PHPCombined modeThe first implementation method
'; } interface Component { public function doAction(); } /** * 局部类 */ class Leaf implements Component { public function doAction() { echoLine('The [leaf] doAction!'); } } /** * 组合模式的一个问题是如何实现 add 和 remove 方法。一般的组合模式会在抽象超类中添加 add * 和 remove 方法。这可以确保模式中的所有类都共享同一个借口,但这同时也意味着局部类也必须 * 实现这些方法。实际上,我们并不希望在局部类中实现这些方法。 * * 需要担心的问题: * 1. 组合操作的成本。 * 2. 对象持久化问题。难以直接将数据保存在关系型数据中,但其数据却非常适合持久化为 XML。 */ class Composite implements Component { /** * component container */ private $container = array(); public function doAction() { echoLine('The [Composite] doAction!'); foreach ($this->container as $c) $c->doAction(); } /** * add component * @param Component $c */ public function addComponent(Component $c) { if(!in_array($c, $this->container, true)) $this->container[] = $c; } /** * remove conponent * @param Component $c */ public function removeComponent(Component $c) { $this->container = array_diff($this->container, array($c)); } /** * get all components * @return array */ public function getComponents() { return $this->container; } } // test code $leaf = new Leaf(); $composite = new Composite(); $composite->addComponent($leaf); $composite->addComponent(new Leaf()); $composite->addComponent(new Leaf()); $composite->doAction();
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