[英]Chaining Static Methods in PHP?
是否可以使用靜態類將靜態方法鏈接在一起? 假設我想做這樣的事情:
$value = TestClass::toValue(5)::add(3)::subtract(2)::add(8)::result();
. . . 顯然我希望 $value 被分配數字 14。這可能嗎?
更新:它不起作用(你不能返回“自我” - 它不是一個實例!),但這是我的想法帶我去的地方:
class TestClass {
public static $currentValue;
public static function toValue($value) {
self::$currentValue = $value;
}
public static function add($value) {
self::$currentValue = self::$currentValue + $value;
return self;
}
public static function subtract($value) {
self::$currentValue = self::$currentValue - $value;
return self;
}
public static function result() {
return self::$value;
}
}
在解決了這個問題之后,我認為簡單地使用類實例而不是嘗試鏈接靜態函數調用會更有意義(這看起來不可能,除非上面的示例可以以某種方式進行調整)。
我喜歡上面 Camilo 提供的解決方案,本質上是因為您所做的只是更改靜態成員的值,並且由於您確實想要鏈接(即使它只是語法糖),那么實例化 TestClass 可能是最好的方法.
如果您想限制類的實例化,我建議使用單例模式:
class TestClass
{
public static $currentValue;
private static $_instance = null;
private function __construct () { }
public static function getInstance ()
{
if (self::$_instance === null) {
self::$_instance = new self;
}
return self::$_instance;
}
public function toValue($value) {
self::$currentValue = $value;
return $this;
}
public function add($value) {
self::$currentValue = self::$currentValue + $value;
return $this;
}
public function subtract($value) {
self::$currentValue = self::$currentValue - $value;
return $this;
}
public function result() {
return self::$currentValue;
}
}
// Example Usage:
$result = TestClass::getInstance ()
->toValue(5)
->add(3)
->subtract(2)
->add(8)
->result();
class oop{
public static $val;
public static function add($var){
static::$val+=$var;
return new static;
}
public static function sub($var){
static::$val-=$var;
return new static;
}
public static function out(){
return static::$val;
}
public static function init($var){
static::$val=$var;
return new static;
}
}
echo oop::init(5)->add(2)->out();
php5.3 上的小瘋狂代碼......只是為了好玩。
namespace chaining;
class chain
{
static public function one()
{return get_called_class();}
static public function two()
{return get_called_class();}
}
${${${${chain::one()} = chain::two()}::one()}::two()}::one();
使用 php7,您將能夠使用所需的語法,因為新的統一變量語法
<?php
abstract class TestClass {
public static $currentValue;
public static function toValue($value) {
self::$currentValue = $value;
return __CLASS__;
}
public static function add($value) {
self::$currentValue = self::$currentValue + $value;
return __CLASS__;
}
public static function subtract($value) {
self::$currentValue = self::$currentValue - $value;
return __CLASS__;
}
public static function result() {
return self::$currentValue;
}
}
$value = TestClass::toValue(5)::add(3)::subtract(2)::add(8)::result();
echo $value;
如果 toValue(x) 返回一個對象,你可以這樣做:
$value = TestClass::toValue(5)->add(3)->substract(2)->add(8);
提供該 toValue 會返回該對象的一個新實例,並且每個 next 方法都會對其進行變異,返回一個 $this 實例。
這更准確、更容易、更易於閱讀(允許代碼完成)
class Calculator
{
public static $value = 0;
protected static $onlyInstance;
protected function __construct ()
{
// disable creation of public instances
}
protected static function getself()
{
if (static::$onlyInstance === null)
{
static::$onlyInstance = new Calculator;
}
return static::$onlyInstance;
}
/**
* add to value
* @param numeric $num
* @return \Calculator
*/
public static function add($num)
{
static::$value += $num;
return static::getself();
}
/**
* substruct
* @param string $num
* @return \Calculator
*/
public static function subtract($num)
{
static::$value -= $num;
return static::getself();
}
/**
* multiple by
* @param string $num
* @return \Calculator
*/
public static function multiple($num)
{
static::$value *= $num;
return static::getself();
}
/**
* devide by
* @param string $num
* @return \Calculator
*/
public static function devide($num)
{
static::$value /= $num;
return static::getself();
}
public static function result()
{
return static::$value;
}
}
例子:
echo Calculator::add(5)
->subtract(2)
->multiple(2.1)
->devide(10)
->result();
結果:0.63
人們瘋狂地把這件事復雜化了。
看一下這個:
class OopClass
{
public $first;
public $second;
public $third;
public static function make($first)
{
return new OopClass($first);
}
public function __construct($first)
{
$this->first = $first;
}
public function second($second)
{
$this->second = $second;
return $this;
}
public function third($third)
{
$this->third = $third;
return $this;
}
}
用法:
OopClass::make('Hello')->second('To')->third('World');
您始終可以將 First 方法用作靜態方法,將其余方法用作實例方法:
$value = Math::toValue(5)->add(3)->subtract(2)->add(8)->result();
或者更好:
$value = Math::eval(Math::value(5)->add(3)->subtract(2)->add(8));
class Math {
public $operation;
public $operationValue;
public $args;
public $allOperations = array();
public function __construct($aOperation, $aValue, $theArgs)
{
$this->operation = $aOperation;
$this->operationValue = $aValue;
$this->args = $theArgs;
}
public static function eval($math) {
if(strcasecmp(get_class($math), "Math") == 0){
$newValue = $math->operationValue;
foreach ($math->allOperations as $operationKey=>$currentOperation) {
switch($currentOperation->operation){
case "add":
$newvalue = $currentOperation->operationValue + $currentOperation->args;
break;
case "subtract":
$newvalue = $currentOperation->operationValue - $currentOperation->args;
break;
}
}
return $newValue;
}
return null;
}
public function add($number){
$math = new Math("add", null, $number);
$this->allOperations[count($this->allOperations)] &= $math;
return $this;
}
public function subtract($number){
$math = new Math("subtract", null, $number);
$this->allOperations[count($this->allOperations)] &= $math;
return $this;
}
public static function value($number){
return new Math("value", $number, null);
}
}
僅供參考。我在腦海中寫下了這個(就在網站上)。 因此,它可能無法運行,但這就是想法。 我也可以對 eval 進行遞歸方法調用,但我認為這可能更簡單。 如果您希望我詳細說明或提供任何其他幫助,請告訴我。
從技術上講,您可以在 PHP 7+ 中的$object::method()
之類的實例上調用靜態方法,因此返回一個新實例應該可以替代return self
。 確實有效。
final class TestClass {
public static $currentValue;
public static function toValue($value) {
self::$currentValue = $value;
return new static();
}
public static function add($value) {
self::$currentValue = self::$currentValue + $value;
return new static();
}
public static function subtract($value) {
self::$currentValue = self::$currentValue - $value;
return new static();
}
public static function result() {
return self::$currentValue;
}
}
$value = TestClass::toValue(5)::add(3)::subtract(2)::add(8)::result();
var_dump($value);
輸出int(14)
。
這與返回其他答案中使用的__CLASS__
大致相同。 我寧願希望沒有人決定實際使用這些形式的 API,但你要求它。
簡而言之……不。 :) 解析運算符 (::) 將適用於 TetsClass::toValue(5) 部分,但之后的所有內容都只會給出語法錯誤。
一旦在 5.3 中實現了命名空間,您就可以擁有“鏈式”:: 運算符,但所有要做的就是向下鑽取命名空間樹; 在這樣的事情中間不可能有方法。
能做到的最好的
class S
{
public static function __callStatic($name,$args)
{
echo 'called S::'.$name . '( )<p>';
return '_t';
}
}
$_t='S';
${${S::X()}::F()}::C();
不,這行不通。 ::
運算符需要返回一個類,因此在TestClass::toValue(5)
計算之后, ::add(3)
方法只能對最后一個的答案進行計算。
因此,如果toValue(5)
返回整數 5,您基本上會調用int(5)::add(3)
,這顯然是一個錯誤。
我發現從類的新實例或靜態方法鏈接方法的最簡單方法如下。 我在這里使用了后期靜態綁定,我真的很喜歡這個解決方案。
我創建了一個實用程序,可以在 Laravel 中使用 tostr 在下一頁發送多個用戶通知。
<?php
namespace App\Utils;
use Session;
use Illuminate\Support\HtmlString;
class Toaster
{
private static $options = [
"closeButton" => false,
"debug" => false,
"newestOnTop" => false,
"progressBar" => false,
"positionClass" => "toast-top-right",
"preventDuplicates" => false,
"onclick" => null,
"showDuration" => "3000",
"hideDuration" => "1000",
"timeOut" => "5000",
"extendedTimeOut" => "1000",
"showEasing" => "swing",
"hideEasing" => "linear",
"showMethod" => "fadeIn",
"hideMethod" => "fadeOut"
];
private static $toastType = "success";
private static $instance;
private static $title;
private static $message;
private static $toastTypes = ["success", "info", "warning", "error"];
public function __construct($options = [])
{
self::$options = array_merge(self::$options, $options);
}
public static function setOptions(array $options = [])
{
self::$options = array_merge(self::$options, $options);
return self::getInstance();
}
public static function setOption($option, $value)
{
self::$options[$option] = $value;
return self::getInstance();
}
private static function getInstance()
{
if(empty(self::$instance) || self::$instance === null)
{
self::setInstance();
}
return self::$instance;
}
private static function setInstance()
{
self::$instance = new static();
}
public static function __callStatic($method, $args)
{
if(in_array($method, self::$toastTypes))
{
self::$toastType = $method;
return self::getInstance()->initToast($method, $args);
}
throw new \Exception("Ohh my god. That toast doesn't exists.");
}
public function __call($method, $args)
{
return self::__callStatic($method, $args);
}
private function initToast($method, $params=[])
{
if(count($params)==2)
{
self::$title = $params[0];
self::$message = $params[1];
}
elseif(count($params)==1)
{
self::$title = ucfirst($method);
self::$message = $params[0];
}
$toasters = [];
if(Session::has('toasters'))
{
$toasters = Session::get('toasters');
}
$toast = [
"options" => self::$options,
"type" => self::$toastType,
"title" => self::$title,
"message" => self::$message
];
$toasters[] = $toast;
Session::forget('toasters');
Session::put('toasters', $toasters);
return $this;
}
public static function renderToasters()
{
$toasters = Session::get('toasters');
$string = '';
if(!empty($toasters))
{
$string .= '<script type="application/javascript">';
$string .= "$(function() {\n";
foreach ($toasters as $toast)
{
$string .= "\n toastr.options = " . json_encode($toast['options'], JSON_PRETTY_PRINT) . ";";
$string .= "\n toastr['{$toast['type']}']('{$toast['message']}', '{$toast['title']}');";
}
$string .= "\n});";
$string .= '</script>';
}
Session::forget('toasters');
return new HtmlString($string);
}
}
這將如下工作。
Toaster::success("Success Message", "Success Title")
->setOption('showDuration', 5000)
->warning("Warning Message", "Warning Title")
->error("Error Message");
具有靜態屬性的方法鏈接的完整功能示例:
<?php
class Response
{
static protected $headers = [];
static protected $http_code = 200;
static protected $http_code_msg = '';
static protected $instance = NULL;
protected function __construct() { }
static function getInstance(){
if(static::$instance == NULL){
static::$instance = new static();
}
return static::$instance;
}
public function addHeaders(array $headers)
{
static::$headers = $headers;
return static::getInstance();
}
public function addHeader(string $header)
{
static::$headers[] = $header;
return static::getInstance();
}
public function code(int $http_code, string $msg = NULL)
{
static::$http_code_msg = $msg;
static::$http_code = $http_code;
return static::getInstance();
}
public function send($data, int $http_code = NULL){
$http_code = $http_code != NULL ? $http_code : static::$http_code;
if ($http_code != NULL)
header(trim("HTTP/1.0 ".$http_code.' '.static::$http_code_msg));
if (is_array($data) || is_object($data))
$data = json_encode($data);
echo $data;
exit();
}
function sendError(string $msg_error, int $http_code = null){
$this->send(['error' => $msg_error], $http_code);
}
}
使用示例:
Response::getInstance()->code(400)->sendError("Lacks id in request");
這是另一種不通過getInstance
方法的方法(在 PHP 7.x 上測試):
class TestClass
{
private $result = 0;
public function __call($method, $args)
{
return $this->call($method, $args);
}
public static function __callStatic($method, $args)
{
return (new static())->call($method, $args);
}
private function call($method, $args)
{
if (! method_exists($this , '_' . $method)) {
throw new Exception('Call undefined method ' . $method);
}
return $this->{'_' . $method}(...$args);
}
private function _add($num)
{
$this->result += $num;
return $this;
}
private function _subtract($num)
{
$this->result -= $num;
return $this;
}
public function result()
{
return $this->result;
}
}
該類可以如下使用:
$res1 = TestClass::add(5)
->add(3)
->subtract(2)
->add(8)
->result();
echo $res1 . PHP_EOL; // 14
$res2 = TestClass::subtract(1)->add(10)->result();
echo $res2 . PHP_EOL; // 9
也可以作為:
ExampleClass::withBanners()->withoutTranslations()->collection($values)
使用new static(self::class);
public static function withoutTranslations(): self
{
self::$withoutTranslations = true;
return new static(self::class);
}
public static function withBanners(): self
{
return new static(self::class);
}
public static function collection(values): self
{
return $values;
}
使用 PHP 7! 如果您的網絡提供商不能 --> 更改提供商! 不要鎖定過去。
final class TestClass {
public static $currentValue;
public static function toValue($value) {
self::$currentValue = $value;
return __CLASS__;
}
public static function add($value) {
self::$currentValue = self::$currentValue + $value;
return __CLASS__;
}
public static function subtract($value) {
self::$currentValue = self::$currentValue - $value;
return __CLASS__;
}
public static function result() {
return self::$currentValue;
}
}
$value = TestClass::toValue(5)::add(3)::subtract(2)::add(8)::result();
var_dump($value);
返回(或拋出錯誤):
int(14)
完成的合同。
規則一:最進化和可維護的總是更好。
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