purpose
In the example of the delegation pattern, an object delegates the tasks it wants to perform to the helper object associated with it. In the example, the "group leader" declares the writeCode method and uses it. In fact, the "group leader" delegates writeCode to the writeBadCode method of the "rookie developer". This reversal of responsibility hides the details of its internal implementation of writeBadCode.
example
Please read the code in JuniorDeveloper.php, TeamLead.php, and then combine them in Usage.php.
Code
- TeamLead.php
<?php
namespace DesignPatterns\More\Delegation;
class TeamLead
{
/**
* @var JuniorDeveloper
*/
private $junior;
/**
* @param JuniorDeveloper $junior
*/
public function __construct(JuniorDeveloper $junior)
{
$this->junior = $junior;
}
public function writeCode(): string
{
return $this->junior->writeBadCode();
}
}
- JuniorDeveloper.php
<?php
namespace DesignPatterns\More\Delegation;
class JuniorDeveloper
{
public function writeBadCode(): string
{
return 'Some junior developer generated code...';
}
}
test
- Tests/DelegationTest.php
<?php
namespace DesignPatterns\More\Delegation\Tests;
use DesignPatterns\More\Delegation;
use PHPUnit\Framework\TestCase;
class DelegationTest extends TestCase
{
public function testHowTeamLeadWriteCode()
{
$junior = new Delegation\JuniorDeveloper();
$teamLead = new Delegation\TeamLead($junior);
$this->assertEquals($junior->writeBadCode(), $teamLead->writeCode());
}
}
The Growth Path of PHP Internet Architect * The Ultimate Guide to "Design Patterns"
PHP Internet Architect 50K Growth Guide + Industry Problem Solving Guide (Continuous Update)
Interview with 10 companies, get 9 offers, PHP interview questions in 2020
★If you like my article and want to communicate and learn with more senior developers, get more technical consultation and guidance related to interviews with big companies, welcome to join our group, password: phpzh
The latest PHP advanced tutorial in 2020, full series!
If the content is good, I hope everyone will support and encourage you to give a like/like, and welcome to communicate together; in addition, if you have any questions, you can suggest what you want to see in the comments.