forward_static_call()

(PHP 5 >= 5.3.0, PHP 7)

Call a static method

说明

forward_static_call(callable $function[,mixed $parameter[,mixed$...]]): mixed

Calls a user defined function or method given by the$functionparameter, with the following arguments. This function must be called within a method context, it can't be used outside a class. It uses thelate 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,orFALSEon error.

范例

Example #1forward_static_call()example

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

forward_static_call_array()Call a static method and pass the arguments as array
call_user_func_array() 调用回调函数，并把一个数组参数作为回调函数的参数
call_user_func() 把第一个参数作为回调函数调用
is_callable() 检测参数是否为合法的可调用结构
callback类型的信息

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>';
?>

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();
?>