设计模式——访问者模式

说明

示例

下面看下访问者模式的代码实现

interface Visitor{
    public function visit(Subject $sub);
}

class MyVisitor implements Visitor{
    public function visit(Subject $sub){
        echo "visit the subject：" . $sub->getSubject();
    }
}

interface Subject{
    public function accept(Visitor $visitor);
    public function getSubject(): string;
}

class MySubject implements Subject{
    public function accept(Visitor $visitor){
        $visitor->visit($this);
    }
    public function getSubject(): string{
        return "love";
    }
}


// 调用
$visitor = new MyVisitor();
$sub = new MySubject();
$sub->accept($visitor);
// output:  visit the subject：love

总结