PHP5.3_延遲靜態綁定_static

基於PHP版本: 5.3.5

PHP5.3 之後引入了延遲靜態綁定:

static(關鍵字) 相似於 self(關鍵字) , 但它指向的是被調用的類(Document) 而不是包含類(DomainObject) , static 和 self 的區別:

Code:

<?php
class DomainObject{
	public static function createStatic(){
		return new static();		
	}
	public static function createSelf(){
		return new self();
	}
}

class User extends DomainObject{
	
}

class Document extends DomainObject{
	
}

echo '<pre>';
var_dump( Document::createStatic());
var_dump( Document::createSelf());

Result:

object(Document)[1]
object(DomainObject)[1]

 

之前你這麼寫:

abstract class DomainObject{

}

class User extends DomainObject{
	public static function create(){
		return new User();
	}
}

class Document extends DomainObject{
	public static function create(){
		return new Document();
	}
}

如今, 你能夠這麼寫: 

abstract class DomainObject{
	public static function create(){
		return new static();
	}
}

class User extends DomainObject{

}

class Document extends DomainObject{

}

好處: 能夠節省大量重複代碼~