What is the reflection mechanism of PHP?

What is reflection?

It refers to the PHP running state, extending the parsing PHP program, exporting or extracting details about classes, methods, properties, parameters, etc., including comments. This dynamic acquisition of information and the ability to dynamically invoke an object's methods is called the Reflection API. Reflection is an API that manipulates the meta-model of an object-oriented paradigm and is powerful in helping us to build complex, scalable applications.

The purpose is to automatically load plugins, automatically generate documents, and even to augment the PHP language.

The PHP reflection API consists of several classes that help us to access the program's metadata or to interact with the related annotations. With reflection we can obtain methods such as class implementations, create an instance of a class (unlike the one created with new), Invoke a method (also different from a regular call), pass a parameter, and invoke the static method of the class dynamically.

The Reflection API is a PHP built-in OOP technology extension that includes classes, exceptions, and interfaces that are used in combination to help us analyze other classes, interfaces, methods, properties, methods, and extensions. These OOP extensions are known as reflections.

With Reflectionclass, we can get the following information for the person class:

1) Constant contants
2) Property Names
3) method names static
4) Property Static Properties
5) Namespace Namespace
6) Whether the person class is final or abstract

Example

Class Person {  /**   * For the sake of demonstration, we ' re setting this private   */  private $_allowdynamicat Tributes = false;  /** type=primary_autoincrement */  protected $id = 0;  /** Type=varchar length=255 NULL */  protected $name;  /** type=text NULL */  protected $biography;    Public Function getId ()    {      return $this->id;    }    Public Function SetId ($v)    {      $this->id = $v;    }    Public Function GetName ()    {      return $this->name;    }    Public Function SetName ($v)    {      $this->name = $v;    }    Public Function getbiography ()    {      return $this->biography;    }    Public Function setbiography ($v)    {      $this->biography = $v;    }}

Next reflect it, as long as the class name "person" is passed to Reflectionclass, you can:

$class = new Reflectionclass (' person ');//The Reflection class $instance = $class->newinstanceargs ($args);// The equivalent of instantiating the person class

1) Get Attributes (properties):

$properties = $class->getproperties (); foreach ($properties as $property) {  echo $property->getname (). " \ n ";} Output://_allowdynamicattributes//id//name//biography

By default, Reflectionclass will get all of the properties, private and protected can also. If you want to get only the private property, you need to pass an additional parameter:

$private _properties = $class->getproperties (reflectionproperty::is_private);

List of available parameters:

Reflectionproperty::is_static
Reflectionproperty::is_public
reflectionproperty::is_protected
Reflectionproperty::is_private

If you want to get both the public and private properties, write this: Reflectionproperty::is_public | Reflectionproperty::is_protected.

The $property->getName() property name can be obtained by the.

2) Get Comments:

A note to the property can be obtained by getdoccomment.

foreach ($properties as $property) {  if ($property->isprotected ()) {    $docblock = $property Getdoccomment ();    Preg_match ('/type\= ([a-z_]*)/', $property->getdoccomment (), $matches);    echo $matches [1]. " \ n ";  }} output://primary_autoincrement//varchar//Text

3) methods to get classes

Get Method (Methods): getMethods() gets all the methods to the class by.

4) Method of executing the class:

$instance->getbiography (); Execute the method in person getbiography//or: $ec = $class->getmethod (' getName '); Gets the GetName method in the Person class $ec->invoke ($instance);    Execute the GetName method