PHP Classes

Typesafe Enum: Implement enumerated values as class functions

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typesafe-enum 1.1BSD License5.2.5PHP 5, Data types, Code Generation
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This class can be used to implement enumerated values as class functions.

It takes the name of a class and the list of names for enumerated values to define and generates code for a new class that defines the enumerated values.

The enumerated values can be retrieved using static function calls to the generated class.

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Enumerated values can be used to assign meaningful values to variables that only accept a limited number of values.

An alternative way to implement enumerated value types by using class functions to represent each enumerated value.

Manuel Lemos
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+-----------------------------------------------------------------------------+ | Typesafe Enum | +-----------------------------------------------------------------------------+ - Synopsis - Requirements - Files - Simple Usage: Generation - Extended Usage: Methods - Extended Usage: Configuration - Extended Usage: Manual Definition - Performance Synopsis -------- This package is an implementation of the Typesafe Enum Pattern known from JAVA before it had its own Enum type. The Enum class can be used as base class to implement typesafe enumerations easily in PHP and also to generate them automatically. If you are not familiar with the pattern, I recommend reading this explanation of the JAVA pattern: http://java.sun.com/developer/Books/shiftintojava/page1.html#replaceenums Requirements ------------ The package requires PHP 5.2.6 or later. It depends on the following functionality from PHP > 5.0: 5.2.5: debug_backtrace() parameter in Enum::define() and Enum::___get() 5.2.0: recursive mkdir in Enum::___writeToCache() 5.1.0: InvalidArgumentException from SPL in Enum::define() and Enum::valuesOf() 5.1.0: LOCK_EX flag in Enum::___writeToCache() 5.1.0: array_intersect_key in array_iunique 5.0.3: is_subclass_of in define_once and valuesOf If you remove the respective optional parameters from debug_backtrace and mkdir and don't set Enum::$cacheReUsePackagePath, the package works fine on PHP 5.1.0 Workarounds to get the package running on PHP 5.0 should also be possible but are not recommended. Files ----- typesafeenum.lib.php - library loader, include this file to use the package Enum.php - Enum base class and generator cache/ - empty directory where the cached class files go. Must be writable! example/example.php - Example to demonstrate simple usage test/EnumTest.php - PHPUnit test case test/EnumBenchmark.php - Benchmark class test/run_benchmark.php - The script that I used for performance tests license.txt - BSD License readme.txt - the file you are reading right now Simple Usage: Generation ----- Typical usage of the generator: Enum::define('MyEnum', 'Value1', 'Value2', 'Value3', 'Value4'); doSomething(MyEnum::Value1()); function doSomething(MyEnum $myenum) { echo (string) $myEnum; switch ($myenum) { case MyEnum::Value1(): // do something for Value1 break; case MyEnum::Value2(): // do something for Value2 break; case MyEnum::Value3(): // do something for Value3 break; case MyEnum::Value4(): // do something for Value4 break; } } You can configure the behaviour of the generator with class variables of Enum, the most important one is $cacheEnabled. It is true by default but you may want to turn caching off, so that eval() will be used with the generated code instead of cached files. Enum::$cacheEnabled = false; Extended Usage: Methods ----- Besides define() there are two other public static methods in Enum: define_once(string $enumName, string $value1, string $value2, ... ) define_once works exactly like define but does nothing if the given Enumeration already is defined, similar to include_once and require_once. valuesOf(string $enumName) valuesOf returns all values (instances) of the given enumeration class. Extended Usage: Configuration ----- The caching can be configured with the following class variables: bool $checkCache: Check if cached files are outdated (you may want to disable this in productive environment). Defaults to true string $cacheDir: Where the generated files should be stored (path relative to this file). Defaults to 'cache' bool $cacheReUsePackagePath: If package path should be mapped to cache dir Useful if the same Enum names can occur in different packages. Defaults to false. Example: // in package1/subpackage/class.php: Enum::$cacheReUsePackagePath = true; Enum::define('MyEnum', 'FOO', 'BAR'); // in package2/otherclass.php: Enum::$cacheReUsePackagePath = true; Enum::define('MyEnum', 'MOO', 'NARF'); Now there will be two separate cached files: - cache/package1/subpackage/MyEnum.php - cache/package2/MyEnum.php Of course both packages cannot be used simultaneous since we don't have namespaces here. string $cachePackageRoot: Package root (necessary for $cacheReUsePackagePath). Defines from where the path should be reused. Extended Usage: Manual Definition ----- There are several scenarios where generating Enum classes with Enum::define() is not sufficient: - If you are using many Enum classes and need maximum performance (see next section) - If your system does not allow creation of files or eval() - If you want to use the Enum classes in a more flexible way (i.e. implementing a Comparable interface) In these cases you can easily define them yourself like that: final class MyEnum extends Enum { public static final function VALUE1() { return self::___get('MyEnum', 'VALUE1'); } public static final function VALUE2() { return self::___get('MyEnum', 'VALUE2'); } public static final function VALUE3() { return self::___get('MyEnum', 'VALUE3'); } } The parameters of ___get may be omitted, then the calling class and method will be determined automatically. If you add own functionality you can get the value of the current instance with (string)$this or parent::__tostring() Performance ----- Usually you should not worry about performance issues with the generator except you define really many Enums in a time-critical environment. Then you may consider resorting to manual definition. To decide if caching is the right choice you can test the speed on your system by running test/run_benchmark.php - you may want to change the first lines beforehand to determine the number of defined Enum classes. Note that depending on the filesystem caching does not necessary give an advantage, so the decision may be based on other factors.
  Files folder image Files  
File Role Description
Files folder imageexample (1 file)
Files folder imagetest (3 files)
Files folder imagecache (1 file)
Accessible without login Plain text file readme.txt Doc. Full documentation
Plain text file license.txt Lic. BSD License
Plain text file typesafeenum.lib.php Aux. Include this file to use the package
Plain text file Enum.php Class Enum base class and generator

  Files folder image Files  /  example  
File Role Description
  Accessible without login Plain text file example.php Example Simple example usage

  Files folder image Files  /  test  
File Role Description
  Plain text file EnumBenchmark.php Class Benchmark class
  Plain text file EnumTest.php Test PHPUnit test class
  Plain text file run_benchmark.php Aux. The script that I used for benchmarking

  Files folder image Files  /  cache  
File Role Description
  Plain text file EMPTY Data make this directory writable for PHP

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User Comments (1)
Now if only we had type safe callbacks :)
12 years ago (Tim Post)
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