我知道PHP还没有本地枚举。但是我已经习惯了来自Java世界的它们。我喜欢使用枚举来提供ide的自动补全功能能够理解的预定义值。
常量可以解决这个问题,但是存在名称空间冲突问题,而且(实际上是因为)它们是全局的。数组没有名称空间的问题,但是它们太模糊了,它们可以在运行时被覆盖,而且ide很少知道如何在没有额外的静态分析注释或属性的情况下自动填充它们的键。
你有什么常用的解决方案/变通办法吗?有人记得PHP的人对枚举有什么想法或决定吗?
我知道PHP还没有本地枚举。但是我已经习惯了来自Java世界的它们。我喜欢使用枚举来提供ide的自动补全功能能够理解的预定义值。
常量可以解决这个问题,但是存在名称空间冲突问题,而且(实际上是因为)它们是全局的。数组没有名称空间的问题,但是它们太模糊了,它们可以在运行时被覆盖,而且ide很少知道如何在没有额外的静态分析注释或属性的情况下自动填充它们的键。
你有什么常用的解决方案/变通办法吗?有人记得PHP的人对枚举有什么想法或决定吗?
当前回答
这是我对“动态”enum的看法…这样我就可以用变量来调用它,比如从表单中。
看看这个代码块下面的更新版本…
$value = "concert";
$Enumvalue = EnumCategory::enum($value);
//$EnumValue = 1
class EnumCategory{
const concert = 1;
const festival = 2;
const sport = 3;
const nightlife = 4;
const theatre = 5;
const musical = 6;
const cinema = 7;
const charity = 8;
const museum = 9;
const other = 10;
public function enum($string){
return constant('EnumCategory::'.$string);
}
}
更新:更好的方式做…
class EnumCategory {
static $concert = 1;
static $festival = 2;
static $sport = 3;
static $nightlife = 4;
static $theatre = 5;
static $musical = 6;
static $cinema = 7;
static $charity = 8;
static $museum = 9;
static $other = 10;
}
电话
EnumCategory::${$category};
其他回答
好吧,对于一个简单的java,比如php中的enum,我使用:
class SomeTypeName {
private static $enum = array(1 => "Read", 2 => "Write");
public function toOrdinal($name) {
return array_search($name, self::$enum);
}
public function toString($ordinal) {
return self::$enum[$ordinal];
}
}
我们称它为:
SomeTypeName::toOrdinal("Read");
SomeTypeName::toString(1);
但我是PHP初学者,语法不好,所以这可能不是最好的方法。我尝试了一些类常量,使用反射从它的值中获得常量名,可能更整洁。
基于此要点,所有枚举的基类:
abstract class Enum {
protected $val;
protected function __construct($arg) {
$this->val = $arg;
}
public function __toString() {
return $this->val;
}
public function __set($arg1, $arg2) {
throw new Exception("enum does not have property");
}
public function __get($arg1) {
throw new Exception("enum does not have property");
}
// not really needed
public function __call($arg1, $arg2) {
throw new Exception("enum does not have method");
}
// not really needed
static public function __callStatic($arg1, $arg2) {
throw new Exception("enum does not have static method");
}
}
你的枚举:
final class MyEnum extends Enum {
static public function val1() {
return new self("val1");
}
static public function val2() {
return new self("val2");
}
static public function val3() {
return new self("val3");
}
}
测试:
$a = MyEnum::val1();
echo "1.the enum value is '$a'\n";
function consumeMyEnum(MyEnum $arg) {
return "2.the return value is '$arg'\n";
}
echo consumeMyEnum($a);
$version = explode(".", PHP_VERSION);
if ($version[0] >= 7) {
try {
echo consumeMyEnum("val1");
} catch (TypeError $e) {
echo "3.passing argument error happens (PHP 7.0 and above)\n";
}
}
echo ($a == MyEnum::val1()) ? "4.same\n" : "4.different\n";
echo ($a == MyEnum::val2()) ? "5.same\n" : "5.different\n";
$b = MyEnum::val1();
echo ($a == $b) ? "6.same\n" : "6.different\n";
echo ($a === $b) ? "7.same\n" : "7.different\n";
$c = MyEnum::val2();
echo ($a == $c) ? "8.same\n" : "8.different\n";
echo ($a === $c) ? "9.same\n" : "9.different\n";
switch ($c) {
case MyEnum::val1(): echo "10.case of 1st\n"; break;
case MyEnum::val2(): echo "11.case of 2nd\n"; break;
case MyEnum::val3(): echo "12.case of 3rd\n"; break;
}
try {
$a->prop = 10;
} catch (Exception $e) {
echo "13.set property error happens\n";
}
try {
echo $a->prop;
} catch (Exception $e) {
echo "14.get property error happens\n";
}
try {
echo $a->meth();
} catch (Exception $e) {
echo "15.method call error happens\n";
}
try {
echo MyEnum::meth();
} catch (Exception $e) {
echo "16.static method call error happens\n";
}
class Ordinary {}
echo $a instanceof MyEnum ? "17.MyEnum instance\n" : "17.not MyEnum instance\n";
echo $a instanceof Enum ? "18.Enum instance\n" : "18.not Enum instance\n";
echo $a instanceof Ordinary ? "19.Ordinary instance\n" : "19.not Ordinary instance\n";
在网上试试:沙盒
另一种方法是使用神奇的__set方法并将枚举设为私有。
e.g.
class Human{
private $gender;
public function __set($key, $value){
if($key == 'day' && !in_array($value, array('Man', 'Woman')){
new Exception('Wrong value for '.__CLASS__.'->'.$key);
}
else{
$this->$key = $value;
}
...
}
}
每当类本身之外的代码试图设置类属性时,就会调用这个神奇的方法。 这是从PHP5 - 8工作。
class DayOfWeek {
static $values = array(
self::MONDAY,
self::TUESDAY,
// ...
);
const MONDAY = 0;
const TUESDAY = 1;
// ...
}
$today = DayOfWeek::MONDAY;
// If you want to check if a value is valid
assert( in_array( $today, DayOfWeek::$values ) );
不要使用反射。这使得你很难推断你的代码并追踪某些东西被使用的位置,而且往往会破坏静态分析工具(例如你的IDE中内置的工具)。
昨天我在博客上写了这门课。我认为在php脚本中使用它可能很容易:
final class EnumException extends Exception{}
abstract class Enum
{
/**
* @var array ReflectionClass
*/
protected static $reflectorInstances = array();
/**
* Массив конфигурированного объекта-константы enum
* @var array
*/
protected static $enumInstances = array();
/**
* Массив соответствий значение->ключ используется для проверки -
* если ли константа с таким значением
* @var array
*/
protected static $foundNameValueLink = array();
protected $constName;
protected $constValue;
/**
* Реализует паттерн "Одиночка"
* Возвращает объект константы, но но как объект его использовать не стоит,
* т.к. для него реализован "волшебный метод" __toString()
* Это должно использоваться только для типизачии его как параметра
* @paradm Node
*/
final public static function get($value)
{
// Это остается здесь для увеличения производительности (по замерам ~10%)
$name = self::getName($value);
if ($name === false)
throw new EnumException("Неизвестая константа");
$className = get_called_class();
if (!isset(self::$enumInstances[$className][$name]))
{
$value = constant($className.'::'.$name);
self::$enumInstances[$className][$name] = new $className($name, $value);
}
return self::$enumInstances[$className][$name];
}
/**
* Возвращает массив констант пар ключ-значение всего перечисления
* @return array
*/
final public static function toArray()
{
$classConstantsArray = self::getReflectorInstance()->getConstants();
foreach ($classConstantsArray as $k => $v)
$classConstantsArray[$k] = (string)$v;
return $classConstantsArray;
}
/**
* Для последующего использования в toArray для получения массива констант ключ->значение
* @return ReflectionClass
*/
final private static function getReflectorInstance()
{
$className = get_called_class();
if (!isset(self::$reflectorInstances[$className]))
{
self::$reflectorInstances[$className] = new ReflectionClass($className);
}
return self::$reflectorInstances[$className];
}
/**
* Получает имя константы по её значению
* @param string $value
*/
final public static function getName($value)
{
$className = (string)get_called_class();
$value = (string)$value;
if (!isset(self::$foundNameValueLink[$className][$value]))
{
$constantName = array_search($value, self::toArray(), true);
self::$foundNameValueLink[$className][$value] = $constantName;
}
return self::$foundNameValueLink[$className][$value];
}
/**
* Используется ли такое имя константы в перечислении
* @param string $name
*/
final public static function isExistName($name)
{
$constArray = self::toArray();
return isset($constArray[$name]);
}
/**
* Используется ли такое значение константы в перечислении
* @param string $value
*/
final public static function isExistValue($value)
{
return self::getName($value) === false ? false : true;
}
final private function __clone(){}
final private function __construct($name, $value)
{
$this->constName = $name;
$this->constValue = $value;
}
final public function __toString()
{
return (string)$this->constValue;
}
}
用法:
class enumWorkType extends Enum
{
const FULL = 0;
const SHORT = 1;
}