2.1. Adapter (Adapter / Wrapper)¶
2.1.1. Przeznaczenie¶
Adapter pozwala z jednej strony na opakowanie interfejsu istniejącej klasy nowym, kompatybilnym z naszą aplikacją. Z drugiej strony pozwala współpracować klasom o niekompatybilnych interfejsach poprzez udostępnienie nowego interfejsu (bazującego na niekompatybilnych interfejsach).
2.1.2. Przykłady¶
- Adaptery bibliotek do łączenia się z bazami danych.
- Używanie różnych webserwisów i adapterów pozwala nam w spójny sposób korzystać z danych (na przykład kiedy korzystamy z ogólnodostępnych API).
2.1.3. Diagram UML¶

2.1.4. Kod¶
Ten kod znajdziesz również na GitHub.
Book.php
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | <?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
interface Book
{
public function turnPage();
public function open();
public function getPage(): int;
}
|
PaperBook.php
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 | <?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
class PaperBook implements Book
{
private int $page;
public function open(): void
{
$this->page = 1;
}
public function turnPage(): void
{
$this->page++;
}
public function getPage(): int
{
return $this->page;
}
}
|
EBook.php
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | <?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
interface EBook
{
public function unlock();
public function pressNext();
/**
* returns current page and total number of pages, like [10, 100] is page 10 of 100
*
* @return int[]
*/
public function getPage(): array;
}
|
EBookAdapter.php
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 | <?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
/**
* This is the adapter here. Notice it implements Book,
* therefore you don't have to change the code of the client which is using a Book
*/
class EBookAdapter implements Book
{
public function __construct(protected EBook $eBook)
{
}
/**
* This class makes the proper translation from one interface to another.
*/
public function open()
{
$this->eBook->unlock();
}
public function turnPage()
{
$this->eBook->pressNext();
}
/**
* notice the adapted behavior here: EBook::getPage() will return two integers, but Book
* supports only a current page getter, so we adapt the behavior here
*/
public function getPage(): int
{
return $this->eBook->getPage()[0];
}
}
|
Kindle.php
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 | <?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
/**
* this is the adapted class. In production code, this could be a class from another package, some vendor code.
* Notice that it uses another naming scheme and the implementation does something similar but in another way
*/
class Kindle implements EBook
{
private int $page = 1;
private int $totalPages = 100;
public function pressNext()
{
$this->page++;
}
public function unlock()
{
}
/**
* returns current page and total number of pages, like [10, 100] is page 10 of 100
*
* @return int[]
*/
public function getPage(): array
{
return [$this->page, $this->totalPages];
}
}
|
2.1.5. Testy¶
Tests/AdapterTest.php
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 | <?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter\Tests;
use DesignPatterns\Structural\Adapter\PaperBook;
use DesignPatterns\Structural\Adapter\EBookAdapter;
use DesignPatterns\Structural\Adapter\Kindle;
use PHPUnit\Framework\TestCase;
class AdapterTest extends TestCase
{
public function testCanTurnPageOnBook()
{
$book = new PaperBook();
$book->open();
$book->turnPage();
$this->assertSame(2, $book->getPage());
}
public function testCanTurnPageOnKindleLikeInANormalBook()
{
$kindle = new Kindle();
$book = new EBookAdapter($kindle);
$book->open();
$book->turnPage();
$this->assertSame(2, $book->getPage());
}
}
|