设计模式 - 创造 - 对象池模式

对象池模式

• 对象池的客户端会向对象池中请求一个对象，然后使用这个返回的对象执行相关操作。当客户端使用完毕，它将把这个特定类型的工厂对象返回给对象池，而不是销毁掉这个对象。

    // StringReverseWorker.php
    namespace Creational\WorkerPool;
  
    class StringReverseWorker
    {
        public function run():string
        {
            return 'String'; 
        }
    }
  
    // WorkerPool.php
    namespace  Creational\WorkerPool;
  
    use  Countable;
  
    class  WorkerPool  implements  Countable
    {
        private  array  $occupiedWorkers = [];
        private  array  $freeWorks = [];
        public  function  count(): int
        {
            return  count($this->occupiedWorkers) + count($this->freeWorks);
        }
  
         public  function  get()
        {
             if(count($this->freeWorks) == 0){
                $worker = new  StringReverseWorker();
            }else{
                 $worker = array_pop($this->freeWorks);
  
            }
             $this->occupiedWorkers[spl_object_hash($worker)] = $worker;
            return  $worker;
        }
  
         public  function  dispose(StringReverseWorker  $worker)
        {
             $key = spl_object_hash($worker);
             if(isset($this->occupiedWorkers[$key])){
                 unset($this->occupiedWorkers[$key]);
                 $this->freeWorks[$key] = $worker;
            }
        }
    }

    // WorkerPoolTest.php
    namespace Tests;
  
    use Creational\WorkerPool\WorkerPool;
    use PHPUnit\Framework\TestCase;
  
    class WorkerPoolTest extends TestCase
    {
        public function testWp()
        {
            $pool = new WorkerPool();
            $p1 = $pool->get();
            $p2 = $pool->get();
            //$this->assertEquals($p1, $p2);
            //$this->assertObjectEquals($p1, $p2);
  
            $this->assertCount(2, $pool);
            $this->assertNotSame($p1, $p2);
        }
  
        public function testCanGetSameInstanceTwiceWhenDisposingItFirst()
        {
            $pool = new WorkerPool();
            $worker1 = $pool->get();
            $pool->dispose($worker1);
            $worker2 = $pool->get();
  
            $this->assertCount(1, $pool);
            $this->assertSame($worker1, $worker2);
        }
    }

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