组合模式

<?php
abstract class Component{
    function __construct($strName){
        $this->m_strName = $strName;
    }
    abstract function Add($com);
    protected function Remove($com){}
    abstract function Display($nDepth);

}

class Leaf extends Component{
    function Add($com){
        print_r("Leaf can‘t add!");
    }
    function Display($nDepth){
        $strtemp = "";
        for($i=0;$i<$nDepth;$i++){
            $strtemp.="-";
        }
        $strtemp=$strtemp.($this->m_strName)."\n";
        print_r($strtemp);
    }
}

class Composite extends Component{
    protected $m_strName="";
    protected $c=array();
    function __construct($strName){
        $this->m_strName = $strName;
    }
    function Add($com){
        $this->c[] = $com;
    }
    function Remove($com){
        $key = array_search($com, $this->c);
        if($key != false)unset($this->c[$key]);
    }
    function Display($nDepth){
        $strtemp = "";
        for($i=0;$i<$nDepth;$i++){
            $strtemp.="-";
        }
        $strtemp=$strtemp.($this->m_strName)."\n";
        print_r($strtemp);
        foreach($this->c as $v){
            $v->Display($nDepth+2);
        }
    }
}

$p = new Composite("第一级目录");
$p->Add(new Leaf("第二级目录1"));
$s1 = new Leaf("第二级目录2");
$p->Add($s1);
$s2 = new Composite("第二级目录3");
$s2->Add(new Leaf("第三级目录1"));
$t1 = new Composite("第三级目录2");
$t1->Add(new Leaf("第四级目录"));
$s2->Add($t1);
$p->Add($s2);
$p->Remove($s1);
$p->Display(1);