
echo('You sold the product with the ID: '.$gid.');
}
public function view($gid)
{
echo('You viewed the product with ID: '.$gid.');
}
}
class BallShop extends BaseShop
{
var $ itme_id = null;
public function __construct()
{
$this->itme_id = 2314;
}
public function open()
{
$this- >sell($this->itme_id);
}
}

Here is an example. Like the above, I defined a store class and extracted all its parts, such as buy, sell, and view, and implemented these methods in the abstract class. , then the subclass that inherits it will automatically obtain these methods, and the subclass will do its own unique things, introduce code duplication, and improve reusability.

Conclusion: An abstract class is a service provider of a class. It has many services. You don’t have to use them. You can use them when needed. If you feel dissatisfied with not providing services, you can also use them yourself. Come and do it.

The above are my humble opinions on PHP interface classes and abstract classes. I hope it can help those who are confused about these two. If you have any comments, please leave a message!

Reprinted from: http://www.cnblogs.com/200831856/

http://www.bkjia.com/PHPjc/364422.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/364422.htmlTechArticleMany people don’t understand the difference between interfaces and abstract classes! Let me share my understanding with everyone! 1.php interface class: interface In fact, their role is very simple. When many people develop an...