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PHP - Manual: forward_static_call

2024-12-21

forward_static_call

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

forward_static_callCall a static method

说明

forward_static_call(callable $function, mixed $parameter = ?, mixed $... = ?): mixed

Calls a user defined function or method given by the function parameter, with the following arguments. This function must be called within a method context, it can't be used outside a class. It uses the late static binding.

参数

function

The function or method to be called. This parameter may be an array, with the name of the class, and the method, or a string, with a function name.

parameter

Zero or more parameters to be passed to the function.

返回值

Returns the function result, or false on error.

范例

示例 #1 forward_static_call() example

<?php

class A
{
    const 
NAME 'A';
    public static function 
test() {
        
$args func_get_args();
        echo static::
NAME" ".join(','$args)." \n";
    }
}

class 
extends A
{
    const 
NAME 'B';

    public static function 
test() {
        echo 
self::NAME"\n";
        
forward_static_call(array('A''test'), 'more''args');
        
forward_static_call'test''other''args');
    }
}

B::test('foo');

function 
test() {
        
$args func_get_args();
        echo 
"C ".join(','$args)." \n";
    }

?>

以上例程会输出:

B
B more,args 
C other,args

参见

add a noteadd a note

User Contributed Notes 2 notes

up
2
arthur dot techarts at gmail dot com
10 years ago
Example to understand this function and difference with call_user_func:

<?php
class Beer {
    const
NAME = 'Beer!';
    public static function
printed(){
        echo
'static Beer:NAME = '. static::NAME . PHP_EOL;
    }
}

class
Ale extends Beer {
    const
NAME = 'Ale!';
    public static function
printed(){
       
forward_static_call(array('parent','printed'));
       
call_user_func(array('parent','printed'));

       
forward_static_call(array('Beer','printed'));
       
call_user_func(array('Beer','printed'));
    }
}

Ale::printed();
echo
'</pre>';
?>
up
0
jhibbard at gmail dot com
10 years ago
Example usage via calls outside of the class and within an object:

<?php
/**
* @author Jonathon Hibbard
*/
class foo {
 
# used to verify we're actually setting something..
 
private static $value = '';

 
/**
   * Simple setter for the static method setValue...
   */
 
public static function set($method_identifier, $value_to_pass = '') {
   
# make sure we have the right method format...
    # another semi-useful example is like this (useful for REST-like requests...): str_replace(" ", "", ucwords(str_replace("_", " ",  $method_identifier)));
   
$static_method = 'set' . ucfirst(strtolower(trim($method_identifier)));

    if(
method_exists(__CLASS__, $static_method)) {
     
//Note:  this will not work and will throw PHP Parse error:  syntax error, unexpected '::'
      //__CLASS__::$static_method($value_to_pass);

     
foo::$static_method($value_to_pass);

      echo
"\tCalling forward_static_call with pure string and value param:\n";
     
forward_static_call(__CLASS__ . "::" . $static_method, $value_to_pass);

      echo
"\tCalling forward_static_call with class, method array and value param:\n";
     
forward_static_call(array(__CLASS__, $static_method), $value_to_pass);
    }
  }

 
/**
   * Set self::$value to something?
   */
 
public static function setValue($value_recieved = '') {
    echo
"\t\tsetValue called with param of " . var_export($value_recieved, true) . "!\n";

    echo
"\t\tSetting Private 'value'...\n";

   
self::$value = $value_recieved;

    echo
"\t\tChecking the Private 'value':\n";
    if(!empty(
self::$value)) {
      echo
"\t\t\tPrivate 'value' was set to '" . self::$value . "' as expected!\n";
    } else {
      echo
"\t\t\tPrivate 'value' was not set!\n";
    }

   
# Reset...
   
self::$value = '';
  }

 
/**
   * Create an object and test calling the static method from within this realm...
   */
 
public function __construct() {
    echo
"\tCalling from within constructor..\n";
   
foo::set('value','Something else from within the instance!');
  }
}

echo
"\n============ Calling by static method first ============\n";
foo::set('value','Something from outside of the foo class!');

echo
"\n============ Calling by static method without a value next ============\n";
foo::set('value');

echo
"\n============ Calling by createing an instance next ============\n";
new
foo();
?>

官方地址:https://www.php.net/manual/en/function.forward-static-call.php

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