随机应变的访问者模式（Visitor Pattern）-php教程-PHP中文网

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随机应变的访问者模式（Visitor Pattern）

Nov 12, 2016 pm 01:39 PM

有一天，技术总监说要知道所有技术员工的工作情况，第二天，老板说要知道所有员工的业绩，再有一天，HR总监要知道所有员工的工资。每一次都是利用组合模式遍历出员工后获取员工的相关信息。也许你会说，直接把所有的信息全输出就行了，那估计你要被老板叼了，老板就想知道业绩，你把一个大表给看找，好吧，你可以回家了！让访问者模式来帮我们解决这个问题，类图如下：

可以看出，有个visitor，这就是访问者，貌似有点像代理的感觉。在讲代理模式就已经提到访问者模式本选购是在更特殊的场合采用了代理模式。实现代码：

&lt;?php
interface IVisitor{
public function visitCommonEmployee( CommonEmployee $commonEmployee );
public function visitManager( Manager $manager );
}
class Visitor implements IVisitor{
public function visitCommonEmployee( CommonEmployee $commonEmployee ) {
echo $this-&gt;getCommonEmployee( $commonEmployee );
}
public function visitManager( Manager $manager ) {
echo $this-&gt;getManagerInfo( $manager );
}
private function getBasicInfo( Employee $employee ) {
$info = &quot;姓名：&quot;.$employee-&gt;getName().&quot;\t&quot;;
return $info;
}
private function getCommonEmployee( CommonEmployee $commonEmployee ) {
$basicInfo = $this-&gt;getBasicInfo( $commonEmployee );
$otherInfo = &quot;工作：&quot;.$commonEmployee-&gt;getJob().&quot;\n&quot;;
return $basicInfo.$otherInfo;
}
private function getManagerInfo( Manager $manager ) {
$basicInfo = $this-&gt;getBasicInfo( $manager );
$otherInfo = &quot;业绩：&quot;.$manager-&gt;getPerformance().&quot;\n&quot;;
return $basicInfo.$otherInfo;
}
}
abstract class Employee {
private $name;
public function getName() {
return $this-&gt;name;
}
public function setName( $name ) {
$this-&gt;name = $name;
}
public function accept( IVisitor $visitor ) {
$method = &#39;visit&#39;.get_class( $this );
$visitor-&gt;$method( $this );
}
}
class CommonEmployee extends Employee{
private $job;
public function getJob() {
return $this-&gt;job;
}
public function setJob( $job ) {
$this-&gt;job = $job;
}
}
class Manager extends Employee{
private $performance;
public function getPerformance() {
return $this-&gt;performance;
}
public function setPerformance( $performance ) {
$this-&gt;performance = $performance;
}
}
$empList = array();
$zhangsan = new CommonEmployee();
$zhangsan-&gt;setName( &#39;张三&#39; );
$zhangsan-&gt;setJob( &#39;coding&#39; );
$empList[] = $zhangsan;
$lisi = new CommonEmployee();
$lisi-&gt;setName( &#39;李四&#39; );
$lisi-&gt;setJob( &#39;coding&#39; );
$empList[] = $lisi;
$wangwu = new Manager();
$wangwu-&gt;setName( &#39;马云&#39; );
$wangwu-&gt;setPerformance( &#39;负值，但拍马屁厉害&#39; );
$empList[] = $wangwu;
foreach ($empList as $value) {
$value-&gt;accept(new Visitor());
}
?&gt;