PHP singleton mode and Factory mode

One, single case mode

A class can only instantiate one object

Class Ren
{
private static $DX; used to store generated objects, static methods call static members
Public $name;

Private Constructors
Private Function __construct ()
{

}
methods for generating objects
public static function Duixiang ()
{
if (Empty (self:: $DX))// determines if NULL, if NULL, new object
{
Self:: $DX = new Ren ();
}

Return self:: $DX;
}
}

$r = Ren::D Uixiang ();
$r->name = "Zhang San";

$r 1 = Ren::D Uixiang ();

Var_dump ($r 1);

Second, the factory model

The first way: not High Security

Class Suan

{

public $a;

Public $b;

function Jia ()

{

return $this->a+ $this->b;

}

Function Jian ()

{

return $this->a-$this->b;

}

}

$s =new Suan ();

$s->a=10;

$s->b=5;

echo $s->jia ();

The second way: scalability is strong

Class Yunsuan

{

public $a;

Public $b;

function Suan ()

{

}

}

Class Jia extends Yunsuan

{

function Suan ()

{

return $this->a+ $this->b;

}

}

Class Jian extends Yunsuan

{

function Suan ()

{

return $this->a-$this->b;

}

}

$s = new Jia ();

$s->a=10;

$s->b=5;

echo $s->suan ();

　The Third Way: Factory mode

Objective: The disadvantage of solving the second approach: when there are many subclasses, the method name may be heavy, and thus different objects can be determined by different operators

Class Yunsuan

{

public $a;

Public $b;

function Suan ()

{

}

}

Class Jia extends Yunsuan

{

function Suan ()

{

return $this->a+ $this->b;

}

}

Class Jian extends Yunsuan

{

function Suan ()

{

return $this->a-$this->b;

}

}//To this end is the same as the second way; The purpose is to solve when there are many subclasses, the method name may be heavy, so that different classes can be determined by different operators

Class Gongchang

{

static function Shengchan ($f)

{

Switch ($f)

{

Case "+":

return new Jia ();

Break

Case "-":

return new Jian ();

Break

}

}

}

$r = Gongchang::shengchan ("-");

$r->a=10;

$r->b=5;

echo $r->suan ();

　　

PHP singleton mode and Factory mode