php享元模式(flyweight pattern)

周日一大早，今天要送老婆孩子去火车站，

所以练代码要早点哈。

<?php
/*
The flyweight pattern is about performance and resource reduction, sharing as much
data as possible between similar objects. What this means is that instances of a class
which are identical are shared in an implementation. This works best when a large
number of same class instances are expected to be created.
*/

interface Shape{
    public function draw();
}

class Circle implements Shape {
    private $color;
    private $radius;

    public function __construct($color) {
        $this->color = $color;
    }

    public function draw() {
        echo sprintf('Color %s, radius %s <br/>', $this->color,
            $this->radius);
    }

    public function setRadius($radius) {
        $this->radius = $radius;
    }
}

class ShapeFactory {
    private $circleMap;

    public function getCircle($color) {
        if (!isset($this->cicrleMap[$color])) {
            $circle = new Circle($color);
            $this->circleMap[$color] = $circle;
        }
        return $this->circleMap[$color];
    }
}

$shapeFactory = new ShapeFactory();
$circle = $shapeFactory->getCircle('yellow');
$circle->setRadius(10);
$circle->draw();

$shapeFactory = new ShapeFactory();
$circle = $shapeFactory->getCircle('orange');
$circle->setRadius(15);
$circle->draw();

$shapeFactory = new ShapeFactory();
$circle = $shapeFactory->getCircle('yellow');
$circle->setRadius(20);
$circle->draw();
?>