目的
在初始化实例成本高，实例化率高，可用实例不足的情况下，对象池可以极大地提升性能。在创建对象（尤其是通过网络）时间花销不确定的情况下，通过对象池在可期时间内就可以获得所需的对象。
无论如何，对象池模式在需要耗时创建对象方面，例如创建数据库连接，套接字连接，线程和大型图形对象（比方字体或位图等），使用起来都是大有裨益的。在某些情况下，简单的对象池（无外部资源，只占内存）可能效率不高，甚至会有损性能。
UML 类图
代码
WorkerPool.php
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<?phpnamespace DesignPatterns\Creational\Pool;class WorkerPool implements \Countable{ /** * @var StringReverseWorker[] */ private $occupiedWorkers = []; /** * @var StringReverseWorker[] */ private $freeWorkers = []; public function get(): StringReverseWorker { if (count($this->freeWorkers) == 0) { $worker = new StringReverseWorker(); } else { $worker = array_pop($this->freeWorkers); } $this->occupiedWorkers[spl_object_hash($worker)] = $worker; return $worker; } public function dispose(StringReverseWorker $worker) { $key = spl_object_hash($worker); if (isset($this->occupiedWorkers[$key])) { unset($this->occupiedWorkers[$key]); $this->freeWorkers[$key] = $worker; } } public function count(): int { return count($this->occupiedWorkers) + count($this->freeWorkers); }} |
StringReverseWorker.php
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<?phpnamespace DesignPatterns\Creational\Pool;class StringReverseWorker{ /** * @var \DateTime */ private $createdAt; public function __construct() { $this->createdAt = new \DateTime(); } public function run(string $text) { return strrev($text); }} |
测试
Tests/PoolTest.php
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<?phpnamespace DesignPatterns\Creational\Pool\Tests;use DesignPatterns\Creational\Pool\WorkerPool;use PHPUnit\Framework\TestCase;class PoolTest extends TestCase{ public function testCanGetNewInstancesWithGet() { $pool = new WorkerPool(); $worker1 = $pool->get(); $worker2 = $pool->get(); $this->assertCount(2, $pool); $this->assertNotSame($worker1, $worker2); } public function testCanGetSameInstanceTwiceWhenDisposingItFirst() { $pool = new WorkerPool(); $worker1 = $pool->get(); $pool->dispose($worker1); $worker2 = $pool->get(); $this->assertCount(1, $pool); $this->assertSame($worker1, $worker2); }} |
以上就是浅谈PHP设计模式之对象池模式Pool的详细内容，更多关于PHP设计模式之对象池模式Pool的资料请关注服务器之家其它相关文章！
原文链接：https://www.cnblogs.com/phpyu/p/13589787.html
