PHP简单工厂与抽象工厂对比

PHP简单工厂与抽象工厂对比

工厂模式有不同的变体。简单工厂、工厂方法、抽象工厂各有适用场景。今天说说各种工厂模式的区别和实现。

简单工厂。

```php
interface Logger
{
public function log(string $message): void;
}

class FileLogger implements Logger
{
public function log(string $message): void
{
file_put_contents('/tmp/app.log', $message . "\n", FILE_APPEND);
}
}

class EchoLogger implements Logger
{
public function log(string $message): void
{
echo "[LOG] $message\n";
}
}

class NullLogger implements Logger
{
public function log(string $message): void {}
}

// 简单工厂
class LoggerFactory
{
public static function create(string $type): Logger
{
return match ($type) {
'file' => new FileLogger(),
'echo' => new EchoLogger(),
'null' => new NullLogger(),
default => throw new InvalidArgumentException("不支持的日志类型: $type"),
};
}
}

$logger = LoggerFactory::create('echo');
$logger->log('测试');
?>

工厂方法。

```php
abstract class LoggerCreator
{
abstract public function createLogger(): Logger;

public function log(string $message): void
{
$logger = $this->createLogger();
$logger->log($message);
}
}

class FileLoggerCreator extends LoggerCreator
{
public function createLogger(): Logger
{
return new FileLogger();
}
}

class EchoLoggerCreator extends LoggerCreator
{
public function createLogger(): Logger
{
return new EchoLogger();
}
}
?>

抽象工厂。

```php
interface Button
{
public function render(): string;
}

interface Checkbox
{
public function render(): string;
}

class WindowsButton implements Button
{
public function render(): string { return "确定"; }
}

class MacButton implements Button
{
public function render(): string { return "确定"; }
}

class WindowsCheckbox implements Checkbox
{
public function render(): string { return ""; }
}

class MacCheckbox implements Checkbox
{
public function render(): string { return ""; }
}

interface UIFactory
{
public function createButton(): Button;
public function createCheckbox(): Checkbox;
}

class WindowsFactory implements UIFactory
{
public function createButton(): Button { return new WindowsButton(); }
public function createCheckbox(): Checkbox { return new WindowsCheckbox(); }
}

class MacFactory implements UIFactory
{
public function createButton(): Button { return new MacButton(); }
public function createCheckbox(): Checkbox { return new MacCheckbox(); }
}

function createUI(UIFactory $factory): void
{
echo $factory->createButton()->render() . "\n";
echo $factory->createCheckbox()->render() . "\n";
}

createUI(new WindowsFactory());
createUI(new MacFactory());
?>

工厂模式的选择依据。

// 简单工厂：创建逻辑简单，只有一个工厂类
// 工厂方法：每个产品对应一个工厂子类
// 抽象工厂：创建一系列相关产品

简单工厂适合产品种类少的场景。工厂方法让新增产品不需要修改工厂类。抽象工厂用于创建产品族。选择哪种模式取决于具体需求。