拦截过滤器模式

//interceptingFilter
interface Filter
{
    public function execute($request);
}

class AuthenticationFilter implements Filter
{
    public function execute($request)
    {
        echo "Authenticating request: " . $request;
    }
}

class DebugFilter implements Filter
{
    public function execute($request)
    {
        echo "request log: " . $request;
    }
}

class Target
{
    public function execute($request)
    {
        echo "Executing request: " . $request;
    }
}

class FilterChain
{
    private $filters = [];
    private $target = null;
    
    public function __construct()
    {
        
    }
    
    public function addFilter($filter)
    {
        $this->filters[] = $filter;
    }
    
    public function execute($request)
    {
        foreach ($this->filters as $filter) {
            $filter->execute($request);
        }
        $this->target->execute($request);
    }
    
    public function setTarget($target)
    {
        $this->target = $target;
    }
}

class FilterManager
{
    public $filterChain = null;
    
    public function __construct($filter)
    {
        $this->filterChain = new FilterChain();
        $this->filterChain->setTarget($filter);
    }
    
    public function setFilter($filter)
    {
        $this->filterChain->addFilter($filter);
    }
    
    public function filterRequest($request)
    {
        $this->filterChain->execute($request);
    }
}

class Client
{
    public $filterManager = null;
    
    public function setFilterManager($filterManager)
    {
        $this->filterManager = $filterManager;
    }
    
    public function sendRequest($request)
    {
        $this->filterManager->filterRequest($request);
    }
}

$FilterManager = new FilterManager(new Target());
$FilterManager->setFilter(new AuthenticationFilter());
$FilterManager->setFilter(new DebugFilter());

$Client = new Client();
$Client->setFilterManager($FilterManager);
$Client->sendRequest("HOME");

参考文章 http://www.runoob.com/design-pattern/intercepting-filter-pattern.html