狀態模式(State Pattern)

<?php
class Context
{
	private $likeState;
	private $fuckState;
	private $nullState;
	private $currentState;

	public function __construct()
	{
		$this->likeState    = new LikeState($this);
		$this->fuckState    = new FuckState($this);
		$this->nullState    = new NullState($this);
		$this->currentState = $this->nullState;
	}

	// 觸發器
	public function turnLike()
	{
		$this->currentState->like();
	}

	// 觸發器
	public function turnFuck()
	{
		$this->currentState->fuck();
	}

	// 設定目前狀態
	public function setState(IState $state)
	{
		$this->currentState = $state;
	}

	// 取得狀態-讚
	public function getLikeState()
	{
		return $this->likeState;
	}

	// 取得狀態-幹
	public function getFuckState()
	{
		return $this->fuckState;
	}

	// 取得狀態-無
	public function getNullState()
	{
		return $this->nullState;
	}
}

<?php
interface IState
{
	public function like();
	public function fuck();
}

<?php
class LikeState implements IState
{
	private $context;

	public function __construct(Context $contextNew)
	{
		$this->context = $contextNew;
	}

	public function like()
	{
		echo "讚 -> 無\n";
		$this->context->setState($this->context->getNullState());
	}

	public function fuck()
	{
		echo "讚 -> 幹\n";
		$this->context->setState($this->context->getFuckState());
	}
}

<?php
class FuckState implements IState
{
	private $context;

	public function __construct(Context $contextNew)
	{
		$this->context = $contextNew;
	}

	public function like()
	{
		echo "幹 -> 讚\n";
		$this->context->setState($this->context->getLikeState());
	}

	public function fuck()
	{
		echo "幹 -> 無\n";
		$this->context->setState($this->context->getNullState());
	}
}

<?php
class NullState implements IState
{
	private $context;

	public function __construct(Context $contextNew)
	{
		$this->context = $contextNew;
	}

	public function like()
	{
		echo "無 -> 讚\n";
		$this->context->setState($this->context->getLikeState());
	}

	public function fuck()
	{
		echo "無 -> 幹\n";
		$this->context->setState($this->context->getFuckState());
	}
}