PHP的Enum（枚举）的实现，phpenum枚举实现-php手册-PHP中文网

PHP的Enum（枚举）的实现，phpenum枚举实现

php中文网

发布： 2016-06-13 08:49:42

原创

2238人浏览过

php的enum（枚举）的实现，phpenum枚举实现

php其实有enum类库的，需要安装perl扩展，所以不是php的标准扩展，因此代码的实现需要运行的php环境支持。

（1）扩展类库SplEnum类。该类的摘要如下：

1 2 3 4 5 6 7 8

SplEnum extends SplType { /* Constants */ const NULL __default = null ; /* 方法 */ public array getConstList ([ bool $include_default = false ] ) /* 继承的方法 */ SplType::__construct ([ mixed $initial_value [, bool $strict ]] ) }

使用示例：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

getMessage() . PHP_EOL; } ?>

　输出结果：

1 2	6 Value not a const in enum Month

立即学习“PHP免费学习笔记（深入）”；

（2）自定义的Enum类库

摘自http://www.php4every1.com/scripts/php-enum/

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115

self::__default )) : self::$constants[__CLASS_]; } /** * Creates new enum object. If child class overrides __construct(), * it is required to call parent::__construct() in order for this * class to work as expected. * * @param mixed $initialValue Any value that is exists in defined constants * @param bool $strict If set to true, type and value must be equal * @throws UnexpectedValueException If value is not valid enum value */ public function __construct($initialValue = null, $strict = true) { $class = get_class($this); if (!array_key_exists($class, self::$constants)) { self::populateConstants(); } if ($initialValue === null) { $initialValue = self::$constants[$class]["__default"]; } $temp = self::$constants[$class]; if (!in_array($initialValue, $temp, $strict)) { throw new UnexpectedValueException("Value is not in enum " . $class); } $this->value = $initialValue; $this->strict = $strict; } private function populateConstants() { $class = get_class($this); $r = new ReflectionClass($class); $constants = $r->getConstants(); self::$constants = array( $class => $constants ); } /** * Returns string representation of an enum. Defaults to * value casted to string. * * @return string String representation of this enum's value */ public function __toString() { return (string) $this->value; } /** * Checks if two enums are equal. Only value is checked, not class type also. * If enum was created with $strict = true, then strict comparison applies * here also. * * @return bool True if enums are equal */ public function equals($object) { if (!($object instanceof Enum)) { return false; } return $this->strict ? ($this->value === $object->value) : ($this->value == $object->value); } }

使用示例如下：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

class MyEnum extends Enum { const HI = "Hi"; const BY = "By"; const NUMBER = 1; const __default = self::BY; } var_dump(new MyEnum(MyEnum::HI)); var_dump(new MyEnum(MyEnum::BY)); //Use __default var_dump(new MyEnum()); try { new MyEnum("I don't exist"); } catch (UnexpectedValueException $e) { var_dump($e->getMessage()); }

输出结果如下：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

object(MyEnum)#1 (2) { ["value":"Enum":private]=> string(2) "Hi" ["strict":"Enum":private]=> bool(true) } object(MyEnum)#1 (2) { ["value":"Enum":private]=> string(2) "By" ["strict":"Enum":private]=> bool(true) } object(MyEnum)#1 (2) { ["value":"Enum":private]=> string(2) "By" ["strict":"Enum":private]=> bool(true) } string(27) "Value is not in enum MyEnum"