<?php
 
interface Visitor {
 public function visitConcreteElementA(ConcreteElementA $elementA);
 public function visitConcreteElementB(concreteElementB $elementB);
}
 
interface Element {
 public function accept(Visitor $visitor);
}
 
/**
 * 具体的访问者1
 */
class ConcreteVisitor1 implements Visitor {
 public function visitConcreteElementA(ConcreteElementA $elementA) {
 echo $elementA->getName() . " visitd by ConcerteVisitor1 <br />";
 }
 
 public function visitConcreteElementB(ConcreteElementB $elementB) {
 echo $elementB->getName() . " visited by ConcerteVisitor1 <br />";
 }
 
}
 
/**
 * 具体的访问者2
 */
class ConcreteVisitor2 implements Visitor {
 public function visitConcreteElementA(ConcreteElementA $elementA) {
 echo $elementA->getName() . " visitd by ConcerteVisitor2 <br />";
 }
 
 public function visitConcreteElementB(ConcreteElementB $elementB) {
 echo $elementB->getName() . " visited by ConcerteVisitor2 <br />";
 }
 
}
 
/**
 * 具体元素A
 */
class ConcreteElementA implements Element {
 private $_name;
 
 public function __construct($name) {
 $this->_name = $name;
 }
 
 public function getName() {
 return $this->_name;
 }
 
 /**
 * 接受访问者调用它针对该元素的新方法
 * @param Visitor $visitor
 */
 public function accept(Visitor $visitor) {
 $visitor->visitConcreteElementA($this);
 }
 
}
 
/**
 * 具体元素B
 */
class ConcreteElementB implements Element {
 private $_name;
 
 public function __construct($name) {
 $this->_name = $name;
 }
 
 public function getName() {
 return $this->_name;
 }
 
 /**
 * 接受访问者调用它针对该元素的新方法
 * @param Visitor $visitor
 */
 public function accept(Visitor $visitor) {
 $visitor->visitConcreteElementB($this);
 }
 
}
 
/**
 * 对象结构 即元素的集合
 */
class ObjectStructure {
 private $_collection;
 
 public function __construct() {
 $this->_collection = array();
 }
 
 
 public function attach(Element $element) {
 return array_push($this->_collection, $element);
 }
 
 public function detach(Element $element) {
 $index = array_search($element, $this->_collection);
 if ($index !== FALSE) {
 unset($this->_collection[$index]);
 }
 
 return $index;
 }
 
 public function accept(Visitor $visitor) {
 foreach ($this->_collection as $element) {
 $element->accept($visitor);
 }
 }
}
 
class Client {
 
 /**
 * Main program.
 */
 public static function main() {
 $elementA = new ConcreteElementA("ElementA");
 $elementB = new ConcreteElementB("ElementB");
 $elementA2 = new ConcreteElementB("ElementA2");
 $visitor1 = new ConcreteVisitor1();
 $visitor2 = new ConcreteVisitor2();
 
 $os = new ObjectStructure();
 $os->attach($elementA);
 $os->attach($elementB);
 $os->attach($elementA2);
 $os->detach($elementA);
 $os->accept($visitor1);
 $os->accept($visitor2);
 }
 
}
 
Client::main();
?>