Injector
========
A dependency injection class based on Pimple 2
**Author**: Emmanuel Antico<br/>
**Last Modification**: 2014/07/02<br/>
**Version**: 3.1.0
<br/>
Installation
------------
<br/>
Installation is made via composer. Add the following lines to the composer.json file in your project.
<br/>
**Composer**
```json
{
"require": {
"injector/injector": "~3.0"
}
}
```
<br/>
Dependecies
------------
<br/>
Injector requires the following packages to be installed:
* [Pimple 2.1](https://github.com/fabpot/Pimple "")
* [Minime\Annotations 1.13](https://github.com/marcioAlmada/annotations "")
<br/>
How to use
------------
<br/>
Injector is a dependency injection library that uses the *Pimple\Container* class to initialize a set of properties within an instance. This is done by adding the appropiate annotations to the class declaration.
<br/>
>Step 1: Create a Provider
A provider is a class that implements the *Pimple\ServiceProviderInterface* interface. This class sets a number of services (and parameters) inside a container.
```php
<?php
namespace Acme\Providers;
use Pimple\Container;
use Pimple\ServiceProviderInterface;
use Acme\Services\Logger;
use Acme\Services\MySQLConnection;
class MainProvider implements ServiceProviderInterface {
public function register(Container $container) {
//add some services
$container['logger'] = function ($c) {
return new Logger();
};
$container['conn'] = function ($c) {
return new MySQLConnection('usr', 'psw');
};
$container['environment'] = 'development';
}
}
```
<br/>
>Step 2: Configure your class
In order to indicate a class provider we add the @inject.provider annotation followed by the provider class name. Dependencies can now be injected through the @inject.service and @inject.param annotations.
```php
<?php
namespace Acme\Components;
/**
* @inject.provider Acme\Providers\MainProvider
*/
class MyComponent {
private $name;
private $env;
/**
* @inject.service logger
*/
private $logger;
/**
* @inject.service conn
*/
private $connection;
/**
* @inject.param $env environment
*/
public function __construct($name, $env) {
$this->name = $name;
$this->env = $env;
}
public function getEnvironment() {
return $this->env;
}
public function getName() {
return $this->name;
}
public function getLogger() {
return $this->logger;
}
public function getConnection() {
return $this->connection;
}
}
```
<br/>
>Step 3: Create an instance
Instances are created through the *create* static method in the *Injector\Injector* class. Additional arguments could be added as an array.
```php
<?php
use Injector\Injector;
use Acme\Services\SQLiteConnection;
$component = Injector::create('Acme\Components\MyComponent', ['My Component']);
$component->getEnvironment(); //returns 'development'
$component->getName(); //returns 'My Component'
$component->getLogger()->debug('Component initialized');
//overriding a constructor parameter
$component = Injector::create('Acme\Components\MyComponent', ['My Component', 'production']);
$component->getEnvironment(); //returns 'production'
//filtering dependencies
$component = Injector::create('Acme\Components\MyComponent', ['My Component'], ['logger']);
$component->getLogger(); //Logger
$component->getConnection(); // NULL
//overriding dependencies
$component = Injector::create('Acme\Components\MyComponent', ['My Component'], null, ['conn' => new SQLiteConnection('file.db')]);
$component->getConnection(); // SQLiteConnection
```
<br/>
>Step 3 (alt): Inject dependencies
You could also inject dependencies directly through the *inject* method using a custom made container.
```php
<?php
use Injector\Injector;
//create container
$container = new Pimple\Container;
$provider = new Acme\Providers\MainProvider();
$provider->register($container);
//inject dependencies
$component = new CustomComponent();
Injector::inject($component, $container);
//...
$component->getLogger()->debug('Component initialized');
```
<br/>
License
-------
<br/>
This code is licensed under the BSD 2-Clause license.
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