php原型模式的研究

<?php

class Sea{}
class EarthSea extends Sea{}
class MarsSea extends Sea{}

class Plains{}
class EarthPlains{}
class MarsPlains{}

class Forest{}
class EarthForest{}
class MarsForest{}

class TerrainFactory{
private $sea;
private $forest;
private $plains;

function __construct(Sea $sea,Plains $plains,Forest $forest){
$this->sea = $sea;
$this->plains = $plains;
$this->forest = $forest;
}

function getSea(){
return clone $this->sea;
}
function getPlains(){
return clone $this->plains;
}
function getForest(){
return clone $this->forest;
}
}

$factory = new TerrainFactory(new EarthSea,new EarthPlains, new EarthForest);
print_r($factory->getSea());
print_r($factory->getPlains());
print_r($factory->getForest());

$mars_factory = new TerrainFactory(new MarsSea,new MarsPlains, new MarsForest);
print_r($mars_factory->getSea());
print_r($mars_factory->getPlains());
print_r($mars_factory->getForest());