PHP's interface language and application scenarios

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= specific syntax and characteristics of the interface =//

/*
Specific syntax for the interface:
1, human as a class Human is the sketch of man
And the interface is part
A new species can be combined with a variety of parts.

2, as above, the interface itself is abstract,
The method of internal declaration is also abstract by default.
No need to add abstract

3, a class can implement multiple interfaces at once.
Syntax is implemented with implements
Class Name implements Interface1,interface2,interface3 {

}
Then the function of the interface is implemented.

4, the interface can also inherit, with extends

5, interface is a description of a bunch of methods, can not add attributes

6, the interface is for assembly into class use, the method can only be public
*/

Interface Animal {    //public $age = 2;    Public function Eat ();} Interface Monkey extends Animal {public    function run ();    Public function Cry ();} Interface Wisdom {Public    function think ();} Interface Bird extends Animal {public    function fly (); Class Human implements Monkey,wisdom {public    function eat () {        echo ' eats ';    }    Public Function Run () {        echo ' run ';    }    Public Function Cry () {        echo ' cry ';    }    Public function Think () {        echo ' think ';    }}

= Application scenario of the interface: do an abstract database class =//

/*
Do website
What database do you use?

Can be developed first with MySQL, and then change the database later.

As long as the abstract class development, DB abstract class development.
*/

Abstract class DB {public    abstract function connect ($h, $u, $v, $p);    public abstract function query ($sql);    Public abstract function Close ();}

/*
No matter what database you actually use after you go online
Just write a copy of the following class in DB

The business logic layer does not have to be changed, because it is the implementation of the DB abstract class.
*/

Class Oracle extends DB {}class MSSQL extends DB {}class Postsql extends db {}

The MySQL class required to write exactly corresponds to the DB class Strictly

Class MySQL extends DB {public    function connect ($h, $h, $h, $h) {        return true;    }    Public Function Query ($sql) {    } public    function close () {    }}

= Application scenario of the interface: The Making of social networking sites =//

/*
The processing of users in social networking sites is the core application

Landing
Exit
Write
Read the letter
Say hello
Change mood
Eat
Curse
Trouble
Show Love
Sexy

So many methods are the user's method,
However, analytics users can't use so many methods at once
So we're going to sort them out.

User Information class: (Login, write, read, greet, change mood, exit)
User Entertainment Category: (Login, Curse, trouble, show Love, tease, exit)
*/

Interface UserBase {public    function login ($u, $p);    Public function logout ();} Interface Usermsg {public    function writemsg ($to, $title, $content);    Public Function readmsg ($from, $title);} Interface Userfun {public    function spit ($to);    Public Function Showlove ($to);}

As a caller, I don't need to know your user information class, User entertainment class,
I can know how to call these two classes

Because: all of these two classes implement the above interface
Through this interface, it is possible to standardize development.
*/